Multiple Hamartoma Syndrome
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 29 August, 2019 using data from PubMed, MeSH and CancerIndex
Mutated Genes and Abnormal Protein Expression (8)
Clicking on the Gene or Topic will take you to a separate more detailed page. Sort this list by clicking on a column heading e.g. 'Gene' or 'Topic'.
|PTEN ||10q23.31 ||BZS, DEC, CWS1, GLM2, MHAM, TEP1, MMAC1, PTEN1, 10q23del ||Germline ||-PTEN mutations in Cowdon Syndrome || 307|
|AKT1 ||14q32.33 ||AKT, PKB, RAC, CWS6, PRKBA, PKB-ALPHA, RAC-ALPHA ||Germline ||-Occasional AKT1 mutations in Cowden Syndrome || 23|
|BMPR1A ||10q23.2 ||ALK3, SKR5, CD292, ACVRLK3, 10q23del || ||-BMPR1A and Cowdon Syndrome || 10|
|KLLN ||10q23.31 ||CWS4, KILLIN ||Germline |
|-Germline KLLN methylation in Cowden Syndrome and increased risk of cancer || 9|
|SDHB ||1p36.13 ||IP, SDH, CWS2, PGL4, SDH1, SDH2, SDHIP ||Germline ||-SDHB mutations in Cowdon Syndrome || 9|
|PIK3CA ||3q26.32 ||MCM, CWS5, MCAP, PI3K, CLOVE, MCMTC, PI3K-alpha, p110-alpha ||Germline ||-PIK3CA germline alterations in Cowdon S... || 8|
|SDHD ||11q23.1 ||PGL, CBT1, CWS3, PGL1, QPs3, SDH4, cybS, CII-4 || ||-SDHD mutations in Cowdon Syndrome || 7|
|RASAL1 ||12q24.13 ||RASAL ||Germline ||-Occasional RASAL1 germline alterations in Cowdon Syndrome. || 1|
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
Xu Y, Fu WZ, He JW, et al.[A clinical study of Proteus syndrome caused by a mosaic somatic mutation in AKT1 gene].
Zhonghua Nei Ke Za Zhi. 2019; 58(7):508-513 [PubMed
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The discoveries of new genes underlying genetic skin diseases have occurred at a rapid pace, supported by advances in DNA sequencing technologies. These discoveries have translated to an improved understanding of disease mechanisms at a molecular level and identified new therapeutic options based on molecular targets. This article highlights just a few of these recent discoveries for a diverse group of skin diseases, including tuberous sclerosis complex, ichthyoses, overgrowth syndromes, interferonopathies, and basal cell nevus syndrome, and how this has translated into novel targeted therapies and improved patient care.
BACKGROUND: Somatic overgrowth conditions, including Proteus syndrome, Sturge-Weber syndrome, and PIK3CA-related overgrowth spectrum, are caused by post-zygotic pathogenic variants, result in segmental mosaicism, and give rise to neural, cutaneous and/or lipomatous overgrowth. These variants occur in growth-promoting pathways leading to cellular proliferation and expansion of tissues that arise from the affected cellular lineage.
METHODS: We report on 80 serial patients evaluated for somatic overgrowth conditions in a diagnostic laboratory setting, including three prenatal patients. In total, 166 tissues from these 80 patients were subjected to targeted sequencing of an 8-gene panel capturing 10.2 kb of sequence containing known pathogenic variants associated with somatic overgrowth conditions. Deep next-generation sequencing was performed with the IonTorrent PGM platform at an average depth typically >5,000×.
RESULTS: Likely pathogenic or pathogenic variants were identified in 36 individuals and variants of unknown significance in four. The overall molecular diagnostic yield was 45% but was highly influenced by both submitted tissue type and phenotype. In the prenatal setting, two patients had pathogenic variants identified in cultured amniocytes but in a third patient, the pathogenic variant was only present in post-natal tissues. Finally, expanding the test to include full gene sequencing of PIK3CA in contrast to targeted sequencing identified likely pathogenic variants in 3 of 7 patients that tested negative on the original panel.
CONCLUSION: Next-generation sequencing has enabled sensitive detection of somatic pathogenic variants associated with overgrowth conditions. However, as the pathogenic variant allele frequency varies by tissue type within an individual, submission of affected tissue(s) greatly increases the chances of a molecular diagnosis.
BACKGROUND: Cowden's syndrome (OMIM:158350), a rare genetic disorder (incidence ~ 1:250,000), is caused by mutations of the tumor suppressor gene PTEN. In this report, we describe clinical manifestations of a 56-year-old patient diagnosed with Cowden's syndrome and his family with PTEN mutations. The family has an unusually high number of offspring with autism spectrum disorder.
CASE PRESENTATION: Except for his 80-year-old Caucasian father, all of our index case's living Caucasian kindred (three children, brother, and nephew) had PTEN mutations and macrocephaly. Prior to genetic testing, his mother and sister died of breast cancer at 42 and 38 years old, respectively. After PTEN mutation was identified, our patient underwent complete thyroidectomy (histology showing micropapillary carcinoma) and right nephrectomy for renal cell carcinoma. All of his three children (13-year-old son, 11- and 8-year-old daughters) have been diagnosed with autism spectrum disorder. His son and brother underwent total thyroidectomy. His nephew had thyroid nodules. Management of Cowden's syndrome requires clinical examinations and investigations every 6 to 12 months from 18 years old or 5 years before the family's earliest age of cancer diagnosis and should focus on all clinical manifestations associated with PTEN mutations to identify early abnormal changes in skin, breasts, thyroid, endometrium, gut, and kidneys. Input from specialists across different disciplines is necessary.
CONCLUSIONS: We describe a man and his family with PTEN mutations who have increased risk of cancers and an unusually high number of offspring with autism spectrum disorder. Early recognition and close surveillance are vital in order to provide treatment and early screening for asymptomatic at-risk relatives.
Ezgu MC, Ozer MI, Dogan A, et al.Lhermitte-Duclos Disease in a Six-Year Old Child: A Rare Presentation.
Pediatr Neurosurg. 2018; 53(6):416-420 [PubMed
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Lhermitte-Duclos disease (LDD) is a rare, slow-growing, benign lesion of the cerebellum. It is often seen in the second and fourth decades. This disease is extremely rare in childhood. A 6-year-old girl presented with loss of balance. A mass lesion in the right cerebellum was detected by magnetic resonance imaging. The patient underwent surgical removal of the lesion, and the histological diagnosis was dysplastic gangliocytoma (LDD). The patient was discharged without complication, and her balance improved in the follow-up period. In this report, we present this rare occurrence in childhood and discuss the clinical course and management. LDD is very rare in early childhood and should be considered in the differential diagnosis of posterior fossa lesions.
Piekarski E, Pyatigorskaya N, Dormont D, et al.Increased 18F-FDG Uptake in Lhermitte-Duclos Disease With Cowden Syndrome Revealed by PET-MRI.
Clin Nucl Med. 2018; 43(10):e355-e356 [PubMed
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A 62-year-old woman, with the history of breast and colorectal cancer, presented intermittent diplopia. A cerebellar lesion was revealed by F-FDG PET-MRI without post-gadolinium enhancement, but with increased perfusion and strong F-FDG uptake. The diagnosis of Cowden syndrome with PTEN gene mutation, linked to higher risk of neoplasia and occurrence of hamartomatous lesions characteristic of the Lhermitte-Duclos disease (LDD), was confirmed by genetic investigation.
Severino-Freire M, Maza A, Kuentz P, et al.Severe gynaecological involvement in Proteus Syndrome.
Eur J Med Genet. 2019; 62(4):270-272 [PubMed
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Proteus Syndrome is a rare complex overgrowth syndrome. We report a young female patient with Proteus Syndrome due to AKT1 mutation c.49G > A (p.Glu17Lys), presenting with a severe gynaecological involvement which necessitated a complete hysterectomy and a left adnexectomy. Cases of gynecological involvements in Proteus Syndrome are rare, not well known by physicians while they can be potentially severe.
Garcias-Ladaria J, Cuadrado Rosón M, Pascual-López MEpidermal Nevi and Related Syndromes -- Part 1: Keratinocytic Nevi.
Actas Dermosifiliogr. 2018; 109(8):677-686 [PubMed
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Epidermal nevi are hamartomatous lesions derived from the epidermis and/or adnexal structures of the skin; they have traditionally been classified according to their morphology. New variants have been described in recent years and advances in genetics have contributed to better characterization of these lesions and an improved understanding of their relationship with certain extracutaneous manifestations. In the first part of this review article, we will look at nevi derived specifically from the epidermis and associated syndromes.
The PTEN gene encodes a master regulator protein that exerts essential functions both in the cytoplasm and in the nucleus. PTEN is mutated in the germline of both patients with heterogeneous tumor syndromic diseases, categorized as PTEN hamartoma tumor syndrome (PHTS), and a group affected with autism spectrum disorders (ASD). Previous studies have unveiled the functional heterogeneity of PTEN variants found in both patient cohorts, making functional studies necessary to provide mechanistic insights related to their pathogenicity. Here, we have functionally characterized a PTEN missense variant [c.49C>G; p.(Gln17Glu); Q17E] associated to both PHTS and ASD patients. The PTEN Q17E variant displayed partially reduced PIP3-catalytic activity and normal stability in cells, as shown using S. cerevisiae and mammalian cell experimental models. Remarkably, PTEN Q17E accumulated in the nucleus, in a process involving the PTEN N-terminal nuclear localization sequence. The analysis of additional germline-associated PTEN N-terminal variants illustrated the existence of a PTEN N-terminal region whose targeting in disease causes PTEN nuclear accumulation, in parallel with defects in PIP3-catalytic activity in cells. Our findings highlight the frequent occurrence of PTEN gene mutations targeting PTEN N-terminus whose pathogenicity may be related, at least in part, with the retention of PTEN in the nucleus. This could be important for the implementation of precision therapies for patients with alterations in the PTEN pathway.
Yehia L, Ni Y, Sesock K, et al.Unexpected cancer-predisposition gene variants in Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome patients without underlying germline PTEN mutations.
PLoS Genet. 2018; 14(4):e1007352 [PubMed
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Patients with heritable cancer syndromes characterized by germline PTEN mutations (termed PTEN hamartoma tumor syndrome, PHTS) benefit from PTEN-enabled cancer risk assessment and clinical management. PTEN-wildtype patients (~50%) remain at increased risk of developing certain cancers. Existence of germline mutations in other known cancer susceptibility genes has not been explored in these patients, with implications for different medical management. We conducted a 4-year multicenter prospective study of incident patients with features of Cowden/Cowden-like (CS/CS-like) and Bannayan-Riley-Ruvalcaba syndromes (BRRS) without PTEN mutations. Exome sequencing and targeted analysis were performed including 59 clinically actionable genes from the American College of Medical Genetics and Genomics (ACMG) and 24 additional genes associated with inherited cancer syndromes. Pathogenic or likely pathogenic cancer susceptibility gene alterations were found in 7 of the 87 (8%) CS/CS-like and BRRS patients and included MUTYH, RET, TSC2, BRCA1, BRCA2, ERCC2 and HRAS. We found classic phenotypes associated with the identified genes in 5 of the 7 (71.4%) patients. Variant positive patients were enriched for the presence of second malignant neoplasms compared to patients without identified variants (OR = 6.101, 95% CI 1.143-35.98, p = 0.035). Germline variant spectrum and frequencies were compared to The Cancer Genome Atlas (TCGA), including 6 apparently sporadic cancers associated with PHTS. With comparable overall prevalence of germline variants, the spectrum of mutated genes was different in our patients compared to TCGA. Intriguingly, we also found notable enrichment of variants of uncertain significance (VUS) in our patients (OR = 2.3, 95% CI 1.5-3.5, p = 0.0002). Our data suggest that only a small subset of PTEN-wildtype CS/CS-like and BRRS patients could be accounted for by germline variants in some of the known cancer-related genes. Thus, the existence of alterations in other and more likely non-classic cancer-associated genes is plausible, reflecting the complexity of these heterogeneous hereditary cancer syndromes.
Saito T, Nakane T, Narusawa M, et al.Giant umbilical cord and hypoglycemia in an infant with Proteus syndrome.
Am J Med Genet A. 2018; 176(5):1222-1224 [PubMed
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Proteus syndrome (PS) is characterized by the progressive, segmental, or patchy overgrowth of the skin, and other tissues. This is the first case report of recurrent severe insulin-independent hypoglycemia in an infant with PS. Somatic p.E17K of AKT1 mutation was confirmed. The patient also had a giant umbilical cord, which has not yet been reported in PS.
PTEN hamartoma tumor syndrome is a spectrum of disorders characterized by unique phenotypic features including multiple hamartomas caused by mutations of the tumor suppressor gene PTEN. Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome are representative diseases, and both have several common clinical features and differences. Because PTEN mutations are associated with an increased risk of malignancy including breast, thyroid, endometrial, and renal cancers, cancer surveillance is an important element of disease management. We report a germline mutation of the PTEN (c.723dupT, exon 7) identified in a young woman with a simultaneous occurrence of breast cancer, dermatofibrosarcoma protuberans, and follicular neoplasm. This case suggests that it is critical for clinicians to recognize the phenotypic features associated with these syndromes to accurately diagnose them and provide preventive care.
BACKGROUND: Cowden syndrome (CS) is a rare autosomal-dominant inherited disorder characterized by multiple hamartomas. While the hamartomas are benign, patients with CS have increased risk of osteosarcoma and of breast, thyroid, endometrial, soft-tissue and colonic neoplasms. Germline mutations of phosphatase and tensin homolog (PTEN) are implicated in CS and in the development of osteosarcoma. We report a patient with CS who presented with osteosarcoma, ganglioneuromatosis and a benign breast mass. Osteosarcoma, as presentation of CS, is rare (only one report in the English literature). Genomic DNA from the patient's peripheral blood was quantified by spectrophotometry, then underwent sequence enrichment, polymerase chain reaction and next-generation sequencing. Molecular analysis revealed a non-synonymous c.17_18delAA frameshift mutation in exon 1 of PTEN and a c.116G>T (p.R39L) missense mutation of serine/threonine kinase 11 (STK11) of unknown significance.
CONCLUSION: We report a patient with CS presenting with ganglioneuromatosis, benign breast mass and osteosarcoma, harboring a novel molecular alteration in PTEN which to our knowledge has not been previously reported.
Lopes S, Vide J, Moreira E, Azevedo FCowden syndrome: clinical case and a brief review.
Dermatol Online J. 2017; 23(8) [PubMed
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Cowden syndrome is a rare genodermatosis of autosomal dominant inheritance characterized by multiple hamartomas in several organs and an increased risk of malignancies. We present the case of a 53-year-old man with a history of benign and malignant thyroid disease, intestinal polyposis, and Chiari malformation. He had several trichilemmomas, papillomatosis of the oral cavity, macular pigmentation of the glans penis, among other clinical features suggestive of Cowden syndrome. Given the suspicion, genetic study was conducted and PTEN mutation was identified. Cowden syndrome affects 1:200,000 individuals. Mucocutaneous lesions are almost always present and there may be other typical features involving other organs, namely thyroid, colon, and brain. Mucocutaneous lesions may be the initial manifestation of this disorder and usually precede the onset of malignant lesions, making timely diagnosis essential for proper monitoring and screening.
Ghusayni R, Sachdev M, Gallentine W, et al.Hemimegalencephaly with Bannayan-Riley-Ruvalcaba syndrome.
Epileptic Disord. 2018; 20(1):30-34 [PubMed
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Hemimegalencephaly is known to occur in Proteus syndrome, but has not been reported, to our knowledge, in the other PTEN mutation-related syndrome of Bannayan-Riley-Ruvalcaba. Here, we report a patient with Bannayan-Riley-Ruvalcaba syndrome who also had hemimegalencephaly and in whom the hemimegalencephaly was evident well before presentation of the characteristic manifestations of Bannayan-Riley-Ruvalcaba syndrome. An 11-year-old boy developed drug-resistant focal seizures on the fifth day of life. MRI revealed left hemimegalencephaly. He later showed macrocephaly, developmental delay, athetotic quadriplegic cerebral palsy, and neuromuscular scoliosis. Freckling of the penis, which is characteristic of Bannayan-Riley-Ruvalcaba syndrome, was not present at birth but was observed at 9 years of age. Gene analysis revealed a c.510 T>G PTEN mutation. This patient and his other affected family members, his father and two siblings, were started on the tumour screening procedures recommended for patients with PTEN mutations. This case highlights the importance of early screening for PTEN mutations in cases of hemimegalencephaly not otherwise explained by another disorder, even in the absence of signs of Proteus syndrome or the full manifestations of Bannayan-Riley Ruvalcaba syndrome.
This article provides an overview of selected genetic skin conditions where multiple inherited cutaneous tumours are a central feature. Skin tumours that arise from skin structures such as hair, sweat glands and sebaceous glands are called skin appendage tumours. These tumours are uncommon, but can have important implications for patient care. Certain appendageal tumours, particularly when multiple lesions are seen, may indicate an underlying genetic condition. These tumours may not display clinical features that allow a secure diagnosis to be made, necessitating biopsy and dermatopathological assessment. Coupled with robust clinical assessment, biopsy findings can guide genetic testing as, increasingly, the causative genes are known for these conditions. Here we review illustrative examples of appendageal tumours and relevant advances made in genetic discovery, and suggest when referral to a geneticist may need to be considered.
Balci TB, Davila J, Lewis D, et al.Broad spectrum of neuropsychiatric phenotypes associated with white matter disease in PTEN hamartoma tumor syndrome.
Am J Med Genet B Neuropsychiatr Genet. 2018; 177(1):101-109 [PubMed
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White matter lesions have been described in patients with PTEN hamartoma tumor syndrome (PHTS). How these lesions correlate with the neurocognitive features associated with PTEN mutations, such as autism spectrum disorder (ASD) or developmental delay, has not been well established. We report nine patients with PTEN mutations and white matter changes on brain magnetic resonance imaging (MRI), eight of whom were referred for reasons other than developmental delay or ASD. Their clinical presentations ranged from asymptomatic macrocephaly with normal development/intellect, to obsessive compulsive disorder, and debilitating neurological disease. To our knowledge, this report constitutes the first detailed description of PTEN-related white matter changes in adult patients and in children with normal development and intelligence. We present a detailed assessment of the neuropsychological phenotype of our patients and discuss the relationship between the wide array of neuropsychiatric features and observed white matter findings in the context of these individuals.
Succinate dehydrogenase (SDH) is a heterotetrameric nuclear encoded mitochondrial protein complex which plays a role in the citric acid cycle and the electron transfer chain. Germline mutations in
Cowden syndrome is a rare autosomal dominant disorder characterized by multiple hamartomas of the ectoderm and brain. A 36-year-old Japanese man presented with right facial seizure during sleep and was admitted to our hospital. He showed cobblestoning over the tongue and palmar pitting but no neurological abnormalities while he was not having a seizure. Brain magnetic resonance imaging showed focal cortical dysplasia in the left frontal lobe. Electroencephalography showed sharp waves over the left frontal lesion. A genetic analysis revealed a novel mutation of PTEN. The administration of carbamazepine ended the seizures. This is the first Japanese case of Cowden syndrome with a novel PTEN gene mutation and cortical dysplasia.
Asoglu MR, Higgs A, Esin S, et al.The importance of prenatal 3-dimensional sonography in a case of a segmental overgrowth syndrome with unclear chromosomal microarray results.
J Clin Ultrasound. 2018; 46(5):351-354 [PubMed
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PIK3CA-related overgrowth spectrum, caused by mosaic mutations in the PIK3CA gene, is associated with regional or generalized asymmetric overgrowth of the body or a body part in addition to other clinical findings. Three-dimensional ultrasonography (3-D US) has the capability to display structural abnormalities in soft tissues or other organs, thereby facilitating identification of segmental overgrowth lesions. We present a case suspected of having a segmental overgrowth disorder based on 3-D US, whose chromosomal microarray result was abnormal, but apparently was not the cause of the majority of the fetus's clinical features.
Cowden syndrome is a rare autosomal dominant condition characterised by mucocutaneous hamartomas and, most importantly, predisposition to various extracutaneous benign and malignant tumours. This disorder is associated with a germline mutation in the phosphatase and tensin homologue gene, a tumour suppressor gene, located on 10q23 chromosome. The expressivity of this genodermatosis is highly variable, therefore many of the cases remain undiagnosed. Skin and mucous findings are very common in Cowden syndrome and may represent the initial clinical manifestation leading to the diagnosis. The authors describe a case of a 58-year-old man with multiple cutaneous sclerotic fibromas associated with a previously unrecognised Cowden syndrome.
Germline mutations in the tumor-suppressor gene PTEN predispose to subsets of Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome, and autism. Evidence-based classification of PTEN variants as either deleterious or benign is urgently needed for accurate molecular diagnosis and gene-informed genetic counseling. We studied 34 different germline PTEN intronic variants from 61 CS patients, characterized their PTEN mRNA processing, and analyzed PTEN expression and downstream readouts of P-AKT and P-ERK1/2. While we found that many mutations near splice junctions result in exon skipping, we also identified the presence of cryptic splicing that resulted in premature termination or a shift in isoform usage. PTEN protein expression is significantly lower in the group with splicing changes while P-AKT, but not P-ERK1/2, is significantly increased. Our observations of these PTEN intronic variants should contribute to the determination of pathogenicity of PTEN intronic variants and aid in genetic counseling.
Achatz MI, Porter CC, Brugières L, et al.Cancer Screening Recommendations and Clinical Management of Inherited Gastrointestinal Cancer Syndromes in Childhood.
Clin Cancer Res. 2017; 23(13):e107-e114 [PubMed
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Hereditary gastrointestinal cancer predisposition syndromes have been well characterized, but management strategies and surveillance remain a major challenge, especially in childhood. In October 2016, the American Association for Cancer Research organized the AACR Childhood Cancer Predisposition Workshop in which international experts in care of children with a hereditary risk of cancer met to define surveillance strategies and management of children with cancer predisposition syndromes. In this article, we review the current literature in polyposis syndromes that can be diagnosed in childhood and may be associated with an increased incidence of gastrointestinal neoplasms and other cancer types. These disorders include adenomatous polyposis syndromes (
Patients with overgrowth and complex vascular malformation syndromes, including Proteus syndrome have an increased risk of thromboembolism. Proteus syndrome is a mosaic, progressive overgrowth disorder involving vasculature, skin, and skeleton, and caused by a somatic activating mutation in AKT1. We conducted a comprehensive review of the medical histories and hematologic evaluations of 57 patients with Proteus syndrome to identify potential risk factors for thrombosis. We found that six of ten patients, who were deceased, died secondary to deep venous thrombosis and/or pulmonary embolism. Of the remaining 47 living patients, six had thromboembolic events that all occurred postoperatively and in an affected limb. Eleven of 21 patients had an abnormal hypercoagulable panel including Factor V Leiden heterozygotes, antithrombin III deficiency, positive lupus anticoagulant, or Protein C or S deficiencies. We observed that eight of 17 patients had an abnormal D-dimer level >0.5 mcg/dl, but deep venous thromboses occurred in only four of those with D-dimer >1.0 mcg/dl. We conclude that the predisposition to thrombosis is likely to be multifaceted with risk factors including vascular malformations, immobility, surgery, additional prothrombotic factors, and possible pathophysiologic effects of the somatic AKT1 mutation on platelet function or the vascular endothelium. The D-dimer test is useful as a screen for thromboembolism, although the screening threshold may need to be adjusted for patients with this disorder. We propose developing a registry to collect D-dimer and outcome data to facilitate adjustment of the D-dimer threshold for Proteus syndrome and related disorders, including PIK3CA-Related Overgrowth Spectrum.
Dominguez-Valentin M, Nakken S, Tubeuf H, et al.Potentially pathogenic germline CHEK2 c.319+2T>A among multiple early-onset cancer families.
Fam Cancer. 2018; 17(1):141-153 [PubMed
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To study the potential contribution of genes other than BRCA1/2, PTEN, and TP53 to the biological and clinical characteristics of multiple early-onset cancers in Norwegian families, including early-onset breast cancer, Cowden-like and Li-Fraumeni-like syndromes (BC, CSL and LFL, respectively). The Hereditary Cancer Biobank from the Norwegian Radium Hospital was used to identify early-onset BC, CSL or LFL for whom no pathogenic variants in BRCA1/2, PTEN, or TP53 had been found in routine diagnostic DNA sequencing. Forty-four cancer susceptibility genes were selected and analyzed by our in-house designed TruSeq amplicon-based assay for targeted sequencing. Protein- and RNA splicing-dedicated in silico analyses were performed for all variants of unknown significance (VUS). Variants predicted as the more likely to affect splicing were experimentally analyzed by minigene assay. We identified a CSL individual carrying a variant in CHEK2 (c.319+2T>A, IVS2), here considered as likely pathogenic. Out of the five VUS (BRCA2, CDH1, CHEK2, MAP3K1, NOTCH3) tested in the minigene splicing assay, only NOTCH3 c.14090C>T (p.Ser497Leu) showed a significant effect on RNA splicing, notably by inducing partial skipping of exon 9. Among 13 early-onset BC, CSL and LFL patients, gene panel sequencing identified a potentially pathogenic variant in CHEK2 that affects a canonical RNA splicing signal. Our study provides new information on genetic loci that may affect the risk of developing cancer in these patients and their families, demonstrating that genes presently not routinely tested in molecular diagnostic settings may be important for capturing cancer predisposition in these families.
Hansen-Kiss E, Beinkampen S, Adler B, et al.A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
J Med Genet. 2017; 54(7):471-478 [PubMed
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OBJECTIVE: It is recognised that 5% - 10 % of children with macrocephaly and autism spectrum disorder (ASD) and/or intellectual disability (ID) have a heterozygous pathogenic mutation in the
STUDY OBJECTIVES: We undertook a retrospective chart review of children (< 18 years) with pathogenic
RESULTS: Clinical and molecular data were collected and analysed for 47 patients with
CONCLUSIONS: This is the largest survey of clinical features in children with
Cowden syndrome (CS) is an inherited autosomal dominant disorder associated with germline pathogenic variants of the PTEN tumor suppressor gene. Its phenotypical expression is highly variable and the existence of patients with a CS suggestive phenotype without pathogenic PTEN variant may be related to genetic heterogeneity. In order to explore this hypothesis through the detection of potentially deleterious variants enabling us to identify a new candidate gene, we performed whole-exome sequencing (WES) in a series of 22 CS patients without detectable PTEN pathogenic variant using conventional methods for mutation screening. We failed to identify a novel candidate gene, but interestingly in two patients WES revealed the presence of two distinct, previously undescribed Alu insertions with the same break points in exon 5. These insertions were not found in a series of 35 breast carcinomas that showed a loss of PTEN expression without a detectable alteration of this gene. This study reveals the presence of a PTEN Alu insertion hotspot involved in CS, and suggests that undetected PTEN pathogenic variants could contribute to CS.
Chang F, Liu L, Fang E, et al.Molecular Diagnosis of Mosaic Overgrowth Syndromes Using a Custom-Designed Next-Generation Sequencing Panel.
J Mol Diagn. 2017; 19(4):613-624 [PubMed
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Recent studies have discovered a group of overgrowth syndromes, such as congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies (CLOVES) syndrome, Proteus syndrome, and megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome, are caused by somatic activating variants in genes involved in the phosphatidylinositol 3-kinase/AKT/mechanistic target of rapamycin pathway. Because of the low-abundance nature of these variants, Sanger sequencing often yields negative results. We have developed and validated a next-generation sequencing (NGS) panel that targets all known variants associated with these syndromes. Fifty cases, including two prenatal cases, were tested using the panel. A pathogenic variant in the PIK3CA, PIK3R2, or AKT1 gene was identified in 28 of the 50 cases with the variant allele frequencies ranging from 1.0% to 49.2%. These variants were only present in the affected tissues in most of the cases, demonstrating a causal role in the development of these diseases. In vitro cell culture showed significant enrichment of the cells harboring variant alleles, suggesting that these variants render growth advantages to mutant cells. Phenotype-genotype correlation analysis showed PIK3CA mutation hotspots at residues E542, E545, and H1047 are often associated with CLOVES syndrome, whereas PIK3CA G914R is preferentially related to MCAP. We thus demonstrate that NGS technology is highly sensitive for detecting low-level mosaicism and can facilitate clinical diagnosis of mosaic overgrowth syndromes in both prenatal and postnatal settings.
Jiang T, Wang J, Du J, et al.Lhermitte-Duclos Disease (Dysplastic Gangliocytoma of the Cerebellum) and Cowden Syndrome: Clinical Experience From a Single Institution with Long-Term Follow-Up.
World Neurosurg. 2017; 104:398-406 [PubMed
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BACKGROUND: Adult-onset Lhermitte-Duclos disease (LDD) and Cowden syndrome (CS) are considered a single phakomatosis that belongs to PTEN hamartoma tumor syndrome (PHTS) now. There is still controversy regarding the diagnosis and treatment. The authors describe the clinical features of LDD and CS with long-term follow up.
METHODS: From January 2001 to January 2017, 18 patients were admitted to the neurosurgery department of Beijing Tiantan Hospital. The authors analyzed the medical records of each patient and followed every case.
RESULTS: Seventeen of 18 patients underwent surgery to remove the tumor. The results of pathologic analysis revealed LDD. There was obvious enhancement on magnetic resonance imaging (MRI) in 2 patients who received gamma knife and radiotherapy before surgery. During surgery, it is difficult to determine the exact margin. Tumors were removed gross totally in 9 patients, partially in 6 patients, and only subtotally in 2 patients. CS was diagnosed in 11 patients. Two patients received DNA analysis, revealing heterozygous mutation of exon 5 in an 11-year-old girl. There was no recurrence of the tumor during follow-up.
CONCLUSIONS: LDD has the unique appearance on T2-weighted MRI. The most difficult aspect of surgery is determining the actual margins of the tumor. Total resection is difficult in some patients. There was no tumor recurrence after long-term follow-up in our case series. For pediatric LDD patients, DNA analysis should be performed to rule out CS.