DNA methylation episignature, extension of the clinical features, and comparative epigenomic profiling of Hao-Fountain syndrome caused by variants in USP7.

PURPOSE: Hao-Fountain syndrome (HAFOUS) is a neurodevelopmental disorder caused by pathogenic variants in USP7. HAFOUS is characterized by developmental delay, intellectual disability, speech delay, behavioral abnormalities, autism spectrum disorder, seizures, hypogonadism, and mild dysmorphic features. We investigated the phenotype of 18 participants with HAFOUS and performed DNA methylation (DNAm) analysis, aiming to generate a diagnostic biomarker. Furthermore, we performed comparative analysis with known episignatures to gain more insight into the molecular pathophysiology of HAFOUS. METHODS: We assessed genomic DNAm profiles of 18 individuals with pathogenic variants and variants of uncertain significance (VUS) in USP7 to map and validate a specific episignature. The comparison between the USP7 cohort and 56 rare genetic disorders with earlier reported DNAm episignatures was performed with statistical and functional correlation. RESULTS: We mapped a sensitive and specific DNAm episignature for pathogenic variants in USP7 and utilized this to reclassify the VUS. Comparative epigenomic analysis showed evidence of HAFOUS similarity to a number of other rare genetic episignature disorders. CONCLUSION: We discovered a sensitive and specific DNAm episignature as a robust diagnostic biomarker for HAFOUS that enables VUS reclassification in USP7. We also expand the phenotypic spectrum of 9 new and 5 previously reported individuals with HAFOUS.

5q35 duplication syndrome: Narrowing the critical region on the distal side and further evidence of intrafamilial variability and expression.

The key features of patients with a microduplication 5q35.2q35.3 (including the NSD1 gene) are short stature, microcephaly, mild developmental delay, behavioral problems, digital anomalies and congenital anomalies of internal organs. This core phenotype can be viewed as the reversed phenotype of Sotos syndrome, which is caused by a microdeletion in the same chromosomal region or a pathogenic variant in the NSD1 gene, and includes tall stature and macrocephaly, developmental delay, and epilepsy. Here, we report on a patient and his mother, both with a 5q35.2q35.3 duplication, adding a fifth family to the recently published overview of 39 patients of Quintero-Rivera et al. Our patient had several congenital anomalies, intrauterine growth restriction with a persisting short stature, while his mother was only mildly affected with decreased growth parameters. In addition, he had hemophagogocytic lymphohistiocytosis (HLH) triggered by Haemophilus influenzae and was recently diagnosed with Ewing sarcoma. Our cases carry the smallest duplication published (ca 332 kb, arr[hg19] 5q35.2q35.3(176493106-176824785)x3) further narrowing the distal side of the critical region of the 5q35.2q35.3 duplication. Besides broadening the clinical phenotypic spectrum, our report indicates that the 5q35.2q35.3 microduplication also shows a large intra-familial variability and expression.

Lymphedema as first clinical presentation of Cantu Syndrome: reversed phenotyping after identification of gain-of-function variant in ABCC9.

Cantu Syndrome (CS), [OMIM #239850] is characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly. CS is caused by gain-of-function (GOF) variants in the KCNJ8 or ABCC9 genes that encode pore-forming Kir6.1 and regulatory SUR2 subunits of ATP-sensitive potassium (KATP) channels. Many subjects with CS also present with the complication of lymphedema. A previously uncharacterized, heterozygous ABCC9 variant, p.(Leu1055_Glu1058delinsPro), termed indel1055, was identified in an individual diagnosed with idiopathic lymphedema. The variant was introduced into the equivalent position of rat SUR2A, and inside-out patches were used to characterize the KATP channels formed by Kir6.2 and WT or mutant SUR2A subunits coexpressed in Cosm6 cells. The indel1055 variant causes gain-of-function of the channel, with an increase of the IC50 for ATP inhibition compared to WT. Retrospective consideration of this individual reveals clear features of Cantu Syndrome. An additional heterozygous ABCC9 variant, p.(Ile419Thr), was identified in a second individual diagnosed with lymphedema. In this case, there were no additional features consistent with CS, and the properties of p.(Ile416Thr) (the corresponding mutation in rat SUR2A)--containing channels were not different from WT. This proof-of-principle study shows that idiopathic lymphedema may actually be a first presentation of otherwise unrecognized Cantu Syndrome, but molecular phenotyping of identified variants is necessary to confirm relevance.

Terminal osseous dysplasia with pigmentary defects and cardiomyopathy caused by a novel FLNA variant.

Terminal osseous dysplasia with pigmentary defects (TODPD), also known as digitocutaneous dysplasia, is one of the X-linked filaminopathies caused by a variety of FLNA-variants. TODPD is characterized by skeletal defects, skin fibromata and dysmorphic facial features. So far, only a single recurrent variant (c.5217G>A;p.Val1724_Thr1739del) in FLNA has found to be responsible for TODPD. We identified a novel c.5217+5G>C variant in FLNA in a female proband with skeletal defects, skin fibromata, interstitial lung disease, epilepsy, and restrictive cardiomyopathy. This variant causes mis-splicing of exon 31 predicting the production of a FLNA-protein with an in-frame-deletion of 16 residues identical to the miss-splicing-effect of the recurrent TODPD c.5217G>A variant. This mis-spliced transcript was explicitly detected in heart tissue, but was absent from blood, skin, and lung. X-inactivation analyses showed extreme skewing with almost complete inactivation of the mutated allele (>90%) in these tissues, except for heart. The mother of the proband, who also has fibromata and skeletal abnormalities, is also carrier of the FLNA-variant and was diagnosed with noncompaction cardiomyopathy after cardiac screening. No other relevant variants in cardiomyopathy-related genes were found. Here we describe a novel variant in FLNA (c.5217+5G>C) as the second pathogenic variant responsible for TODPD. Cardiomyopathy has not been described as a phenotypic feature of TODPD before.

Heterozygous Variants in KDM4B Lead to Global Developmental Delay and Neuroanatomical Defects.

KDM4B is a lysine-specific demethylase with a preferential activity on H3K9 tri/di-methylation (H3K9me3/2)-modified histones. H3K9 tri/di-demethylation is an important epigenetic mechanism responsible for silencing of gene expression in animal development and cancer. However, the role of KDM4B on human development is still poorly characterized. Through international data sharing, we gathered a cohort of nine individuals with mono-allelic de novo or inherited variants in KDM4B. All individuals presented with dysmorphic features and global developmental delay (GDD) with language and motor skills most affected. Three individuals had a history of seizures, and four had anomalies on brain imaging ranging from agenesis of the corpus callosum with hydrocephalus to cystic formations, abnormal hippocampi, and polymicrogyria. In mice, lysine demethylase 4B is expressed during brain development with high levels in the hippocampus, a region important for learning and memory. To understand how KDM4B variants can lead to GDD in humans, we assessed the effect of KDM4B disruption on brain anatomy and behavior through an in vivo heterozygous mouse model (Kdm4b+/-), focusing on neuroanatomical changes. In mutant mice, the total brain volume was significantly reduced with decreased size of the hippocampal dentate gyrus, partial agenesis of the corpus callosum, and ventriculomegaly. This report demonstrates that variants in KDM4B are associated with GDD/ intellectual disability and neuroanatomical defects. Our findings suggest that KDM4B variation leads to a chromatinopathy, broadening the spectrum of this group of Mendelian disorders caused by alterations in epigenetic machinery.

Dihydropyrimidine Dehydrogenase Deficiency: Homozygosity for an Extremely Rare Variant in DPYD due to Uniparental Isodisomy of Chromosome 1.

Dihydropyrimidine dehydrogenase (DPD) deficiency is a rare autosomal recessive disorder of the pyrimidine degradation pathway and can lead to intellectual disability, motor retardation, and seizures. Genetic variations in DPYD have also emerged as predictive risk factors for severe toxicity in cancer patients treated with fluoropyrimidines. We recently observed a child born to non-consanguineous parents, who demonstrated seizures, cognitive impairment, language delay, and MRI abnormalities and was found to have marked thymine-uraciluria. No residual DPD activity could be detected in peripheral blood mononuclear cells. Molecular analysis showed that the child was homozygous for the very rare c.257C > T (p.Pro86Leu) variant in DPYD. Functional analysis of the recombinantly expressed DPD mutant showed that the DPD mutant carrying the p.Pro86Leu did not possess any residual DPD activity. Carrier testing in parents revealed that the father was heterozygous for the variant but unexpectedly the mother did not carry the variant. Microsatellite repeat testing with markers covering chromosome 1 showed that the DPD deficiency in the child is due to paternal uniparental isodisomy. Our report thus extends the genetic spectrum underlying DPYD deficiency.

Van Maldergem syndrome and Hennekam syndrome: Further delineation of allelic phenotypes.

Biallelic variants in FAT4 are associated with the two disorders, Van Maldergem syndrome (VMS) (n = 11) and Hennekam syndrome (HS) (n= 40). Both conditions are characterized by a typical facial gestalt and mild to moderate intellectual disability, but differ in the occurrence of neonatal hypotonia and feeding problems, hearing loss, tracheal anomalies, and osteopenia in VMS, and lymphedema in HS. VMS can be caused by autosomal recessive variants in DCHS1 as well, and HS can also be caused by autosomal recessive variants in CCBE1 and ADAMTS3. Here we report two siblings with VMS and one girl with HS, all with FAT4 variants, and provide an overview of the clinical findings in all patients reported with FAT4 variants. Our comparison of the complete phenotypes of patients with VMS and HS indicates a resemblance of several signs, but differences in several other main signs and symptoms, each of marked importance for affected individuals.

Clues for Polygenic Inheritance of Pituitary Stalk Interruption Syndrome From Exome Sequencing in 20 Patients.

Context: Pituitary stalk interruption syndrome (PSIS) consists of a small/absent anterior pituitary lobe, an interrupted/absent pituitary stalk, and an ectopic posterior pituitary lobe. Mendelian forms of PSIS are detected infrequently (<5%), and a polygenic etiology has been suggested. GLI2 variants have been reported at a relatively high frequency in PSIS. Objective: To provide further evidence for a non-Mendelian, polygenic etiology of PSIS. Methods: Exome sequencing (trio approach) in 20 patients with isolated PSIS. In addition to searching for (potentially) pathogenic de novo and biallelic variants, a targeted search was performed in a panel of genes associated with midline brain development (223 genes). For GLI2 variants, both (potentially) pathogenic and relatively rare variants (<5% in the general population) were studied. The frequency of GLI2 variants was compared with that of a reference population. Results: We found four additional candidate genes for isolated PSIS (DCHS1, ROBO2, CCDC88C, and KIF14) and one for syndromic PSIS (KAT6A). Eleven GLI2 variants were present in six patients. A higher frequency of a combination of two GLI2 variants (M1352V + D1520N) was found in the study group compared with a reference population (10% vs 0.68%). (Potentially) pathogenic variants were identified in genes associated with midline brain anomalies, including holoprosencephaly, hypogonadotropic hypogonadism, and absent corpus callosum and in genes involved in ciliopathies. Conclusion: Combinations of variants in genes associated with midline brain anomalies are frequently present in PSIS and sustain the hypothesis of a polygenic cause of PSIS.

Oral-facial-digital syndrome type 1 in males: Congenital heart defects are included in its phenotypic spectrum.

Oral-facial-digital syndrome type 1 (OFD1; OMIM# 311200) is an X-linked dominant ciliopathy caused by mutations in the OFD1 gene. This condition is characterized by facial anomalies and abnormalities of oral tissues, digits, brain, and kidneys. Almost all affected patients are female, as OFD1 is presumed to be lethal in males, mostly in the first or second trimester of pregnancy. Live born males with OFD1 are a rare occurrence, with only five reported patients to date. In four patients the presence of a congenital heart defect (CHD) was observed. Here, we report an affected male fetus with a hemizygous de novo mutation in OFD1 (c.2101C>T; p.(Gln701*)). Ultrasound examination demonstrated severe hydrocephalus, a hypoplastic cerebellum and a hypoplastic left ventricle of the heart. The pregnancy was terminated at 16 weeks of gestation because of poor prognosis. Post-mortem examination of the fetus confirmed severe hypoplasia of the left ventricle of the heart. We emphasize that CHDs should be included in the phenotypic spectrum of OFD1 in males. This justifies molecular analysis of OFD1 when CHD is encountered prenatally in combination with one or more phenotypic features previously described in the OFD1 gene alteration spectrum. The underlying pathogenesis of CHD in OFD1 (and other ciliopathies) probably involves dysfunction of the primary cilia regarding coordination of left-right signalling during early heart development. Whether these CHDs wholly or partly result from defective left right signalling, in which different types of cilia are known to play a critical role, remains a topic of research.

Humoral Immunodeficiency with Hypotonia, Feeding Difficulties, Enteropathy, and Mild Eczema Caused by a Classical FOXP3 Mutation.

We describe here the case of a boy who presented with pulmonary infections, feeding difficulties due to velopharyngeal insufficiency and gastroesophageal reflux, myopathy, and hypotonia soon after birth. Later, he was also found to have an elevated immunoglobulin (Ig) E and mild eczema and was diagnosed with inflammatory bowel disease. Further immunological screening at the age of 7 years showed low B and NK cell numbers but normal CD4+ and CD8+ T cells and notably, normal numbers of CD4+ regulatory T (Treg) cells. Serum IgG, IgA, and IgM were low to normal, but he had a deficient response to a pneumococcal polysaccharide vaccine and thus a humoral immunodeficiency. To our surprise, whole exome sequencing revealed a mutation in forkhead box protein 3 (FOXP3), encoding an essential transcription factor for the development and function of Treg cells. This classical mutation is associated with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. Further in vitro studies indeed showed defective function of Treg cells despite normal FOXP3 protein expression and nuclear localization. The boy underwent hematopoietic stem cell transplantation at 11 years of age and despite the temporary development of diabetes while on prednisone is now doing much better, IgE levels have declined, and his fatigue has improved. This case illustrates that a classical pathogenic mutation in FOXP3 can lead to a clinical phenotype where the diagnosis of IPEX syndrome was never considered because of the lack of diabetes and the presence of only mild eczema, in addition to the normal Treg cell numbers and FOXP3 expression.

Mutations in EXTL3 Cause Neuro-immuno-skeletal Dysplasia Syndrome.

EXTL3 regulates the biosynthesis of heparan sulfate (HS), important for both skeletal development and hematopoiesis, through the formation of HS proteoglycans (HSPGs). By whole-exome sequencing, we identified homozygous missense mutations c.1382C>T, c.1537C>T, c.1970A>G, and c.2008T>G in EXTL3 in nine affected individuals from five unrelated families. Notably, we found the identical homozygous missense mutation c.1382C>T (p.Pro461Leu) in four affected individuals from two unrelated families. Affected individuals presented with variable skeletal abnormalities and neurodevelopmental defects. Severe combined immunodeficiency (SCID) with a complete absence of T cells was observed in three families. EXTL3 was most abundant in hematopoietic stem cells and early progenitor T cells, which is in line with a SCID phenotype at the level of early T cell development in the thymus. To provide further support for the hypothesis that mutations in EXTL3 cause a neuro-immuno-skeletal dysplasia syndrome, and to gain insight into the pathogenesis of the disorder, we analyzed the localization of EXTL3 in fibroblasts derived from affected individuals and determined glycosaminoglycan concentrations in these cells as well as in urine and blood. We observed abnormal glycosaminoglycan concentrations and increased concentrations of the non-sulfated chondroitin disaccharide D0a0 and the disaccharide D0a4 in serum and urine of all analyzed affected individuals. In summary, we show that biallelic mutations in EXTL3 disturb glycosaminoglycan synthesis and thus lead to a recognizable syndrome characterized by variable expression of skeletal, neurological, and immunological abnormalities.

Shwachman-Diamond syndrome presenting with early ichthyosis, associated dermal and epidermal intracellular lipid droplets, hypoglycemia, and later distinctive clinical SDS phenotype.

Shwachman-Diamond syndrome (SDS) is a recessive ribosomopathy, characterized by bone marrow failure and exocrine pancreatic insufficiency (ePI) often associated with neurodevelopmental and skeletal abnormalities. The aim of this report is to describe a SDS patient with early ichthyosis associated with dermal and epidermal intracellular lipid droplets (iLDs), hypoglycemia and later a distinctive clinical SDS phenotype. At 3 months of age, she had ichthyosis, growth retardation, and failure to thrive. She had not cytopenia. Ultrasonography (US) showed pancreatic diffuse high echogenicity. Subsequently fasting hypoketotic hypoglycemia occurred without permanent hepatomegaly or hyperlipidemia. Continuous gavage feeding was followed by clinical improvement including ichthyosis and hypoglycemia. After 14 months of age, she developed persistent neutropenia and ePI consistent with SDS. The ichthyotic skin biopsy, performed at 5 months of age, disclosed iLDs in all epidermal layers, in melanocytes, eccrine sweat glands, Schwann cells and dermal fibroblasts. These iLDs were reminiscent of those described in Dorfman-Chanarin syndrome (DCS) or Wolman's disease. Both LIPA and CGI-58 analysis did not revealed pathogenic mutation. By sequencing SBDS, a compound heterozygous for a previously reported gene mutation (c.258 + 2T>C) and a novel mutation (c.284T>G) were found. Defective SBDS may hypothetically interfere as in DCS, with neutral lipid metabolism and play a role in the SDS phenotype such as ichthyosis with dermal and epidermal iLDs and hypoglycemia. This interference with neutral lipid metabolism must most likely occur in the cytoplasm compartment as in DCS and not in the lysosomal compartment as in Wolman's disease. © 2016 Wiley Periodicals, Inc.

Hennekam syndrome can be caused by FAT4 mutations and be allelic to Van Maldergem syndrome.

The Hennekam lymphangiectasia-lymphedema syndrome is a genetically heterogeneous disorder. It can be caused by mutations in CCBE1 which are found in approximately 25 % of cases. We used homozygosity mapping and whole-exome sequencing in the original HS family with multiple affected individuals in whom no CCBE1 mutation had been detected, and identified a homozygous mutation in the FAT4 gene. Subsequent targeted mutation analysis of FAT4 in a cohort of 24 CCBE1 mutation-negative Hennekam syndrome patients identified homozygous or compound heterozygous mutations in four additional families. Mutations in FAT4 have been previously associated with Van Maldergem syndrome. Detailed clinical comparison between van Maldergem syndrome and Hennekam syndrome patients shows that there is a substantial overlap in phenotype, especially in facial appearance. We conclude that Hennekam syndrome can be caused by mutations in FAT4 and be allelic to Van Maldergem syndrome.

Aberrant humoral immune reactivity in DOCK8 deficiency with follicular hyperplasia and nodal plasmacytosis.

Mutations in the DOCK8 gene define the most common form of autosomal-recessive Hyper-IgE-syndrome (AR-HIES/OMIM#243700). In a patient with extensive molluscum contagiosum lesions, a homozygous DOCK8 gene deletion was demonstrated. In-vivo 18-FDG uptake showed multiple non-enlarged lymph nodes without uptake in the spleen. Lymph node biopsies for subsequent immunohistochemistry showed clear differences with the mouse model of DOCK8 deficiency in which these mice show no GCs. Unexpectedly, the patient's lymph nodes demonstrated lymphocyte polyclonality, follicular hyperplasia and an unusual IgE(+) plasma cell expansion. In contrast, the proliferative capacity of circulating B-cells was almost absent with little in-vitro Ig production or plasmablast formation. Also the T-cell proliferation indicated a partial defect. Hematopoietic stem cell transplantation (HSCT) was performed resulting in the disappearance of the molluscum contagiosum lesions. In sum, DOCK8 deficiency results in defective antibody responses and undirected plasma cell expansion in the lymph nodes, as part of a combined immunodeficiency cured by HSCT.

A STAT3 mutation in hyper-immunoglobulin E syndrome: A case report.

Hyper-immunoglobulin E syndrome (HIES) is a rare immunologic disorder. This syndrome is caused by mutations in signal transducer and activator of transcription 3 gene. The described case report showed clinical HIES features such as recurrent bacterial pneumonia, lung cysts, characteristic facial features and a newborn dermatitis. We found a clinical features score of 35 and a positive family history, which, together, made a HIES diagnosis very probable. During DNA analysis, a new, formerly unknown, 1067C→G (p.P356R) mutation, with reference sequence NM_139276.2, was found in the DNA binding site of the STAT3 gene. Both the child and his mother were affected. Thus, this family is affected by the autosomal dominant, HIES. This case report reveals a formerly unknown mutation, 1067C→G (p.P356R) in this gene.

Increase in central striatal dopamine transporters in patients with Shwachman-Diamond syndrome: additional evidence of a brain phenotype.

Patients with Shwachman-Diamond syndrome (SDS) do not only experience well-described physical features like skeletal abnormalities and hematological dysfunctions, but recent studies also suggested attention and working memory deficits in SDS. Indeed, a recent structural magnetic resonance imaging (MRI) study demonstrated smaller brain regions in SDS. Regarding attention and working memory, however, an important role for the neurotransmitter dopamine is well established. Therefore, in this study we assessed in vivo dopamine transporters (DATs; a specific marker of dopaminergic cells expressed in nerve terminals) and performed structural MRI in SDS. In 6 and 5 young SDS patients, respectively, we were able to acquire DAT single photon emission computed tomography (SPECT) and MRI examinations, and the data were compared to age-matched control data. Striatal DAT binding was significantly increased in SDS patients as compared to controls. In addition, we observed significantly smaller volumes particularly posteriorly and caudally located in the brain: the corpus callosum, brainstem, and cerebellum. Also the thalamus was smaller in SDS patients than in controls. In conclusion, our data replicate earlier findings on smaller brain regions in SDS. In addition, our novel molecular imaging data suggest that SDS patients may have a dysregulated dopaminergic system. These findings may be of relevance to increase our understanding of behavioral and cognitive deficits in SDS.

Phylogenetic and physicochemical analyses enhance the classification of rare nonsynonymous single nucleotide variants in type 1 and 2 long-QT syndrome.

BACKGROUND: Hundreds of nonsynonymous single nucleotide variants (nsSNVs) have been identified in the 2 most common long-QT syndrome-susceptibility genes (KCNQ1 and KCNH2). Unfortunately, an ≈3% BACKGROUND: and KCNH2 nsSNVs amongst healthy individuals complicates the ability to distinguish rare pathogenic mutations from similarly rare yet presumably innocuous variants. METHODS AND RESULTS: In this study, 4 tools [(1) conservation across species, (2) Grantham values, (3) sorting intolerant from tolerant, and (4) polymorphism phenotyping] were used to predict pathogenic or benign status for nsSNVs identified across 388 clinically definite long-QT syndrome cases and 1344 ostensibly healthy controls. From these data, estimated predictive values were determined for each tool independently, in concert with previously published protein topology-derived estimated predictive values, and synergistically when ≥3 tools were in agreement. Overall, all 4 tools displayed a statistically significant ability to distinguish between case-derived and control-derived nsSNVs in KCNQ1, whereas each tool, except Grantham values, displayed a similar ability to differentiate KCNH2 nsSNVs. Collectively, when at least 3 of the 4 tools agreed on the pathogenic status of C-terminal nsSNVs located outside the KCNH2/Kv11.1 cyclic nucleotide-binding domain, the topology-specific estimated predictive value improved from 56% to 91%. CONCLUSIONS: Although in silico prediction tools should not be used to predict independently the pathogenicity of a novel, rare nSNV, our results support the potential clinical use of the synergistic utility of these tools to enhance the classification of nsSNVs, particularly for Kv11.1's difficult to interpret C-terminal region.

A 46,XY female DSD patient with bilateral gonadoblastoma, a novel SRY missense mutation combined with a WT1 KTS splice-site mutation.

Patients with Disorders of Sex Development (DSD), especially those with gonadal dysgenesis and hypovirilization are at risk of developing malignant type II germ cell tumors/cancer (GCC) (seminoma/dysgerminoma and nonseminoma), with either carcinoma in situ (CIS) or gonadoblastoma (GB) as precursor lesion. In 10-15% of 46,XY gonadal dysgenesis cases (i.e., Swyer syndrome), SRY mutations, residing in the HMG (High Mobility Group) domain, are found to affect nuclear transport or binding to and bending of DNA. Frasier syndrome (FS) is characterized by gonadal dysgenesis with a high risk for development of GB as well as chronic renal failure in early adulthood, and is known to arise from a splice site mutation in intron 9 of the Wilms' tumor 1 gene (WT1). Mutations in SRY as well as WT1 can lead to diminished expression and function of SRY, resulting in sub-optimal SOX9 expression, Sertoli cell formation and subsequent lack of proper testicular development. Embryonic germ cells residing in this unfavourable micro-environment have an increased risk for malignant transformation. Here a unique case of a phenotypically normal female (age 22 years) is reported, presenting with primary amenorrhoea, later diagnosed as hypergonadotropic hypogonadism on the basis of 46,XY gonadal dygenesis with a novel missense mutation in SRY. Functional in vitro studies showed no convincing protein malfunctioning. Laparoscopic examination revealed streak ovaries and a normal, but small, uterus. Pathological examination demonstrated bilateral GB and dysgerminoma, confirmed by immunohistochemistry. Occurrence of a delayed progressive kidney failure (focal segmental glomerular sclerosis) triggered analysis of WT1, revealing a pathogenic splice-site mutation in intron 9. Analysis of the SRY gene in an additional five FS cases did not reveal any mutations. The case presented shows the importance of multi-gene based diagnosis of DSD patients, allowing early diagnosis and treatment, thus preventing putative development of an invasive cancer.

PTEN hamartoma tumor syndrome and Gorham-Stout phenomenon.

PTEN: hamartoma tumor syndrome (PHTS) is a group of syndromes caused by mutations in PTEN. Gorham-Stout phenomenon (GSP) is a rare condition characterized by proliferation of vascular structures in bones, resulting in progressive osteolysis. Here we present a 1-year-old boy with PHTS and GSP. The lesion that later proved to be GSP was evident from the age of 4 months, and became symptomatic at the age of 1 year. Eventually, he developed a fatal chylothorax. Mutation analysis revealed a germline heterozygous mutation c.517 C>T (p.Arg173Cys) in exon 6 of PTEN. Analysis of the lymphatic malformation (LM) tissue revealed no loss of heterozygosity (LOH) nor a second, somatic PTEN mutation of the remaining wild type allele. The germline p.Arg173Cys mutation was also present in the mother and the propositus' younger sister and brother. Further molecular work-up showed a heterozygous variant c.2180C>T (p.Ala727Val) FLT4 in the LM tissue, which was also present in the germline of mother and two siblings. GSP has not been reported before in a patient with a PTEN mutation. Up to this date, this mutation is the only genetic defect possibly involved in the etiology of GSP which is plausible given the known function of PTEN in angiogenic signaling.

KCNQ1OT1 hypomethylation: a novel disguised genetic predisposition in sporadic pediatric adrenocortical tumors?

Pediatric adrenal tumors, other than neuroblastoma, are rare and can be associated with a genetic predisposition. In this report we describe two patients with an isolated and apparently sporadic adrenocortical tumor; one girl with a carcinoma, the other girl with an adenoma. In both patients genetic screening revealed hypomethylation of the KCNQ1OT1 gene, well-known for its association with the Beckwith-Wiedemann syndrome. This represents a likely novel genetic predisposition in patients with adrenocortical tumors without clear phenotypic features of the Beckwith-Wiedemann syndrome.