Two Novel Monoallelic Calreticulin Mutations in a Patient With Essential Thrombocythemia.

Recently, mutations have been identified in the calreticulin (CALR) gene in JAK2 or myeloproliferative leukemia negative patients with myeloproliferative neoplasm. A 49-year-old male patient with incidental thrombocytosis was investigated for CALR mutation by direct sequencing method. The patient carried two novel monoallelic somatic mutations, the L367fs*52 and the p.R368W in the CALR gen, which resulted in a novel C-terminal sequence. The absent endoplasmatic reticulum retention signal in the mutant CALR results in an altered subcellular localization of the mutant protein. The new positively charged C-terminal domain has an importance for oncogenicity, effecting different signaling pathways, activating the cytokine-independent growth of the cells and down-regulating the apoptotic signaling. But the new, alternative C-terminal domain offers an opportunity for immunologic therapy as it represents a cancer-specific epitope.

Identification of the first multi-exonic WDR72 deletion in isolated amelogenesis imperfecta, and generation of a WDR72-specific copy number screening tool.

Amelogenesis imperfecta (AI) is a clinically and genetically heterogeneous disorder of tooth development which is due to aberrant deposition or composition of enamel. Both syndromic and isolated forms exist; they may be inherited in an X-linked, autosomal recessive, or autosomal dominant manner. WDR72 is one of ten currently known genes for recessive isolated AI; nine WDR72 mutations affecting single nucleotides have been described to date. Based on whole exome sequencing in a large consanguineous AI pedigree, we obtained evidence for presence of a multi-exonic WDR72 deletion. A home-made multiplex ligation-dependent probe amplification assay was used to confirm the aberration, to narrow its extent, and to identify heterozygous carriers. Our study extends the mutational spectrum for WDR72 to include large deletions, and supports a relevance of the previously proposed loss-of-function mechanism. It also introduces an easy-to-use and highly sensitive tool for detecting WDR72 copy number alterations.

Recurrence of split hand/foot malformation, cleft lip/palate, and severe urogenital abnormalities due to germline mosaicism for TP63 mutation.

We describe two sibling fetuses with urogenital abnormalities detected by prenatal ultrasound, in which post-delivery examination showed split hand and foot malformation, and bilateral cleft lip and palate. These findings are consistent with ectrodactyly-ectodermal dysplasia-cleft lip with or without cleft palate syndrome (EEC). Both fetuses were found to have the same missense mutation in TP63 (c.1051G > A; p.D351N). Parental clinical examinations and lymphocyte DNA analyses were normal. This report illustrates the potential severity of urogenital defects in TP63-related disorders, which may be detectable with fetal ultrasonography. It highlights the need to counsel for the possibility of germline mosaicism in TP63-associated disorders. © 2016 Wiley Periodicals, Inc.

Ectodermal Defects and Anal Atresia in a Child with a TP63 Mutation--Expanding the Phenotypic Spectrum.

Ectodermal dysplasias caused by mutations in the TP63 gene comprise a group of disorders characterized by a spectrum of ectodermal changes, orofacial clefting, and split hand or foot malformation. We report on a boy with a mutation located in the DNA-binding domain of the TP63 gene with atypical phenotype. These data provide additional evidence of the great variability seen in TP63-related disorders and further delineation of genotype-phenotype correlations.

Monozygotic twins with neurofibromatosis type 1 (NF1) display differences in methylation of NF1 gene promoter elements, 5' untranslated region, exon and intron 1.

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder caused by heterozygotic inactivation of the NF1 tumor suppressor gene at 17q11.2. The associated phenotypes are highly variable, and modifying genes have been proposed to explain at least in part the intriguing expressivity. Given that haploinsufficiency of the NF1 gene product neurofibromin is responsible for some of the clinical manifestations, variations in expression of the wildtype NF1 allele might modify the phenotype. We therefore investigated epigenetic molecular modifications that could result in variable expression of the normal NF1 allele. To exclude confounding by DNA sequence variations, we analyzed monozygotic twin pairs with NF1 who presented with several discordant features. We fine-mapped the methylation pattern of a nearly 1 kb NF1 promoter region in lymphocytes of 8 twin pairs. All twin pairs showed significant intra-pair differences in methylation, especially of specific promoter subregions such as 5'UTR, exon 1 and intron 1 (+7 to +622), transcription factor binding sites and promoter elements like NF1HCS. Furthermore, we detected significant intra-pair differences in cytosine methylation for the region from -249 to -234 with regard to discordance for optic glioma with a higher grade of methylation in glioma cases. In conclusion, our findings of epigenetic differences of the NF1 promoter in leukocytes within mono zygotic twin pairs may serve as a proof of principle for other tissues. The results point towards a role of methylation patterns of the normal NF1 allele for expression differences and for modification of the NF1 phenotype.

Deletions of the RUNX2 gene are present in about 10% of individuals with cleidocranial dysplasia.

Cleidocranial Dysplasia (CCD) is an autosomal dominant skeletal disorder characterized by hypoplastic or absent clavicles, increased head circumference, large fontanels, dental anomalies, and short stature. Hand malformations are also common. Mutations in RUNX2 cause CCD, but are not identified in all CCD patients. In this study we screened 135 unrelated patients with the clinical diagnosis of CCD for RUNX2 mutations by sequencing analysis and demonstrated 82 mutations 48 of which were novel. By quantitative PCR we screened the remaining 53 unrelated patients for copy number variations in the RUNX2 gene. Heterozygous deletions of different size were identified in 13 patients, and a duplication of the exons 1 to 4 of the RUNX2 gene in one patient. Thus, heterozygous deletions or duplications affecting the RUNX2 gene may be present in about 10% of all patients with a clinical diagnosis of CCD which corresponds to 26% of individuals with normal results on sequencing analysis. We therefore suggest that screening for intragenic deletions and duplications by qPCR or MLPA should be considered for patients with CCD phenotype in whom DNA sequencing does not reveal a causative RUNX2 mutation.

Differential MSH2 promoter methylation in blood cells of Neurofibromatosis type 1 (NF1) patients.

Neurofibromatosis type 1 (NF1) is caused by NF1 gene mutations. The phenotype is highly variable, with 'modifiers' being discussed as potential determinants. Mismatch repair deficiency was shown to cause NF1 mutations, but constitutional mutation of mismatch repair genes was identified only once in a NF1 patient. We aimed to analyze whether DNA methylation of mismatch repair gene promoters, known to lead to transcriptional silencing, is associated with increased tumor load in NF1 defined by the number of cutaneous neurofibromas. Leukocyte DNA of 79 controls and 79 NF1 patients was investigated for methylation of mismatch repair genes MLH1, MSH2, MSH6, and PMS2 by methylation-specific PCR and pyrosequencing. MLH1, MSH6, and PMS2 promoters were not methylated. By contrast, we found promoter methylation of MSH2 with a higher rate of methylation in NF1 patients compared with controls. Furthermore, when comparing NF1 patients with a low vs those with a high number of cutaneous neurofibromas, MSH2 promoter methylation was significantly different. In patients with a high tumor burden, methylation of two (out of six) CpGs was enhanced. This finding was not confounded by age. In conclusion, enhanced methylation involving transcription start points of mismatch repair genes, such as MSH2 in NF1, has not been described so far. Methylation-induced variability of MSH2 gene expression may lead to variable mismatch repair capacity. Our results may point toward a role of MSH2 as a modifier for NF1, although the amount of DNA methylation and subsequent gene expression in other cell types of NF1 patients needs to be elucidated.

A new autosomal recessive syndrome characterized by ocular hypertelorism, distinctive face, mental retardation, brachydactyly, and genital abnormalities.

We report on three individuals of Muslim Arab origin from a village located in Northern Israel affected by an apparent autosomal recessive syndrome characterized by distinctive facial phenotype of which the most prominent feature is ocular hypertelorism. The other clinical features of the syndrome include variable degree of mental retardation, genital abnormalities dominated by short penis, and skeletal abnormalities including chest deformity (combination of upper pectus carinatum with lower pectus excavatum), and short palms with broad short fingers. Affected individuals displayed distinctive facial features including upslanting palpebral fissures, thick eyebrows, long philtrum, wide mouth with thin upper lip and upturned corners of the mouth, widow's peak, broad nasal bridge, and simple ears with fleshy overfolded helices. This phenotype does not fully meet typical diagnostic features of any known condition.

Multiple giant cell lesions in patients with Noonan syndrome and cardio-facio-cutaneous syndrome.

Noonan syndrome (NS) and cardio-facio-cutaneous syndrome (CFCS) are related developmental disorders caused by mutations in genes encoding various components of the RAS-MAPK signaling cascade. NS is associated with mutations in the genes PTPN11, SOS1, RAF1, or KRAS, whereas CFCS can be caused by mutations in BRAF, MEK1, MEK2, or KRAS. The NS phenotype is rarely accompanied by multiple giant cell lesions (MGCL) of the jaw (Noonan-like/MGCL syndrome (NL/MGCLS)). PTPN11 mutations are the only genetic abnormalities reported so far in some patients with NL/MGCLS and in one individual with LEOPARD syndrome and MGCL. In a cohort of 75 NS patients previously tested negative for mutations in PTPN11 and KRAS, we detected SOS1 mutations in 11 individuals, four of whom had MGCL. To explore further the relevance of aberrant RAS-MAPK signaling in syndromic MGCL, we analyzed the established genes causing CFCS in three subjects with MGCL associated with a phenotype fitting CFCS. Mutations in BRAF or MEK1 were identified in these patients. All mutations detected in these seven patients with syndromic MGCL had previously been described in NS or CFCS without apparent MGCL. This study demonstrates that MGCL may occur in NS and CFCS with various underlying genetic alterations and no obvious genotype-phenotype correlation. This suggests that dysregulation of the RAS-MAPK pathway represents the common and basic molecular event predisposing to giant cell lesion formation in patients with NS and CFCS rather than specific mutation effects.

Robinow syndrome: phenotypic variability in a family with a novel intragenic ROR2 mutation.

Robinow syndrome comprises dysmorphic facial features, short stature, brachymesomelia, segmental spine defects, and genital hypoplasia. The range of severity in this disorder is broad. We report on the clinical and molecular findings of two sib pairs from the same extended family with Robinow syndrome due to a novel intragenic ROR2 deletion involving exons 6 and 7 that could not be detected by sequencing. The affected individuals exhibited variability with respect to the cleft lip, cleft palate, and cardiac findings and for the presence in one of the patients of syringomyelia, which has not been previously reported in Robinow syndrome.

Blepharophimosis-ptosis-epicanthus inversus syndrome in a girl with chromosome translocation t(2;3)(q33;q23).

We report on a young female patient with the clinical features of blepharophimosis-ptosis-epicanthus inversus syndrome (BPES, OMIM 110100) and a balanced chromosome translocation 46, XX, t(2;3)(q33;q23)dn.BPES is a rare autosomal dominant congenital disorder characterized by the eponymous oculo-facial features that are, in female patients, associated either with (type 1 BPES) or without (type 2 BPES) premature ovarian failure. Both types of BPES are caused by heterozygous mutations in the FOXL2 gene, which is located in chromosome band 3q23. Chromosome aberrations such as balanced rearrangements have only rarely been observed in BPES patients but can provide valuable information about regulatory regions of FOXL2. The translocation in this patient broadens our knowledge of pathogenic mechanisms in BPES and highlights the importance of conventional cytogenetic investigations in patients with negative results of FOXL2 mutation screening as a prerequisite for optimal management and genetic counseling.

Congenital central hypoventilation syndrome with hyperinsulinism in a preterm infant.

Congenital central hypoventilation syndrome (CCHS), a rare disorder typically presenting in the newborn period, results in over 90% of cases from PHOX2B polyalanine repeat mutations. It is characterized by alveolar hypoventilation, symptoms of autonomic nervous system dysregulation, and in a subset of cases Hirschsprung's disease and, later, tumors of neural crest origin. We describe a preterm infant with severe phenotype of CCHS and hyperinsulinism. A novel de novo heterozygote missence mutation (Gly68Cys) in the PHOX2B gene could be identified. Based on the observation of three patients presenting with the combination of congenital hyperinsulinism and CCHS, hyperinsulinism might represent an additional clinical feature of CCHS.

Missense mutations in the forkhead domain of FOXL2 lead to subcellular mislocalization, protein aggregation and impaired transactivation.

Mutations of the FOXL2 gene have been shown to cause blepharophimosis syndrome (BPES), characterized by an eyelid malformation associated with premature ovarian failure or not. Recently, polyalanine expansions and truncating FOXL2 mutations have been shown to lead to protein mislocalization, aggregation and altered transactivation. Here, we study the molecular consequences of 17 naturally occurring FOXL2 missense mutations. Most of them map to the conserved DNA-binding forkhead domain (FHD). The subcellular localization and aggregation pattern of the mutant FOXL2 proteins in COS-7 cells was variable and ranged from a diffuse nuclear distribution like the wild-type to extensive nuclear aggregation often in combination with cytoplasmic mislocalization and aggregation. We also studied the transactivation capacity of the mutants in FOXL2 expressing granulosa-like cells (KGN). Several mutants led to a loss-of-function, while others are suspected to induce a dominant negative effect. Interestingly, one mutant that is located outside the FHD (S217F), appeared to be hypermorphic and had no effect on intracellular protein distribution. This mutation gives rise to a mild BPES phenotype. In general, missense mutations located in the FHD lead to classical BPES and cannot be correlated with expression of the ovarian phenotype. However, a potential predictive value of localization and transactivation assays in the making of genotype-phenotype correlations is proposed. This is the first study to demonstrate that a significant number of missense mutations in the FHD of FOXL2 lead to mislocalization, protein aggregation and altered transactivation, and to provide insights into the pathogenesis associated with missense mutations of FOXL2 in human disease.

Hay-Wells syndrome in a child with mutation in the TP73L gene.

Hay-Wells syndrome is a rare form of ectodermal dysplasia, also known as AEC syndrome (Ankyloblepharon filiforme adnatum, Ectodermal effects, Cleft lip/palate). It is inherited in an autosomal dominant fashion with variable expression, featuring congenital abnormalities of skin, hair, teeth, nail, eccrine and mucous glands. We present a three-month-old boy, born to unaffected parents, with typical clinical findings of AEC syndrome. In this boy, a mutation Ile537Thr (c.1610C>T) in the sterile alpha motive (SAM) domain of the TP73L (p63) gene was detected. Because of the broad spectrum of related syndromes such as Rapp-Hodgkin syndrome, Bowen-Armstrong syndrome, CHAND syndrome and epidermolysis bullosa hereditaria, the diagnosis of AEC should be base don both clinical findings and genetic analysis.

Comparative proteomics in neurodegenerative and non-neurodegenerative diseases suggest nodal point proteins in regulatory networking.

Neurodegenerative disorders (ND) encompass clinically and genetically heterogeneous diseases with considerable overlap of their clinical, neuropathological and molecular phenotype. Various causes of neurodegeneration in disease may affect eventually the same proteins within protein networks. To identify common changes in ND, we compared brain protein changes detected by 2-D electrophoresis in four mouse models for ND: (i) Parkinson's disease, (ii) Huntington's disease, (iii) prion disease Scrapie, and (iv) a model for impaired synaptic transmission. To determine specificity of these changes for ND, we extended the scope of our investigation to three neurological conditions that do not result in neurodegeneration (non-ND). We detected 12 to 216 consistent qualitative or quantitative protein changes in individual ND and non-ND models when compared to controls. Up to 36% of these proteins were found to be altered in multiple disease states (at least three) and were therefore termed nodal point proteins. Alterations in alpha B-Crystallin and splicing factor 3b (subunit 4) occurred in at least three ND but not in non-ND. In contrast, alterations in peroxiredoxin 1 and 3, astrocytic phosphoprotein PEA15, complexin 2 and aminoacylase 1 were common to both ND and non-ND. Finally, we investigated the expression pattern of the nodal point proteins in three inbred mouse strains and found different protein abundance (expression polymorphisms) in all cases. Nodal point proteins showing expression polymorphisms may be candidate proteins for disease associated modifiers.

Mutation analysis of BRCA1 and BRCA2 genes in Iranian high risk breast cancer families.

PURPOSE: Germline mutations in either BRCA1 or BRCA2 genes are responsible for the majority of hereditary breast and ovarian cancers. At present, over thousand distinct BRCA1 and BRCA2 mutations have been identified. Specific mutations are found to be common within particular populations, resulting from genetic founder effects. To investigate the contribution of germline mutations in these two genes to inherited breast cancer in Iran, we performed BRCA1/BRCA2 mutation analyses in ten Iranian high risk breast cancer families. This is the first study analysing the complete coding sequences of both genes that concerns the Iranian population. METHODS: BRCA1/BRCA2 mutation detection included sequencing of the coding and the 3' and 5' untranslated regions. To detect large genomic rearrangements in the BRCA1 gene semi-quantitative multiplex PCR was performed. RESULTS: Two pathogenic mutations in the BRCA2 gene were detected: a novel deletion c.4415_4418delAGAA and a previously described insertion c.6033_6034insGT. In addition, one intronic variation g.5075-53C > T and a deletion/insertion g.*381_389del9ins29 in the 3' untranslated region of BRCA1 were found in two of the investigated families. Both sequence alterations were absent in an age matched Iranian control group. The BRCA2 homozygous variation p.N372H, previously associated with an increased risk for developing breast cancer, was not identified in this study. We did not detect large genomic rearrangements in BRCA1 in patients tested negatively for disease causing mutations in both genes by standard sequencing. CONCLUSIONS: At present, the BRCA2 mutations c.4415_4418delAGAA and c.6033_6034insGT have not been identified in any investigated population except the Iranian. Whether both mutations are specific for the Iranian population or a special subgroup remains to be investigated in larger studies. The absence of BRCA1 mutations in the analysed families may suggest that penetrance or prevalence of BRCA1 mutations may be lower in Iran.

Cherubism - new hypotheses on pathogenesis and therapeutic consequences.

AIMS: The hereditary occurrence of cherubism indicates a probable genetic aetiology: a correlation with a mutation in the gene SH3BP2 has been demonstrated. A convincing concept of formal pathogenesis is not yet available. The study was aimed at advancing the understanding of the pathogenesis of cherubism by presenting a case study including genetic findings and an evaluation of the literature. RESULTS AND CONCLUSION: Because of its association with the development of the second and third molars, cherubism could be defined as a genetically determined alteration of tooth development. In this context, disturbed PTHrP - PTHrP receptor interaction induced by the mutation in SH3BP2 is discussed. The temporal and spatial determination of the clinical symptoms is explained by an interaction of SH3BP2-dependent signal transduction pathways with jaw morphogenesis (e.g. Hox-gene Msx-1). Because of the disease-induced lack of determination of the cap phase of the second and third molar, a spatial compartmentation, which is necessary for normal dental development, does not take place. This leads to dysregulation of mesenchymal bone building tissue areas, and to the development of giant cell granulomas with high osteoclastic activity. Because of the genetic determination of cherubism and the associated dedifferentiation of the diseased tissue, a surgical removal should be exclusively restricted to specific indications. Therefore an attitude of wait and see is preferred.

Endocrinological and genetic studies in patients with Polycystic Ovary Syndrome (PCOS).

Our studies involved 21 women of Caucasian descent with PCOS, as diagnosed by ultrasound, clinical and hormonal findings. We determined 17alpha-OHP, 21-DOF and cortisol levels both just before and one hour after intravenous ACTH administration (0.25 mg Synacthen) in addition to the basal plasma levels of DHEA-S and free testosterone. We screened the CYP21 gene for 12 common-point mutations, finding five heterozygous mutations in 4 out of 21 cases (19%): a splice-site mutation in intron 2 in three cases, and a I172N mutation in exon 4 in two cases. These patients also displayed significantly higher 21-DOF or 17alpha-OHP plasma levels after ACTH administration, suggesting a partial 21-hydroxylase deficiency. Furthermore, we found the basal plasma DHEA-S levels or DHEA-S/F ratios in 11 of 21 patients (52%) to be higher than the means + 2SD of control females, indicating partial 3beta-HSD deficiency or 17,20-LHA. According to the literature, mutations could not be found in the genes of PCO cases with hormonal activity changes in the last two enzymes. The DDT metabolite o,p'-DDD is a strong inhibitor of 3beta-HSD, and DDT can induce 17,20-LHA, implying a possible connection between cases of PCOS women born in East Germany after 1955 and their prenatal DDT uptake. The approximately fourfold higher prevalence of PCO and significantly increased frequency of 3beta-HSD-deficiency and 17,20-LHA found in women with PCOS born since 1955-the time of massive application of DDT-give weight to the thesis that DDT, rather than genetic factors, has played a part in this upsurge.