A novel mutation associated with congenital hyperinsulinism

Congenital hyperinsulinism is an important cause of persistent hypoglycemia in neonates. We present a term large-for-gestation neonate with congenital hyperinsulinism, who was found to have a novel sporadic missense mutation in the ABCC8 gene. The clinical phenotype of our case is described along with results of genetic testing. Our patient had an early onset of persistent hypoglycemia, which responded to diazoxide and octreotide. The echocardiogram revealed diffuse hypertrophy of the ventricular walls and septum, which regressed spontaneously by 8 months of age. The specific ABCC8 missense mutation has not been previously reported in association with congenital hyperinsulinism. Our case highlights the need for genetic evaluation in this condition. The unraveling of new mutations with unique phenotypic features may have diagnostic and prognostic utility.     

Warburg Micro syndrome in a Turkish boy

We report a 4-year-old Turkish boy with Warburg Micro syndrome born to consanguineous parents. He had ptosis, deep-set eyes, microphthalmia, microcornea, microcephaly, prominent ears and nasal root, micrognathia, hypertrichosis, spastic diplegia, skin hyperextensibility and joint hypermobility, hypogenitalism, cerebral atrophy and hypoplasia of corpus callosum and cerebellum. Sequence analysis of exon 8 of the RAB3GAP gene has confirmed the presence of a splice donor mutation (748+1G>A) in the homozygous state. Skin hyperextensibility and joint hypermobility in the affected child have not been reported in Warburg Micro syndrome cases to date.This report compares the symptoms and features of the case with previously reported cases of Warburg Micro syndrome.     

A De Novo novel mutation of the EDNRB gene in a Taiwanese boy with Hirschsprung disease.

Hirschsprung disease (HSCR) is a congenital disorder characterized by an absence of ganglion cells in the nerve plexuses of the lower digestive tract. Although mutations in eight different genes (EDNRB, EDN3, ECE1, SOX10, RET, GDNF, NTN, SIP1) have been identified in affected individuals, it is now clear that RET and EDNRB are the primary genes implicated in the etiology of HSCR. All eight genes are involved in the early development of the enteric nervous system, and most act through two distinct biochemical pathways mediated by RET and EDNRB. Mutations in RET and EDNRB account for up to 50% and 5% of HSCR cases in the general population, respectively. Interaction between these two signaling pathways could modify RET expression and, therefore, HSCR phenotype. Here, we report the case of a 1-year-old Taiwanese boy who presented with abdominal distension since birth and bilious vomiting after feeding. HSCR (short-segment type) was diagnosed based on X-ray, lower gastrointestinal series and biopsy findings. Mutation analysis revealed a heterozygous T>C missense mutation in exon 1 of the EDNRB gene, that substitutes the highly conserved cysteine-90 residue in the extracellular domain of the G protein-coupled receptor with an arginine residue (C90R). No RET gene mutation was detected in this patient.     

Urinary neutrophil gelatinase-associated lipocalin is associated with preeclampsia in a cohort of Turkish women

Purpose: We investigated the optimal cut-off level for urinary neutrophil gelatinase-associated lipocalin (NGAL) in preeclamptic patients to confirm the diagnosis.

Methods: Urinary NGAL concentrations were measured by specific enzyme-linked immunosorbent assay (ELISA).

Results: Patients with preeclampsia had significantly higher urinary NGAL concentrations than controls (mean: 387 ng/ml vs. 188 ng/ml, respectively; P< 0.001). Using a cutoff value 252 ng/ml for urinary NGAL to confirm diagnosis of preeclampsia, sensitivity, and specificity were 92% and 91%, respectively.

Conclusion: Urinary NGAL concentrations were significantly elevated in women with preeclampsia versus normotensive controls.     

Prothrombin G20210A mutation is not associated with recurrent miscarriages

OBJECTIVE: To assess the association between prothrombin G20210A mutation and recurrent miscarriages. STUDY DESIGN: A literature review was performed in Medline identifying articles from 1966 to December 2000. Articles meeting inclusion criteria were systematically reviewed and included in a meta-analysis. RESULTS: Six trials, all case-controlled, were identified. These trials included 323 women with recurrent pregnancy loss. The odds ratio (OR) for heterozygous prothrombin mutation was 1.9 (95% confidence interval (CI) 0.98-4.14), and for homozygous prothrombin mutation was 3.76 (95% CI 0.75-18.77). The OR for prothrombin mutation and primary recurrent abortion was 2.19 (95% CI 0.61-7.89) and for prothrombin mutation and secondary recurrent abortion was 1.29 (95% CI 0.2-8.36). CONCLUSION: There is no evidence to support an association of prothrombin G20210A mutation with recurrent miscarriages.     

A novel de novo mutation in COL2A1 gene associated with fetal skeletal dysplasia

ObjectiveSkeletal dysplasias, caused by genetic mutations, are a heterogenous group of heritable disorders affecting bone development during fetal life. Stickler syndrome, one of the skeletal dysplasias, is an autosomal dominant connective tissue disorder caused by abnormal collagen synthesis owing to a genetic mutation in COL2A1.Case reportWe present the case of a 38-year-old multipara woman whose first trimester screening showed a normal karyotype. However, the bilateral femur and humerus length symmetrically shortened after 20 weeks. Next-generation sequencing for mutations in potential genes leading to skeletal dysplasia detected a novel de novo mutation (c.1438G > A, p.Gly480Arg) in COL2A1, causing Stickler syndrome type 1. This pathogenic mutation might impair or destabilize the collagen structure, leading to collagen type II, IX, and XI dysfunction.ConclusionWe identified a novel de novo mutation in COL2A1 related to the STL1 syndrome and delineated the extent of the skeletal dysplasia disease spectrum.     

Deleterious mutation in SYCE1 is associated with non-obstructive azoospermia

Purpose

To determine the molecular basis of familial, autosomal-recessive, non-obstructive azoospermia in a consanguineous Iranian Jewish family.

Methods

We investigated the genetic cause of non-obstructive azoospermia in two affected siblings from a consanguineous family. Homozygosity mapping in the DNA samples of the patients and their normospermic brother was followed by exome analysis of one of the patients. Other family members were genotyped for the mutation by Sanger sequencing. The mutation effect was demonstrated by immunostaining of the patients’ testicular tissue.

Results

The two patients were homozygous for a splice site mutation in SYCE1 which resulted in retention of intron three in the cDNA and premature stop codon. SYCE1 encodes a Synaptonemal Complex protein which plays an essential role during meiosis. Immunostaining of patient’s testicular tissue with anti-Syce1 antibody revealed an undetectable level of Syce1. Histological examination of the patients’ tissue disclosed immature-stages spermatocytes without mature forms, indicating maturation arrest.

Conclusion

The significance of most synaptonemal complex proteins was previously demonstrated in a mutant mouse model. The present report underscores the importance of synaptonemal complex proteins in spermatogenenesis in humans. Our new approach, combining homozygosity mapping and exome sequencing, resulted in one of the first reports of an autosomal-recessive form of NOA.     

A no-stop mutation in MAGEB4 is a possible cause of rare X-linked azoospermia and oligozoospermia in a consanguineous Turkish family

Purpose

The purpose of this study was to identify mutations that cause non-syndromic male infertility using whole exome sequencing of family cases.

Methods

We recruited a consanguineous Turkish family comprising nine siblings with male triplets; two of the triplets were infertile as well as one younger infertile brother. Whole exome sequencing (WES) performed on two azoospermic brothers identified a mutation in the melanoma antigen family B4 (MAGEB4) gene which was confirmed via Sanger sequencing and then screened for on control groups and unrelated infertile subjects. The effect of the mutation on messenger RNA (mRNA) and protein levels was tested after in vitro cell transfection. Structural features of MAGEB4 were predicted throughout the conserved MAGE domain.

Results

The novel single-base substitution (c.1041A>T) in the X-linked MAGEB4 gene was identified as a no-stop mutation. The mutation is predicted to add 24 amino acids to the C-terminus of MAGEB4. Our functional studies were unable to detect any effect either on mRNA stability, intracellular localization of the protein, or the ability to homodimerize/heterodimerize with other MAGE proteins. We thus hypothesize that these additional amino acids may affect the proper protein interactions with MAGEB4 partners.

Conclusion

The whole exome analysis of a consanguineous Turkish family revealed MAGEB4 as a possible new X-linked cause of inherited male infertility. This study provides the first clue to the physiological function of a MAGE protein.

     

A null mutation in HLA-G is not associated with preeclampsia or intrauterine growth retardation

Modulation of the expression of genes of the major histocompatibility complex (MHC) in tissues at the maternal-fetal interface almost certainly plays a role in successful development of the semi-allogeneic fetus. While expression of the classical class I genes (HLA-A, B, C) is low to non-existent at this site, the non-classical molecule, HLA-G, is expressed uniquely in fetal cells at the maternal-fetal interface. The recent demonstration that homozygotes for a deletion mutation in exon 3 (1597DeltaC) of HLA-G do not express the full-length HLA-G1 isoforms indicates a potential reduction in expression of this isoform in heterozygotes. If the full-length isoform of HLA-G (i.e. HLA-G1) contributes to proper invasion of maternal spiral arteries by extravillous cytotrophoblast, then 1597DeltaC heterozygotes could be at increased risk for disorders of trophoblast invasion. Two populations, infants with intrauterine growth retardation (IUGR) and infants of preeclamptic (PE) mothers, were genotyped for the 1597DeltaC polymorphism. The frequency of 1597DeltaC in these samples was not significantly different from healthy controls, suggesting that heterozygotes for this deletion mutation are not at significantly increased risk for PE or IUGR (P = 0.727 and 0.803, respectively).     

A compound heterozygous mutation of the SPINK5 gene in a Taiwanese boy with Netherton syndrome.

Netherton syndrome (NS) is a severe, autosomal, recessive ichthyosis. It is characterized by congenital ichthyosiform erythroderma (CIE), trichorrhexis invaginata (TI) - a distinctive hair-shaft anomaly, and atopic diathesis. Recently, pathogenic mutations were identified in serine protease inhibitor Kazal-type 5 (SPINK5), the gene that encodes lympho-epithelial Kazal-type-related inhibitor (LEKTI), a recently identified type of serine protease inhibitor involved in the regulation of skin barrier formation and immunity. Here we report the mutation analysis of a 7-year-old Taiwanese boy with NS manifesting CIE with pathognomic ichthyosis linearis circumflexa and TI. Direct DNA sequencing of SPINK5 demonstrated a compound heterozygous mutation in the proband, 2260A>T (K754X) in exon 24 and 2468delA in exon 26. The former is a novel mutation and was detected in the mother. The latter mutation was detected in the father and has been previously reported in several European families. Both mutations are expected to result in premature termination codons. Mutation analysis could provide a reliable prenatal diagnosis of this lethal ichthyosis.     

Melanocortin 3 receptor gene polymorphism is associated with polycystic ovary syndrome in Turkish population

Polycystic ovary syndrome (PCOS) is a frequent complex disorder with an ill-defined etiology. Genetic factors seem rather effective at the occurrence of the disease, however, the evidence of established various studies results are unsatisfied. We aimed to make a contribution to the genetic baseline of the disease by investigating melanocortin 3 receptor gene polymorphism in affected patients. 101 PCOS patients and 162 age-matched healthy volunteered control subjects recruited to the study. PCOS patients classified according to their BMI class and insulin resistance situation. Anthropometric measurements, physical examination results, laboratory findings, and hormone levels were recorded for each participant and analysis of two SNPs on the MC3R gene; rs3746619 and rs3827103 were performed. Although no significant difference was observed in rs3827103 polymorphism between PCOS patients and controls; rs3746619 polymorphism was determined associated with PCOS in the heritage of dominant (AA + AC) and co-dominant (AA) genotypes. Two polymorphisms did not found related to obesity and insulin resistance in PCOS subgroups analysis. MC3R gene rs 3746619 polymorphism was found associated with PCOS in the Turkish population and may make a contribution to the genetic baseline of the disease.     

Homozygous mutation of CRLF-1 gene in a Turkish newborn with Crisponi syndrome

Crisponi syndrome is a recently described rare autosomal recessive disorder. The main clinical features of the syndrome are neonatal onset of episodic contractions of the facial muscles with trismus and abundant salivation resembling a tetanic spasm. Herein, we report a case of 3-day-old male neonate presenting with trismus, abundant salivation, feeding difficulties, camptodactyly, and hyperthermia, which are consistent with the diagnostic criteria of Crisponi syndrome. The parents of the patient were consanguineous, supporting autosomal recessive inheritance. Molecular analysis revealed a homozygous mutation in cytokine receptor-like factor-1 gene in the patient.     

A familial Xp+ chromosome detected during fetal karyotyping,which is associated with short stature in four generations of a Turkish family

The short-stature homeobox-containing gene (SHOX) on chromosome Xp22.3 was recently identified as an important determinant of the stature phenotype. Deletions of the SHOX gene, some of them due to structural chromosome abnormalities, have been described in patients with idiopathic short stature and Leri-Weill syndrome. Additionally, haploinsufficiency of SHOX is a main cause for short stature seen in patients with Turner syndrome.Here we report an unusual X-chromosome abnormality, which was detected during a fetal karyotyping performed because of a previous child with Down syndrome. GTG banding demonstrated an extra chromosome segment on the terminal part of the short arm of chromosome X in the index case (karyotype: 46,X,Xp+). The same chromosomal abnormality was found in the mother and the maternal grandmother. All carriers of this chromosomal abnormality presented with short stature but no other associated symptoms.Whole chromosome painting of X revealed a homogeneous painting of the abnormal X chromosome indicating that no other chromosome was involved. Additional FISH studies with probe DXS1140 (Kallmann probe at Xp22.3), Quint-Essential X-Specific DNA (DMD probe at Xp21.2), XIST (at Xq13.2), and Tel Xq/Yq were performed, and no abnormality was observed in the intensities or the localizations of the probes signals. However, applying a specific SHOX gene probe (derived from cosmid LLNONO3M34F5) showed a loss of signal on the derivative X chromosome. Our results show that the Xp+ generation led to a deletion of the complete SHOX gene and caused short stature in the presented family.     

Ovarian cancer p53 mutation is associated with tumor microvessel density

OBJECTIVE: The objective of this study was to investigate the relationship between microvessel density, as measured by CD31 staining, and histopathologic factors as well as p53 tumor suppressor gene mutation in ovarian cancer. METHODS: Ovarian cancers (n = 77) were analyzed for p53 gene mutations and CD31 immunohistochemical expression. Histopathologic and mutational data were related to CD31 staining utilizing the Mantel correlation statistic. The microvessel density was scored by averaging counts from three high-power (200x) fields. Survival was based upon maximizing the hazard ratio. RESULTS: The mean microvessel density counts based on CD31 staining (vessels/HPF) for each FIGO stage and mutation type are as follows: Stage I (10.2), Stage II (10.7), Stage III (13.8), Stage IV (22.0), wild-type p53 (9.3), missense p53 mutation (14.4), and null p53 mutation (23.1). There was a significant correlation between microvessel density count and FIGO stage (P = 0.026), grade (P = 0.04), and p53 mutation type (P = 0.02). Median survival was more than doubled (6.4 vs 2.9 years; P = 0.009) for tumors with microvessel density counts less than or equal to 14 vessels/HPF. CONCLUSIONS: These data are consistent with the hypothesis that ovarian cancer p53 mutation functions to directly influence angiogenesis, which in turn compromises disease-specific survival. It also suggests validity to targeting p53 alterations with gene replacement as well as the use of antiangiogenesis agents as novel molecular-based therapeutics for ovarian cancer.