16p11.2 600 kb Duplications confer risk for typical and atypical Rolandic epilepsy

Rolandic epilepsy (RE) is the most common idiopathic focal childhood epilepsy. Its molecular basis is largely unknown and a complex genetic etiology is assumed in the majority of affected individuals. The present study tested whether six large recurrent copy number variants at 1q21, 15q11.2, 15q13.3, 16p11.2, 16p13.11 and 22q11.2 previously associated with neurodevelopmental disorders also increase risk of RE. Our association analyses revealed a significant excess of the 600 kb genomic duplication at the 16p11.2 locus (chr16: 29.5-30.1 Mb) in 393 unrelated patients with typical (n = 339) and atypical (ARE; n = 54) RE compared with the prevalence in 65 046 European population controls (5/393 cases versus 32/65 046 controls; Fisher's exact test P = 2.83 × 10−6, odds ratio = 26.2, 95% confidence interval: 7.9-68.2). In contrast, the 16p11.2 duplication was not detected in 1738 European epilepsy patients with either temporal lobe epilepsy (n = 330) and genetic generalized epilepsies (n = 1408), suggesting a selective enrichment of the 16p11.2 duplication in idiopathic focal childhood epilepsies (Fisher's exact test P = 2.1 × 10−4). In a subsequent screen among children carrying the 16p11.2 600 kb rearrangement we identified three patients with RE-spectrum epilepsies in 117 duplication carriers (2.6%) but none in 202 carriers of the reciprocal deletion. Our results suggest that the 16p11.2 duplication represents a significant genetic risk factor for typical and atypical R

Next Generation Sequencing Approach in a Prenatal Case of Cardio-Facio-Cutaneus Syndrome

Cardiofaciocutaneous syndrome (CFCS) belongs to a group of developmental disorders due to defects in the Ras/Mitogen-Activated Protein Kinase (RAS/MAPK) signaling pathway named RASophaties. While postnatal presentation of these disorders is well known, the prenatal and neonatal characteristics are less recognized. Noonan syndrome, Costello syndrome, and CFCS diagnosis should be considered in pregnancies with a normal karyotype and in the case of ultrasound findings such as increased nuchal translucency, polyhydramnios, macrosomia and cardiac defect. Because all the RASopathies share similar clinical features, their molecular characterization is complex, time consuming and expensive. Here we report a case of CFCS prenatally diagnosed through Next Generation Prenatal Diagnosis (NGPD), a new targeted approach that allows us to concurrently investigate all the genes involved in the RASophaties

Lipoid congenital adrenal hyperplasia by steroidogenic acute regulatory protein (STAR) gene mutation in an Italian infant: an uncommon cause of adrenal insufficiency

Abstract Background Lipoid congenital adrenal hyperplasia (CAH) (OMIM n. 201710) is the most severe form of congenital adrenal hyperplasia. It is characterized by severe adrenal and gonadal steroidogenesis impairment due to a defect in the conversion of cholesterol to pregnenolone. Affected infants experience salt loss, but glucocorticoid and mineralocorticoid replacement therapy enables long-term survival. Classic lipoid congenital adrenal hyperplasia is relatively common in Japan and Korea but extremely rare in Caucasian populations. Case presentation A female infant of Italian origin came to our attention in late infancy with a clinical picture of acute adrenal insufficiency. The study of the STAR gene revealed two genomic variants c.562C > T and c.577C > T in compound heterozygosity. At the protein level, the two mutations determine the p.Arg188Cys variant (rs104894090) and the p.Arg193Ter variant (rs387907235), respectively. Sanger sequencing was used to confirm the identified variants and to perform familial study. The mother carried the p.Arg188Cys variant, while the father carried the p.Arg193Ter variant. Conclusion To our knowledge this is the second case of classic lipoid congenital adrenal hyperplasia reported in the Italian population. STAR mutations resulting in lipoid congenital adrenal hyperplasia should be considered all over the world in the differential diagnosis of newborn babies and infants with primary adrenal insufficiency

Alport syndrome and leiomyomatosis: the first deletion extending beyond COL4A6 intron 2.

Alport syndrome (ATS) is a nephropathy characterized by the association of progressive hematuric nephritis with ultrastructural changes of the glomerular basement membrane (thinning, thickening, and splitting), sensorineural deafness, and variable ocular abnormalities (anterior lenticonus, macular flecks, and cataracts). The most common mode of transmission is X-linked inheritance, due to COL4A5 mutations. X-linked ATS is rarely associated with diffuse leiomyomatosis (DL), a benign hypertrophy of the visceral smooth muscle in gastrointestinal, respiratory, and female reproductive tracts. The ATS-DL complex is due to deletions that encompass the 5' ends of the COL4A5 and COL4A6 genes and include the bidirectional promoter. In this paper, we described 3 ATS-DL cases, 2 familial and 1 sporadic bearing a deletion encompassing the 5'-end of both the COL4A5 and COL4A6 genes, as identified by multiplex ligation-dependent probe amplification (MLPA) analysis. The array-CGH technique allowed a better definition of deletion size, confirming that the proximal breakpoint was within COL4A6 intron 2 in 2 cases. Surprisingly, 1 case had a deletion extending proximally beyond exon 3 of COL4A6, as confirmed by qPCR analysis. This is the largest deletion reported to date that has been associated with ATS-DL and this case should lead us to reconsider the mechanisms that might be involved in the development of diffuse leiomyomatosis

Unusual presentation of Denys-Drash syndrome in a girl with undisclosed consumption of biotin

We describe a 46,XX girl with Denys-Drash syndrome (DDS), showing both kidney disease and genital abnormalities, in whom a misdiagnosis of hyperandrogenism was made. A 15 year-old girl was affected by neonatal nephrotic syndrome, progressing to end stage kidney failure. Hair loss and voice deepening were noted during puberty. Pelvic ultrasound and MRI showed utero-tubaric agenesis, vaginal atresia and urogenital sinus, with inguinal gonads. Gonadotrophin and estradiol levels were normal, but testosterone levels increased up to 285 ng/dL at Tanner stage 3. She underwent prophylactic gonadectomy and histopathology reported fibrotic ovarian cortex containing numerous follicles in different maturation stages and rudimental remnants of Fallopian tubes. No features of gonadoblastoma were detected. Unexpectedly, testosterone levels were found elevated 4 months after gonadectomy (157 ng/dL). Recent medical history revealed a chronic assumption of a high daily dose of biotin, as a therapeutic support for hair loss. Laboratory immunoassay instruments used streptavidin-biotin interaction to detect hormones and, in competitive immunoassays, high concentrations of biotin can result in false high results. Total testosterone, measured using liquid chromatography tandem mass spectrometry (LC-MS/MS), was found within reference intervals. Similar testosterone levels were detected repeating the immunoassay two weeks after biotin uptake interruption. Discordance between clinical presentation and biochemical results in patients taking biotin, should rise the suspicion of erroneous results. Improved communication among patients, health care providers, and laboratory professionals is required concerning the likelihood of biotin interference with immunoassays

Sulfonylurea-insensitive permanent neonatal diabetes caused by a severe gain-of-function Tyr330His substitution in Kir6.2

Background/aims: Mutations in KCNJ11, the gene encoding the Kir6.2 subunit of pancreatic and neuronal KATP channels, are associated with a spectrum of neonatal diabetes diseases. Methods: Variant screening was used to identify cause of neonatal diabetes, and continuous glucose monitoring used to assess effectiveness of sulfonylurea treatment. Electrophysiological analysis of variant KATP channel function was used to determine molecular basis. Results: We identified a previously uncharacterized KCNJ11 mutation, c.988T>C [pTyr330His], in an Italian child diagnosed with sulfonylurea-resistant permanent neonatal diabetes and developmental delay (iDEND). Functional analysis of recombinant KATP channels reveals that this mutation causes a drastic gain-of-function, due to a reduction in ATP-inhibition. Further, we demonstrate that the Tyr330His substitution causes a significant decrease in sensitivity to the sulfonylurea, glibenclamide. Conclusions: In this subject, the KCNJ11(c.988T>C) mutation provoked neonatal diabetes, with mild developmental delay, which was insensitive to correction by sulfonylurea therapy. This is explained by the molecular loss of sulfonylurea sensitivity conferred by the Tyr330His substitution, and highlights the need for molecular analysis of such mutations

Investigation of modifier genes within copy number variations in Rett syndrome.

MECP2 mutations are responsible for two different phenotypes in females, classical Rett syndrome and the milder Zappella variant (Z-RTT). We investigated whether copy number variants (CNVs) may modulate the phenotype by comparison of array-CGH data from two discordant pairs of sisters and four additional discordant pairs of unrelated girls matched by mutation type. We also searched for potential MeCP2 targets within CNVs by chromatin immunopreceipitation microarray (ChIP-chip) analysis. We did not identify one major common gene/region, suggesting that modifiers may be complex and variable between cases. However, we detected CNVs correlating with disease severity that contain candidate modifiers. CROCC (1p36.13) is a potential MeCP2 target, in which a duplication in a Z-RTT and a deletion in a classic patient were observed. CROCC encodes a structural component of ciliary motility that is required for correct brain development. CFHR1 and CFHR3, on 1q31.3, may be involved in the regulation of complement during synapse elimination, and were found to be deleted in a Z-RTT but duplicated in two classic patients. The duplication of 10q11.22, present in two Z-RTT patients, includes GPRIN2, a regulator of neurite outgrowth and PPYR1, involved in energy homeostasis. Functional analyses are necessary to confirm candidates and to define targets for future therapies