from #Audiology via ola Kala on Inoreader http://ift.tt/2As3gf7
via IFTTT
OtoRhinoLaryngology by Sfakianakis G.Alexandros Sfakianakis G.Alexandros,Anapafseos 5 Agios Nikolaos 72100 Crete Greece,tel : 00302841026182,00306932607174
Related Articles |
Kallmann Syndrome: Phenotype and Genotype of Hypogonadotropic Hypogonadism.
Metabolism. 2017 Nov 03;:
Authors: Stamou MI, Georgopoulos NA
Abstract
Isolated Gonadotropin-Releasing Hormone (GnRH) Deficiency (IGD) IGD is a genetically and clinically heterogeneous disorder. Mutations in many different genes are able to explain ~40% of the causes of IGD, with the rest of cases remaining genetically uncharacterized. While most mutations are inherited in X-linked, autosomal dominant, or autosomal recessive pattern, several IGD genes are shown to interact with each other in an oligogenic manner. In addition, while the genes involved in the pathogenesis of IGD act on either neurodevelopmental or neuroendocrine pathways, a subset of genes are involved in both pathways, acting as "overlap genes". Thus, some IGD genes play the role of the modifier genes or "second hits", providing an explanation for incomplete penetrance and variable expressivity associated with some IGD mutations. The clinical spectrum of IGD includes a variety of disorders including Kallmann Syndrome (KS), i.e. hypogonadotropic hypogonadism with anosmia, and its normosmic variation normosmic idiopathic hypogonadotropic hypogonadism (nIHH), which represent the most severe aspects of the disorder. Apart from these disorders, there are also "milder" and more common reproductive diseases associated with IGD, including hypothalamic amenorrhea (HA), constitutional delay of puberty (CDP) and adult-onset hypogonadotropic hypogonadism (AHH). Interestingly, neurodeveloplmental genes are associated with the KS form of IGD, due to the topographical link between the GnRH neurons and the olfactory placode. On the other hand, neuroendocrine genes are mostly linked to nIHH. However, a great deal of clinical and genetic overlap characterizes the spectrum of the IGD disorders. IGD is also characterized by a wide variety of non- reproductive features, including midline facial defects such as cleft lip and/ or palate, renal agenesis, short metacarpals and other bone abnormalities, hearing loss, synkinesia, eye movement abnormalities, poor balance due to cerebellar ataxia, etc. Therefore, genetic screening should be offered in patients with IGD, as it can provide valuable information for genetic counseling and further understanding of IGD.
PMID: 29108899 [PubMed - as supplied by publisher]
Related Articles |
Kallmann Syndrome: Phenotype and Genotype of Hypogonadotropic Hypogonadism.
Metabolism. 2017 Nov 03;:
Authors: Stamou MI, Georgopoulos NA
Abstract
Isolated Gonadotropin-Releasing Hormone (GnRH) Deficiency (IGD) IGD is a genetically and clinically heterogeneous disorder. Mutations in many different genes are able to explain ~40% of the causes of IGD, with the rest of cases remaining genetically uncharacterized. While most mutations are inherited in X-linked, autosomal dominant, or autosomal recessive pattern, several IGD genes are shown to interact with each other in an oligogenic manner. In addition, while the genes involved in the pathogenesis of IGD act on either neurodevelopmental or neuroendocrine pathways, a subset of genes are involved in both pathways, acting as "overlap genes". Thus, some IGD genes play the role of the modifier genes or "second hits", providing an explanation for incomplete penetrance and variable expressivity associated with some IGD mutations. The clinical spectrum of IGD includes a variety of disorders including Kallmann Syndrome (KS), i.e. hypogonadotropic hypogonadism with anosmia, and its normosmic variation normosmic idiopathic hypogonadotropic hypogonadism (nIHH), which represent the most severe aspects of the disorder. Apart from these disorders, there are also "milder" and more common reproductive diseases associated with IGD, including hypothalamic amenorrhea (HA), constitutional delay of puberty (CDP) and adult-onset hypogonadotropic hypogonadism (AHH). Interestingly, neurodeveloplmental genes are associated with the KS form of IGD, due to the topographical link between the GnRH neurons and the olfactory placode. On the other hand, neuroendocrine genes are mostly linked to nIHH. However, a great deal of clinical and genetic overlap characterizes the spectrum of the IGD disorders. IGD is also characterized by a wide variety of non- reproductive features, including midline facial defects such as cleft lip and/ or palate, renal agenesis, short metacarpals and other bone abnormalities, hearing loss, synkinesia, eye movement abnormalities, poor balance due to cerebellar ataxia, etc. Therefore, genetic screening should be offered in patients with IGD, as it can provide valuable information for genetic counseling and further understanding of IGD.
PMID: 29108899 [PubMed - as supplied by publisher]
Variants in CIB2 cause DFNB48 and not USH1J.
Clin Genet. 2017 Nov 07;:
Authors: Booth KT, Kahrizi K, Babanejad M, Daghagh H, Bademci G, Arzhangi S, Zareabdollahi D, Duman D, El-Amraoui A, Tekin M, Najmabadi H, Azaiez H, Smith RJ
Abstract
The genetic, mutational and phenotypic spectrum of deafness-causing genes shows great diversity and pleiotropy. The best examples are the group of genes, which when mutated can either cause non-syndromic hearing loss (NSHL) or the most common dual sensory impairment, Usher Syndrome (USH). Variants in the CIB2 gene have been previously reported to cause of hearing loss at the DFNB48 locus and deaf-blindness at the USH1J locus. In this study, we characterize the phenotypic spectrum in a multiethnic cohort with autosomal recessive non-syndromic hearing loss (ARNSHL) due to variants in the CIB2 gene. Of the 6 families we ascertained, 3 segregated novel loss-of-function variants, 2 families segregated missense variants (one novel) and 1 family segregated a previously reported pathogenic variant in trans with a frameshift variant. This report is the first to show that biallelic loss of function variants in CIB2 cause ARNSHL and not USH. In the era of precision medicine, providing the correct diagnosis (NSHL vs USH) is essential for patient care as it impacts potential intervention and prevention options for patients. Here we provide evidence disqualifying CIB2 as an USH-causing gene.
PMID: 29112224 [PubMed - as supplied by publisher]
![]() |
Related Articles |
An Application of NGS for Molecular Investigations in Perrault Syndrome: Study of 14 Families and Review of the Literature.
Hum Mutat. 2016 Dec;37(12):1354-1362
Authors: Lerat J, Jonard L, Loundon N, Christin-Maitre S, Lacombe D, Goizet C, Rouzier C, Van Maldergem L, Gherbi S, Garabedian EN, Bonnefont JP, Touraine P, Mosnier I, Munnich A, Denoyelle F, Marlin S
Abstract
Perrault syndrome (PS) is a rare autosomal recessive condition characterized by deafness and gonadic dysgenesis. Recently, mutations in five genes have been identified: C10orf2, CLPP, HARS2, HSD17B4, and LARS2. Probands included are presented with sensorineural deafness associated with gonadic dysgenesis. DNA was sequenced using next-generation sequencing (NGS) with a panel of 35 deafness genes including the five Perrault genes. Exonic variations known as pathogenic mutations or detected with <1% frequency in public databases were extracted and subjected to segregation analysis within each family. Both mutations and low coverage regions were analyzed by Sanger sequencing. Fourteen female index patients were included. The screening in four cases has been extended to four family members presenting with PS phenotype. For four unrelated patients (28.6%), causative mutations were identified: three homozygous mutations in C10orf2, CLPP, and HARS2, and one compound heterozygous mutation in LARS2. Three additional heterozygous mutations in LARS2 and HSD17B4 were found in three independent familial cases. All these missense mutations were verified by Sanger sequencing. Familial segregation analyses confirmed the molecular diagnosis in all cases carrying biallelic mutations. Because of NGS, molecular analysis confirmed the clinical diagnosis of PS in 28.6% of our cohort and four novel mutations were found in four Perrault genes. For the unsolved cases, exome sequencing should be performed to search for a sixth unknown PS gene.
PMID: 27650058 [PubMed - indexed for MEDLINE]