OBJECTIVE: To explore the genetic basis for a patient with early-onset retinitis pigmentosa (RP). METHODS: A patient who had presented at the West China Hospital of Sichuan University on March 10, 2020 was selected as the study subject. The patient and his parents were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing and in silico analysis. RESULTS: The patient has featured substantial loss of binocular vision field. Funduscopy revealed characteristic bone spicule-type pigment deposits, as well as attenuated retinal arterioles and pale-appearing optic discs. WES revealed that he has harbored compound missense variants of a RP-associated CRB1 gene, including c.2969T>C (p.Leu990Ser) and c.1816T>C (p.Cys606Arg), which were respectively inherited from his father and mother. Homozygous c.1816T>C (p.Cys606Arg) variant has been identified among RP patients, whilst the c.2969T>C (p.Leu990Ser) variant was unreported previously. Both variants were predicted as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). CONCLUSION The novel compound heterozygous variants of the CRB1 gene probably underlay the early-onset RP in this patient. Above finding has enriched the mutational spectrum of the CRB1 gene.
Male ; Female ; Humans ; China ; Genomics ; Homozygote ; Mothers ; Retinitis Pigmentosa/genetics* ; Eye Proteins/genetics* ; Membrane Proteins/genetics* ; Nerve Tissue Proteins/genetics*

Epilepsy ; genetics ; Humans ; Mutation ; NAV1.1 Voltage-Gated Sodium Channel ; Nerve Tissue Proteins ; genetics ; Sodium Channels ; genetics

Kallmann syndrome (KS) is a clinically and genetically heterogeneous disorder that occurs in either an inherited or a sporadic manner. KS results from failed embryonic migration of GnRH-1 neurons from the nasal placode to the hypothalamus, due to the abnormal development of olfactory nerves and bulbs. Hypogonadotropic hypogonadism is related to GnRH deficiency, and anosmia is associated with the absence or hypoplasia of olfactory bulbs and tracts. KS patients can also present some non-reproductive or non-olfactory anomalies in addition to the above typical symptoms. For the high complexity of the molecular genetic mechanism of KS, to date, only 6 KS-related genes have been identified. The KAL1 gene is responsible for the X chromosome-linked recessive form of KS, while the fibroblast growth factor receptor 1 (FGFR1/KAL2) and fibroblast growth factor 8 (FGF8/KAL6) genes are related to the autosomal dominant form of the disease. However, the mutations in these 6 genes account for only about 25 - 30% of all KS cases, which suggests that other pathogenic genes involved in KS remain to be discovered. This article presents an overview on the studies of the pathogenic genes, clinical diagnosis and treatment of KS.
Extracellular Matrix Proteins ; genetics ; Humans ; Kallmann Syndrome ; genetics ; Mutation ; Nerve Tissue Proteins ; genetics ; Receptor, Fibroblast Growth Factor, Type 1 ; genetics

Proline-rich transmembrane protein 2 (PRRT2) is the leading cause of paroxysmal kinesigenic dyskinesia (PKD), benign familial infantile epilepsy (BFIE), and infantile convulsions with choreoathetosis (ICCA). Reduced penetrance of PRRT2 has been observed in previous studies, whereas the exact penetrance has not been evaluated well. The objective of this study was to estimate the penetrance of PRRT2 and determine its influencing factors. We screened 222 PKD index patients and their available relatives, identified 39 families with pathogenic or likely pathogenic (P/LP) PRRT2 variants via Sanger sequencing, and obtained 184 PKD/BFIE/ICCA families with P/LP PRRT2 variants from the literature. Penetrance was estimated as the proportion of affected variant carriers. PRRT2 penetrance estimate was 77.6% (95% confidence interval (CI) 74.5%-80.7%) in relatives and 74.5% (95% CI 70.2%-78.8%) in obligate carriers. In addition, we first observed that penetrance was higher in truncated than in non-truncated variants (75.8% versus 50.0%, P = 0.01), higher in Asian than in Caucasian carriers (81.5% versus 68.5%, P = 0.004), and exhibited no difference in gender or parental transmission. Our results are meaningful for genetic counseling, implying that approximately three-quarters of PRRT2 variant carriers will develop PRRT2-related disorders, with patients from Asia or carrying truncated variants at a higher risk.
Dystonia ; Epilepsy, Benign Neonatal/genetics* ; Humans ; Membrane Proteins/genetics* ; Mutation ; Nerve Tissue Proteins/genetics* ; Pedigree ; Penetrance ; Seizures/genetics*

Schizophrenia (MIM 181500) is a complex disorder affecting approximately 1% of the population worldwide. Epidemiologic evidences, together with recent linkage and association studies, have clearly demonstrated the high heritability of schizophrenia (up to 80%). Uncovering the genetic mechanism of schizophrenia has became one of the greatest challenges for both psychiatry and genetics. In recent years, remarkable advances in the genetics of this disorder has been achieved with the rapid growth of human genome information and experiment technologies. Several candidate genes within some of the best-supported linkage regions have been reported and, more importantly, replicated. Moreover, these genes present a significant connection in the signaling pathways implicated in the development of schizophrenia, especially NMDA receptor-mediated glutamate transmission. In this review, we summarize the recent advances in the genetics of schizophrenia, focusing particularly on linkage disequilibrium analysis and the latest understanding of the neurobiology of the disorder.
Acyltransferases ; genetics ; Carrier Proteins ; genetics ; Dysbindin ; Dystrophin-Associated Proteins ; Humans ; Membrane Proteins ; genetics ; Nerve Tissue Proteins ; genetics ; Neuregulin-1 ; Receptors, N-Methyl-D-Aspartate ; genetics ; Schizophrenia ; genetics

Humans ; Esophageal Achalasia/genetics* ; Cardia ; Nerve Tissue Proteins ; Nuclear Pore Complex Proteins

Humans ; Hypertension ; genetics ; Multivariate Analysis ; Nerve Tissue Proteins ; genetics ; Polymorphism, Genetic

Ataxins ; Humans ; Male ; Middle Aged ; Nerve Tissue Proteins ; genetics ; Spinocerebellar Ataxias ; genetics ; Trinucleotide Repeats

Adult ; Humans ; Male ; Myoclonic Epilepsies, Progressive ; diagnostic imaging ; genetics ; therapy ; Nerve Tissue Proteins ; genetics ; Pedigree

OBJECTIVE: To explore the genetic basis for two Chinese pedigrees affected with Huntington disease and provide prenatal diagnosis for them. METHODS: Peripheral venous blood samples were collected from the probands. PCR and capillary gel electrophoresis were used to determine the number of CAG repeats in their IT15 gene. Pre-symptomatic testing was offered to their children and relatives, and prenatal diagnosis was provided to three pregnant women from the two pedigrees. RESULTS: The two probands, in addition with three asymptomatic members, were found to have a (CAG)n repeat number greater than 40. Upon prenatal diagnosis, the numbers of CAG repeats in two fetuses from pedigree 1 were determined as (16, 19) and (18, 19), both were within the normal range. A fetus from pedigree 2 was found to have a CAG repeat number of (15, 41), which exceeded the normal range. CONCLUSION Genetic testing can facilitate the diagnosis of Huntington disease and avoid further birth of affected children.
Child ; Female ; Genetic Testing ; Humans ; Huntington Disease/genetics* ; Nerve Tissue Proteins/genetics* ; Pedigree ; Pregnancy ; Prenatal Diagnosis