CLP1 Founder Mutation Links tRNA Splicing and Maturation to Cerebellar Development and Neurodegeneration

SummaryNeurodegenerative diseases can occur so early as to affect neurodevelopment. From a cohort of more than 2,000 consanguineous families with childhood neurological disease, we identified a founder mutation in four independent pedigrees in cleavage and polyadenylation factor I subunit 1 (CLP1). CLP1 is a multifunctional kinase implicated in tRNA, mRNA, and siRNA maturation. Kinase activity of the CLP1 mutant protein was defective, and the tRNA endonuclease complex (TSEN) was destabilized, resulting in impaired pre-tRNA cleavage. Germline clp1 null zebrafish showed cerebellar neurodegeneration that was rescued by wild-type, but not mutant, human CLP1 expression. Patient-derived induced neurons displayed both depletion of mature tRNAs and accumulation of unspliced pre-tRNAs. Transfection of partially processed tRNA fragments into patient cells exacerbated an oxidative stress-induced reduction in cell survival. Our data link tRNA maturation to neuronal development and neurodegeneration through defective CLP1 function in humans

Microcephaly, Dysmorphic Features, Corneal Dystrophy, Hairy Nipples, Underdeveloped Labioscrotal Folds, and Small Cerebellum in Four Patients

Pontocerebellar hypoplasia (PCH) can occur as an isolated entity or part of a syndrome. PCH has been reported with facial dysmorphism, ocular anomalies, and genital anomalies, but the co-occurrence of all four has not been previously described. We report on four patients, born to two consanguineous families that are not related to one another, with distinctive facial features (short forehead, laterally extended, medially flared eyebrows), corneal dystrophy, underdevelopment of labioscrotal folds, and nonprogressive PCH. In addition, the patients show hair extruding from the lactiferous ducts, which to our knowledge has not been described before. The parental consanguinity, affected siblings of both genders, and absent manifestations in parents, indicate an autosomal recessive pattern of inheritance as most likely. (C) 2016 Wiley Periodicals, Inc

A de novo complex chromosomal rearrangement involving chromosomes 2, 8 and 13 in a dysmorphic case with polysyndactyly

We report herein a case with dysmorphic features, polysyndactyly and psychomotor mental retardation, who had an apparently balanced de novo translocation between chromosomes 8 and 13 as well as a de novo insertion within chromosome 2 itself

Teratogenicity of Antiepileptic Drugs.

Objective: Antiepileptic drugs (AED) have chronic teratogenic effects, the most common of which are congenital heart disease, cleft lip/palate, urogenital and neural tube defects. The aim of our study is to examine teratogenic effects of AED and the correlation between these malformations and AED in single or multiple pregnancies

Homozygous mutation in NUP107 leads to microcephaly with steroid-resistant nephrotic condition similar to Galloway-Mowat syndrome

Background Microcephaly with nephrotic syndrome is a rare co-occurrence, constituting the Galloway-Mowat syndrome (GAMOS), caused by mutations in WDR73 (OMIM: 616144). However, not all patients harbour demonstrable WDR73 deleterious variants, suggesting that there are other yet unidentified factors contributing to GAMOS aetiology

Inactivating mutations in MFSD2A, required for omega-3 fatty acid transport in brain, cause a lethal microcephaly syndrome

10.1038/ng.3311NATURE GENETICS477809-813United State

Biallelic Mutations in TMTC3, Encoding a Transmembrane and TPR-Containing Protein, Lead to Cobblestone Lissencephaly

Cobblestone lissencephaly (COB) is a severe brain malformation in which overmigration of neurons and glial cells into the arachnoid space results in the formation of cortical dysplasia. COB occurs in a wide range of genetic disorders known as dystroglycanopathies, which are congenital muscular dystrophies associated with brain and eye anomalies and range from Walker-Warburg syndrome to Fukuyama congenital muscular dystrophy. Each of these conditions has been associated with alpha-dystroglycan defects or with mutations in genes encoding basement membrane components, which are known to interact with alpha-dystroglycan. Our screening of a cohort of 25 families with recessive forms of COB identified six families affected by biallelic mutations in TMTC3 (encoding transmembrane and tetratricopeptide repeat containing 3), a gene without obvious functional connections to alpha-dystroglycan. Most affected individuals showed brainstem and cerebellum hypoplasia, as well as ventriculomegaly. However, the minority of the affected individuals had eye defects or elevated muscle creatine phosphokinase, separating the TMTC3 COB phenotype from typical congenital muscular dystrophies. Our data suggest that loss of TMTC3 causes COB with minimal eye or muscle involvement

Mutations in CEP120 cause Joubert syndrome as well as complex ciliopathy phenotypes

Ciliopathies are an extensive group of autosomal recessive or X-linked disorders with considerable genetic and clinical overlap, which collectively share multiple organ involvement and may result in lethal or viable phenotypes. In large numbers of cases the genetic defect remains yet to be determined. The aim of this study is to describe the mutational frequency and phenotypic spectrum of the CEP120 gene.status: publishe