Search results for " Mutation"

Detection of a novel Cys628STOP mutation of the myosin VIIA gene in Usher syndrome type Ib.

1998

A Spanish family with three Usher I syndrome-affected members was linked to markers located on chromosome 11q. A search for mutations on the myosin VIIA gene revealed a novel mutation (Cys628STOP) on exon 16 segregating with the disorder in a homozygous state. This nonsense mutation could be responsible for the disease since it leads to a truncated protein that presumably has no function.

Novel missense mutation in the ATP1A2 gene associated with atypical sporapedic hemiplegic migraine

2019

Hemiplegic migraine (HM) is a rare subtype of migraine with aura in which attacks include transient motor weakness or hemiparesis that can last several days. HM is linked to mutations in three different genes, CACNA1A, ATP1A2 and SCN1A, which encode for ion transporters. The clinical spectrum includes atypical symptoms such as impaired consciousness, epileptic seizures, permanent cerebellar ataxia or mental retardation. We describe a novel mutation found in the ATP1A2 gene in a patient with late-onset HM. His attacks were characterised by motor weakness associated with altered mental status, diplopia and ataxia. He also showed up MRI abnormalities and incomplete response to prophylactic the…

De-novo Williams–Beuren and inherited Marfan syndromes in a patient with developmental delay and lens dislocation

2017

Loss‐of‐function variants in ARHGEF9 are associated with an X‐linked intellectual disability dominant disorder

2021

ARHGEF9 defects lead to an X-linked intellectual disability disorder related to inhibitory synaptic dysfunction. This condition is more frequent in males, with a few affected females reported. Up to now, sequence variants and gross deletions have been identified in males, while only chromosomal aberrations have been reported in affected females who showed a skewed pattern of X-chromosome inactivation (XCI), suggesting an X-linked recessive (XLR) disorder. We report three novel loss-of-function (LoF) variants in ARHGEF9: A de novo synonymous variant affecting splicing (NM_015185.2: c.1056G>A, p.(Lys352=)) in one female; a nonsense variant in another female (c.865C>T, p.(Arg289*)), that is, a…

AMPA receptor GluA2 subunit defects are a cause of neurodevelopmental disorders.

2019

AMPA receptors (AMPARs) are tetrameric ligand-gated channels made up of combinations of GluA1-4 subunits encoded by GRIA1-4 genes. GluA2 has an especially important role because, following post-transcriptional editing at the Q607 site, it renders heteromultimeric AMPARs Ca2+-impermeable, with a linear relationship between current and trans-membrane voltage. Here, we report heterozygous de novo GRIA2 mutations in 28 unrelated patients with intellectual disability (ID) and neurodevelopmental abnormalities including autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). In functional expression studies, mutations lead to a dec…

Prevalence of acquired resistance mutations in a large cohort of perinatally infected HIV-1 patients

2019

Association between the HFE mutations and longevity: a study in Sardinian population

2003

Hereditary hemochromatosis is an HLA-linked inherited disease characterised by inappropriately high absorption of iron by the gastrointestinal mucosa. The cysteine-to-tyrosine substitution at codon 282 of the HFE encoding gene sequence is responsible for the disease, although other variants, as H63D and S65C, may modify the affinity of the protein for transferrin receptors. We have recently reported that C282Y mutation is significantly increased in very old (>90 years) Sicilian women, suggesting a role in attainment of longevity. In addition, an increase of H63D polymorphism was also observed in these women but the difference was not significant. To validate and extend these results we inve…

The gene encoding ganglioside-induced differentiation-associated protein 1 is mutated in axonal Charcot-Marie-Tooth type 4A disease

2001

We identified three distinct mutations and six mutant alleles in GDAP1 in three families with axonal Charcot-Marie-Tooth (CMT) neuropathy and vocal cord paresis, which were previously linked to the CMT4A locus on chromosome 8q21.1. These results establish the molecular etiology of CMT4A (MIM 214400) and suggest that it may be associated with both axonal and demyelinating phenotypes.

A novel mutation of the DHCR7 gene in a sicilian compound heterozygote with Smith-Lemli-Opitz Syndrome

2005

Introduction: Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol biosynthesis, resulting from deficient 7-dehydrocholesterol reductase (3β-hydroxysterol Δ7-reductase) activity, the enzyme responsible for conversion of 7-dehydrocholesterol to cholesterol. SLOS is most common among people of European descent, with a reported incidence of 1 per 20 000–60 000 newborns, depending on the diagnostic criteria and the reference population. More than 80 different mutations have been identified in several hundred patients. In Italy, SLOS appears to be a rare condition, probably because of underdiagnosis. Method: We analyzed by direct sequencing the 7-dehydrocholesterol…

Contribution of Large Genomic Rearrangements in Italian Lynch Syndrome Patients: Characterization of a Novel Alu-Mediated Deletion

2012

Lynch syndrome is associated with germ-line mutations in the DNA mismatch repair (MMR) genes, mainlyMLH1andMSH2. Most of the mutations reported in these genes to date are point mutations, small deletions, and insertions. Large genomic rearrangements in the MMR genes predisposing to Lynch syndrome also occur, but the frequency varies depending on the population studied on average from 5 to 20%. The aim of this study was to examine the contribution of large rearrangements in theMLH1andMSH2genes in a well-characterised series of 63 unrelated Southern Italian Lynch syndrome patients who were negative for pathogenic point mutations in theMLH1,MSH2, andMSH6genes. We identified a large novel delet…