Dataset Information

Characterization of common SMPD1 mutations causing types A and B Niemann-Pick disease and generation of mutation-specific mouse models.

ABSTRACT: Herein we describe detailed characterization of four common mutations (L302P, H421Y, R496L and DeltaR608) within the acid sphingomyelinase (ASM) gene causing types A and B Niemann-Pick disease (NPD). In vitro and in situ enzyme assays revealed marked deficiencies of ASM activity in NPD cell lines homoallelic for each mutation, although Western blotting and fluorescent microscopy showed that the mutant ASM polypeptides were expressed at normal levels and trafficked to lysosomes. Co-immunoprecipitation of the polypeptides with the ER chaperone, BiP, confirmed these findings, as did in vitro expression of the mutant cDNAs in reticulocyte lysates. We further developed a computer assisted, three-dimensional model of human ASM based on homologies to known proteins, and used this model to map each NPD mutation in relation to putative substrate binding, hydrolysis and zinc-binding domains. Lastly, we generated transgenic mice expressing the R496L and DeltaR608 mutations on the complete ASM knock-out background (ASMKO), and established breeding colonies for the future evaluation of enzyme enhancement therapies. Analysis of these mice demonstrated that the mutant ASM transgenes were expressed at high levels in the brain, and in the case of the DeltaR608 mutation, produced residual ASM activity that was significantly above the ASMKO background.

SUBMITTER: Jones I

PROVIDER: S-EPMC2621017 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Characterization of common SMPD1 mutations causing types A and B Niemann-Pick disease and generation of mutation-specific mouse models.

Jones Iwan I He Xingxuan X Katouzian Fourogh F Darroch Peter I PI Schuchman Edward H EH

Molecular genetics and metabolism 20080923 3

Herein we describe detailed characterization of four common mutations (L302P, H421Y, R496L and DeltaR608) within the acid sphingomyelinase (ASM) gene causing types A and B Niemann-Pick disease (NPD). In vitro and in situ enzyme assays revealed marked deficiencies of ASM activity in NPD cell lines homoallelic for each mutation, although Western blotting and fluorescent microscopy showed that the mutant ASM polypeptides were expressed at normal levels and trafficked to lysosomes. Co-immunoprecipit ...[more]

PMID: 18815062

Similar Datasets

Project description:BackgroundClinical observations and molecular analysis of the SMPD1 gene in Chinese patients with acid sphingomyelinase deficiency Niemann-Pick disease (NPD) are scarce.MethodsA cohort of 27 Chinese patients diagnosed with acid sphingomyelinase deficiency, within the past five years, were collected and investigated for genotype, phenotype, and their correlations.ResultsThe majority of our patients (25/27) were under 18 years of age. From the cohort group, eight (30%) fulfilled characters of type A. Four other patients experienced neurologic involvement after two years of age, these were classified as intermediate type. The remaining fifteen presented without clear neurologic involvement and were regarded as type B. One patient, from the type B group, presented with the unusual symptom of a secondary amenorrhea. Three patients, one from the type B group and two from the intermediate group, presented with pronounced proteinuria, in the late stages of the disease, indicating possible kidney involvement in NPD. Twenty-four SMPD1 gene mutations had been identified; eighteen of these are novel ones. These included four exonic small deletions/duplications (c.4delC, c.147_150del4, c.842-849dup8, c.1307-1312dup6), one termination mutation (p.Glu248X), and thirteen exonic point mutations (p.Gly336Ser, p.Trp342Cys, p.Leu382Phe, p.Pro429Leu, p.Pro430Ser, p.Trp437Arg, p.Thr451Pro, p.His461Pro, p.Ala484Val, p.Ser486Arg, p.Tyr500His, p.Pro533Leu, p.Val559Leu). Notably, eight mutations had more than one occurrence with c.4delC and p.Glu248X accounting for ~30% of all alleles. Correlation analysis of genotype and phenotype indicated eight mutations, c.842-849dup8, p.Glu248X, p.Arg230Cys, p.Trp437Arg, p.His461Pro, p.Ala484Val p.Ser486Arg, and p.Pro533Leu,to be severe mutations. Five mutations, c.4delC, p.Leu382Phe, p.Pro429Leu, p.Pro430Ser and p.Val559Leu were projected to be mild mutations. Interestingly, three intermediate individuals carried combinations of a mild mutation, c.4delC, on one allele and a severe mutation on the other allele.ConclusionsThe Chinese population may have a comparably high incidence of sphingomyelinase-deficient Niemann-Pick disease type A. This study has identified some novel genotype and phenotype correlations in this rare and devastating disorder.

Dataset Information

Characterization of common SMPD1 mutations causing types A and B Niemann-Pick disease and generation of mutation-specific mouse models.

Publications

Characterization of common SMPD1 mutations causing types A and B Niemann-Pick disease and generation of mutation-specific mouse models.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets