Sphingomyelin phosphodiesterase-1 (SMPD1) coding variants do not contribute to low levels of high-density lipoprotein cholesterol.
BACKGROUND
Niemann-Pick disease type A and B is caused by a deficiency of acid sphingomyelinase due to mutations in the sphingomyelin phosphodiesterase-1 (SMPD1) gene. In Niemann-Pick patients, SMPD1 gene defects are reported to be associated with a severe reduction in plasma high-density lipoprotein (HDL) cholesterol.


METHODS
Two common coding polymorphisms in the SMPD1 gene, the G1522A (G508R) and a hexanucleotide repeat sequence within the signal peptide region, were investigated in 118 unrelated subjects of French Canadian descent with low plasma levels of HDL-cholesterol (< 5th percentile for age and gender-matched subjects). Control subjects (n = 230) had an HDL-cholesterol level > the 25th percentile.


RESULTS
For G1522A the frequency of the G and A alleles were 75.2% and 24.8% respectively in controls, compared to 78.6% and 21.4% in subjects with low HDL-cholesterol (p = 0.317). The frequency of 6 and 7 hexanucleotide repeats was 46.2% and 46.6% respectively in controls, compared to 45.6% and 49.1% in subjects with low HDL-cholesterol (p = 0.619). Ten different haplotypes were observed in cases and controls. Overall haplotype frequencies in cases and controls were not significantly different.


CONCLUSIONS
These results suggest that the two common coding variants at the SMPD1 gene locus are not associated with low HDL-cholesterol levels in the French Canadian population.
Dastani
Zari
Z
Cardiovascular Research Laboratories, Division of Cardiology, McGill University Health Centre/Royal Victoria Hospital, Montréal, Québec H3A 1A1, Canada. zari.dastani@mail.mcgill.ca
Ruel
Isabelle L
IL
Engert
James C
JC
Genest
Jacques
J
Marcil
Michel
M
D002170:Canada / Q000453:epidemiology / Q000208:ethnology; D008076:Cholesterol, HDL / Q000097:blood*; D005602:France; D005787:Gene Frequency; D006801:Humans; D011110:Polymorphism, Genetic; D021382:Protein Sorting Signals; D012091:Repetitive Sequences, Nucleic Acid; D013108:Sphingomyelin Phosphodiesterase / Q000235:genetics*; D044465:White People
D008076:Cholesterol, HDL; D021382:Protein Sorting Signals; D013108:Sphingomyelin Phosphodiesterase