Kim SH, etal., Ann Clin Lab Sci. 2011 Fall;41(1):84-8.
Short-chain acyl-coenzyme A dehydrogenase deficiency (SCADD) is an autosomal recessive disorder of mitochondrial fatty acid oxidation associated with mutations in the ACADS gene (Acyl-CoA Dehydrogenase, Short-chain, OMIM #606885). SCADD is a heterogeneous condi
tion that has been associated with various clinical phenotypes ranging from fetal metabolic decompensation in infancy to asymptomatic individuals. Here, the first Korean neonate diagnosed with SCADD by biochemical and genetic findings is reported. The patient has remained asymptomatic by avoiding hypoglycemia. An increased concentration of butylcarnitine was detected on newborn screening. Subsequent urine organic acid analysis showed increased urinary excretion of ethylmalonic acid. To confirm the presence of the genetic abnormality, all the coding exons of the ACADS gene and flanking introns were amplified by the polymerase chain reaction (PCR). Sequence analysis of the ACADS gene revealed novel homozygous missence mutations, c. 1031A>G (p.E344G) in exon 9. In summary, the first Korean patient with confirmed SCADD by genetic analysis is reported with novel mutation.
Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is an inherited disorder of mitochondrial fatty acid oxidation associated with variations in the ACADS gene and variable clinical symptoms. In addition to rare ACADS inac
tivating variations, two common variations, c.511C > T (p.Arg171Trp) and c.625G > A (p.Gly209Ser), have been identified in patients, but these are also present in up to 14% of normal populations leading to questions of their clinical relevance. The common variant alleles encode proteins with nearly normal enzymatic activity at physiological conditions in vitro. SCAD enzyme function, however, is impaired at increased temperature and the tendency to misfold increases under conditions of cellular stress. The present study examines misfolding of variant SCAD proteins identified in patients with SCAD deficiency. Analysis of the ACADS gene in 114 patients revealed 29 variations, 26 missense, one start codon, and two stop codon variations. In vitro import studies of variant SCAD proteins in isolated mitochondria from SCAD deficient (SCAD-/-) mice demonstrated an increased tendency of the abnormal proteins to misfold and aggregate compared to the wild-type, a phenomenon that often leads to gain-of-function cellular phenotypes. However, no correlation was found between the clinical phenotype and the degree of SCAD dysfunction. We propose that SCAD deficiency should be considered as a disorder of protein folding that can lead to clinical disease in combination with other genetic and environmental factors.
OBJECTIVES: Genetically hypertensive rats provide an excellent model to investigate the genetic mechanisms of hypertension. We previously identified three differentially expressed genes, Acadsb (short/branched chain acyl-CoA dehydrogenase), Comt (catecholamine-O
-methyltransferase), and Pnpo (pyridoxine 5'-phosphate oxidase), in hypertensive and normotensive rat kidneys as potential susceptibility genes for rat hypertension. We examined the association of human homologues of these genes with human hypertension. METHODS: We sequenced three genes using samples from 48 or 96 hypertensive patients, identified single nucleotide polymorphisms, and genotyped them in a population-based sample of 1818 Japanese individuals (771 hypertensive individuals and 1047 controls). RESULTS: After adjustments for age, body mass index, present illness (hyperlipidaemia, diabetes mellitus), and lifestyle (smoking, alcohol consumption), multivariate logistic regression analysis revealed that -512A>G in ACADSB was associated with hypertension in women (AA vs AG + GG: odds ratio = 0.70, 95% confidence interval = 0.53-0.94). This single nucleotide polymorphism was in tight linkage disequilibrium with -254G>A. Furthermore, -1187G>C in COMT was associated with hypertension in men (GG vs CG + CC: odds ratio = 0.69, 95% confidence interval = 0.52-0.93) and was in tight linkage disequilibrium with 186C>T. After adjustments described above, -512 A>G and -254G>A in ACADSB were associated with variations in systolic blood pressure. ACADSB was in tight linkage disequilibrium with MGC35392 across a distance of 18.3 kb. COMT was not in linkage disequilibrium with any adjacent genes. Analysis indicated that two haplotypes of COMT were significantly associated with hypertension in men. CONCLUSION: Our study suggests the possible involvement of genetic polymorphisms in ACADSB and COMT in essential hypertension in the Japanese population.
