title: Mutations of the GLA gene in Korean patients with Fabry disease and frequency of the E66Q allele as a functional variant in Korean newborns.
abstract: Fabry disease is caused by an alpha-galactosidase A (GLA) deficiency. In this study, we identified 28 unrelated Korean families with Fabry disease with 25 distinct mutations in the GLA gene including six novel mutations (p.W47X, p.C90X, p.D61EfsX32, IVS4(-11)T>A, p.D322E and p.W349). Notably, five subjects from four unrelated families carried the p.E66Q variant, previously known as a pathogenic mutation in atypical Fabry disease. Among these patients, only one had proteinuria and two had hypertrophic cardiomyopathy without any other systemic manifestation of Fabry disease. Substantial residual GLA activity was shown both in the leukocytes of p.E66Q patients (19.0-30.3% of normal activity) and in transiently overexpressed COS-7 cells (43.8 + or - 3.03% of normal activity). Although GLA harboring p.E66Q is unstable at neutral pH, the enzyme is efficiently expressed in the lysosomes of COS-7 cells. The location of p.E66 is distant from both the active site and the dimer interface, and has a more accessible surface area than have other mutations of atypical Fabry disease. In addition, the allele frequency of p.E66Q determined in 833 unrelated Korean individuals was remarkably high at 1.046% (95% confidence interval, 0.458-1.634%). These results indicate that p.E66Q is a functional polymorphism rather than a pathogenic mutation.
authors.affiliation: Department of Pediatrics, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
authors.forename: Beom Hee
authors.initials: BH
authors.lastname: Lee
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Heo
authors.forename: Gu-Hwan
authors.initials: GH
authors.lastname: Kim
authors.forename: Jung-Young
authors.initials: JY
authors.lastname: Park
authors.forename: Woo-Shik
authors.initials: WS
authors.lastname: Kim
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Kang
authors.forename: Kyung Hoon
authors.initials: KH
authors.lastname: Choe
authors.forename: Won-Ho
authors.initials: WH
authors.lastname: Kim
authors.forename: Song Hyun
authors.initials: SH
authors.lastname: Yang
authors.forename: Han-Wook
authors.initials: HW
authors.lastname: Yoo
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D019556:COS Cells; D016022:Case-Control Studies; D002675:Child, Preschool; D002522:Chlorocebus aethiops; D000795:Fabry Disease / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005260:Female; D005455:Fluorescent Antibody Technique; D005787:Gene Frequency; D006801:Humans; D007231:Infant, Newborn; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D015997:Neonatal Screening; D000519:alpha-Galactosidase / Q000235:genetics* / Q000378:metabolism
chemical_list: D000519:alpha-Galactosidase