title: Fabry disease: incidence of the common later-onset α-galactosidase A IVS4+919G→A mutation in Taiwanese newborns--superiority of DNA-based to enzyme-based newborn screening for common mutations.
abstract: Fabry disease is a panethnic, X-linked, inborn error of glycosphingolipid metabolism resulting from mutations in the α-galactosidase A gene (GLA) that lead to the deficient activity of the lysosomal enzyme, α-galactosidase A (α-Gal A). Affected males with no α-Gal A activity have the early-onset classic phenotype, whereas those with residual activity present with the later-onset subtype. Recently, we reported that newborn enzyme-based screening using dried blood spots (DBS) in Taiwan revealed a high incidence of newborn males who had the GLA c.936+919G→A (IVS4+919G→A) mutation. This lesion causes cryptic splicing, markedly reducing the amount of wild-type GLA mRNA, and has been found in males with the later-onset Fabry phenotype, manifesting as cardiac, renal and/or cerebrovascular disease. To more accurately determine the incidence of the IVS4+919G→A mutation, 20,063 consecutive newborns were screened by a deoxyribonucleic acid (DNA)-based assay. Of the 10,499 males, 12 (1/875) and 24 of the 9,564 females (1/399) had the mutation. On the basis of these frequencies, the previous newborn enzyme-based DBS screening (cutoff: <30% of the normal mean) only identified 67% and 17% of mutation-positive males and females, respectively. The mean DBS α-Gal A activities in the mutation-positive males and females were 23% (1.54 U) and 55% (3.63 U) of normal mean male/female values, respectively. These studies confirm the high incidence of the IVS4+919G→A mutation in the Taiwanese population and indicate that its detectability by enzyme-based DBS screening is unreliable, especially in females. These studies emphasize the superiority of DNA-based newborn screening for common mutations, particularly for X-linked diseases.
authors.affiliation: Department of Medical Genetics and Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Yin-Hsiu
authors.initials: YH
authors.lastname: Chien
authors.forename: Ni-Chung
authors.initials: NC
authors.lastname: Lee
authors.forename: Shu-Chuan
authors.initials: SC
authors.lastname: Chiang
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Desnick
authors.forename: Wuh-Liang
authors.initials: WL
authors.lastname: Hwu
mesh_terms: D044466:Asian People / Q000235:genetics*; D004252:DNA Mutational Analysis; D000795:Fabry Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D005820:Genetic Testing; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D015997:Neonatal Screening; D012326:RNA Splicing; D013624:Taiwan / Q000453:epidemiology; D000519:alpha-Galactosidase / Q000235:genetics*
chemical_list: D000519:alpha-Galactosidase