Ługowska A, Ponińska J, Krajewski P, Broda G, Płoski R. Population carrier rates of pathogenic ARSA gene mutations: is metachromatic leukodystrophy underdiagnosed?
PLoS One 2011;
6:e20218. [PMID:
21695197 PMCID:
PMC3112151 DOI:
10.1371/journal.pone.0020218]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 04/27/2011] [Indexed: 01/31/2023] Open
Abstract
Background
Metachromatic leukodystrophy (MLD) is a severe neurometabolic disease caused mainly by deficiency of arylsulfatase A encoded by the ARSA gene. Based on epidemiological surveys the incidence of MLD per 100 000 live births varied from 0.6 to 2.5. Our purpose was to estimate the birth prevalence of MLD in Poland by determining population frequency of the common pathogenic ARSA gene mutations and to compare this estimate with epidemiological data.
Methodology
We studied two independently ascertained cohorts from the Polish background population (N∼3000 each) and determined carrier rates of common ARSA gene mutations: c.459+1G>A, p.P426L, p.I179S (cohort 1) and c.459+1G>A, p.I179S (cohort 2).
Principal Findings
Taking into account ARSA gene mutation distribution among 60 Polish patients, the expected MLD birth prevalence in the general population (assuming no selection against homozygous fetuses) was estimated as 4.0/100 000 and 4.1/100 000, respectively for the 1st and the 2nd cohort with a pooled estimate of 4.1/100 000 (CI: 1.8–9.4) which was higher than the estimate of 0.38 per 100 000 live births based on diagnosed cases. The p.I179S mutation was relatively more prevalent among controls than patients (OR = 3.6, P = 0.0082, for a comparison of p.I179S frequency relative to c.459+1G>A between controls vs. patients).
Conclusions/Significance
The observed discrepancy between the measured incidence of metachromatic leukodystrophy and the predicted carriage rates suggests that MLD is substantially underdiagnosed in the Polish population. The underdiagnosis rate may be particularly high among patients with p.I179S mutation whose disease is characterized mainly by psychotic symptoms.
Collapse