Molecular analysis of ABCD1 gene in Indian patients with X-linked adrenoleukodystrophy

Abstract

Background: X-linked Adrenoleukodystrophy (X-ALD), with an incidence of 1:14,000 is the most frequent monogenic demyelinating disorder worldwide. The principal biochemical abnormality in X-ALD is the increased levels of saturated, unbranched very long chain fatty acids (VLCFA). It is caused by mutations in ABCD1 gene. No molecular data on X-ALD is available in India and mutational spectrum in Indian patients is not known.

Methods: We standardized conformation sensitive gel electrophoresis (CSGE) method to detect mutations in ABCD1 gene in twenty Indian patients with X-ALD. The results were confirmed by sequencing. Genotype-phenotype correlation was also attempted. Prenatal diagnosis (PND) in one family was done using chorionic villi (CV) sample at 12 weeks of gestation.

Results: Out of twenty, causative mutations could be identified in twelve patients (60%). Six reported and four novel mutations were identified. Three polymorphisms were also observed. No hot spot was found. No significant genotype-phenotype correlation could be established.

Conclusions: The study identified the mutation spectrum of Indian X-ALD patients, which enabled us to offer accurate genetic counseling, carrier detection and prenatal diagnosis where needed.