A 5' splice-region mutation and a dinucleotide deletion in the lysosomal acid lipase gene in two patients with cholesteryl ester storage disease.

Autor: D Ameis, G Brockmann, R Knoblich, M Merkel, R E Ostlund, J W Yang, P M Coates, J A Cortner, S V Feinman, H Greten
Jazyk: angličtina
Rok vydání: 1995
Předmět:
Zdroj: Journal of Lipid Research, Vol 36, Iss 2, Pp 241-250 (1995)
Druh dokumentu: article
ISSN: 0022-2275
DOI: 10.1016/S0022-2275(20)39900-4
Popis: Cholesteryl ester storage disease (CESD) results from inherited deficiencies of the lysosomal hydrolase, acid lipase (LAL; E.C. 3.1.1.13). To establish the molecular defects in LAL deficiency, two unrelated probands with severely reduced LAL activity were examined. DNA amplification by reverse-transcription polymerase chain reaction and subsequent sequence analysis of LAL cDNA identified two mutant alleles. Patient 1, presenting with hepatosplenomegaly, mildly elevated liver function tests, and hyperlipidemia, was homozygous for a deletion of nucleotides 823 to 894 of the LAL cDNA. This 72-bp deletion maintained the reading frame and resulted in a loss of 24 amino acids from the LAL protein. Analysis of genomic DNA revealed that the 72 bp corresponded to an exon of the LAL gene. A single G to A point mutation at the last exon position was observed in the genomic DNA of patient 1, indicating a splicing defect with consecutive exon skipping underlying the 72-bp deletion. Patient 2 was a compound heterozygote for the 72-bp deletion and a dinucleotide deletion at positions 967 and 968. This deletion resulted in a shifted reading frame carboxyterminal of codon 296, and 43 random amino acids followed the frame shift. A premature stop at codon 339 truncated the mutant LAL protein by 34 amino acids. Allele-specific hybridization confirmed that patient 1 was homozygous for the 72-bp deletion mutation, and that patient 2 was a compound heterozygote for the 72-bp deletion and the 2-bp deletion.
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