title: A 5' splice-region mutation and a dinucleotide deletion in the lysosomal acid lipase gene in two patients with cholesteryl ester storage disease.
abstract: 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.
authors.affiliation: Department of Medicine, University Hospital Eppendorf, Hamburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Ameis
authors.forename: G
authors.initials: G
authors.lastname: Brockmann
authors.forename: R
authors.initials: R
authors.lastname: Knoblich
authors.forename: M
authors.initials: M
authors.lastname: Merkel
authors.forename: R E
authors.initials: RE
authors.lastname: Ostlund
authors.forename: J W
authors.initials: JW
authors.lastname: Yang
authors.forename: P M
authors.initials: PM
authors.lastname: Coates
authors.forename: J A
authors.initials: JA
authors.lastname: Cortner
authors.forename: S V
authors.initials: SV
authors.lastname: Feinman
authors.forename: H
authors.initials: H
authors.lastname: Greten
mesh_terms: D000328:Adult; D000483:Alleles; D001483:Base Sequence; D015217:Cholesterol Ester Storage Disease / Q000201:enzymology / Q000235:genetics*; D017931:DNA Primers; D017353:Gene Deletion; D006801:Humans; D008049:Lipase / Q000235:genetics*; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D017421:Sequence Analysis
chemical_list: D017931:DNA Primers; D008049:Lipase