Mutation of the sterol 27-hydroxylase gene (CYP27) results in truncation of mRNA expressed in leucocytes in a Japanese family with cerebrotendinous xanthomatosis

摘要

OBJECTIVES—AJapanese family with cerebrotendinous xanthomatosis (CTX) wasinvestigated for a sequence alteration in the sterol 27-hydroxylase gene (CYP27). The expression ofCYP27 has been mostly explored usingcultured fibroblasts, prompting the examination of the transcripts fromblood leucocytes as a simple and rapid technique.
METHODS—An alterationin CYP27 of the proband was searched for bypolymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and subsequent sequencing. Samples ofRNA were subjected to reverse transcriptionPCR (RT-PCR) and the product of the proband was amplified with nestedprimers and sequenced.
RESULTS—A homozygous Gto A transition at the 5' end of intron 7 was detected in the patient.In RT-PCR analysis, only a truncated transcript was detected in thepatient, whereas both normal and truncated transcripts were detected inthe siblings. The sequencing of the patient's cDNA fragment discloseda direct conjuction of exon 6 and exon 8.
CONCLUSION—Themutation at splice donor site and the truncation of mRNA were identicalwith those of a recently reported Italian patient, although differentin symptomatology. The application of blood leucocytes can be a simpletechnique on analysing a constructive abnormality ofCYP27 mRNA.