To screen the gene mutation in β and γ subunits of the epithelial sodium channel (ENaC) of a Chinese family, some of whose members are clinically diagnosed as suffering from Liddle syndrome.
Twelve family members were recruited to the study. Among them, two brothers had been clinically diagnosed as suffering from Liddle syndrome. Peripheral blood samples were collected from all members of the family and total genomic DNA was prepared for genetic analysis. Polymerase chain reaction (PCR) was used for amplifying the last exon of β (codon 513–673) and γ (codon 503–632) subunits of the ENaC gene. PCR products were purified and subjected to a direct DNA sequence analysis.
Genetic analysis of the βENaC gene revealed a missense mutation of CCC to CTC at codon 616 in four middle-aged men of the second generation and one young woman of the third generation. There was no mutation of the γENaC gene in any of the individuals examined.
Through direct DNA sequencing analysis, we diagnosed the disease present in five members of a Chinese family as Liddle syndrome, and excluded it in some other young offspring suffering from the monogenic disease. Our results provide further evidence that Pro616 is a critical amino acid that has a key role in the inhibition of sodium channel activity.
aShanghai Institute of Hypertension, Ruijin Hospital, Shanghai Second Medical University, Shanghai and bSanmenxia Hospital, Sanmenxia, Henan province, People's Republic of China.
Received 30 August 2000
Revised 28 December 2000
Accepted 16 January 2001
Sponsorship: This study was supported by grants by the Chinese High Tech Program (102-10-02-03, Z19-01-03-01A) and a grant from the National Key Program on Basic Research (G19980510) from the Ministry of Science and Technology, People's Republic of China.
Correspondence and request for reprints to Dr Ding L. Zhu, Shanghai Institute of Hypertension, 197 Ruijin 2nd Road, Shanghai 200025, P.R. China. Tel: +86 21 64370045 ext 663201; fax: +86 21 64314015; e-mail: firstname.lastname@example.org