Linkage Analysis of Chromosome 7p22 Region in a Chinese Pedigree with Familial Hyperaldosteronism Type Ⅱ / 中华高血压杂志

ABSTRACT

Background Familial hyperaldosteronism type Ⅱ(FH-Ⅱ) is characterized by autosomal dominant inheritance and hyperaldosteronism.Linkage analysis demonstrated chromosome 7q22 most likely harbor the genetic defect.Objective To identify the disease locus in a Chinese pedigree with FH-Ⅱ using genetic linkage analysis.Methods Haplotypes of the FH-Ⅱ pedigree were analyzed using four microsatellite markers(D7S531,D7S2521,D7S511,D7S481) at 7p22 to determine the critical region,and multipoint logarithm of odds(LOD) scores were calculated to assess linkage with FH-Ⅱ.Results Several members(affected members) in the family had hypertension,hypokalemia,hyperaldosteronism,low renin activity.Hypertension and hypokalemia was improved by spironolactone test.Dexamethasone suppression test was performed but without clinical or hyperaldosteronism improvement in three affected members,confirmed FH-Ⅱ family pedigree.The same haplotypes D7S531(ac,n=24)-D7S2521(ac,n=11)-D7S511(ca,n=21)-D7S481(ac,n=16) were shared by all known affected members and one suspicious member,but also by one unaffected member of the family,making it unlikely that this region contains the causative gene mutation.In this FH-Ⅱ family,the LOD scores of the four markers were