PT - JOURNAL ARTICLE AU - J C MacMillan AU - J Voisey AU - S C Healey AU - N G Martin TI - Mendelian segregation of normal CAG trinucleotide repeat alleles at three autosomal loci AID - 10.1136/jmg.36.3.258 DP - 1999 Mar 01 TA - Journal of Medical Genetics PG - 258--259 VI - 36 IP - 3 4099 - http://jmg.bmj.com/content/36/3/258.short 4100 - http://jmg.bmj.com/content/36/3/258.full SO - J Med Genet1999 Mar 01; 36 AB - Segregation ratio distortion (SRD) with preferential transmission of expanded CAG alleles has been reported in Machado-Joseph disease (MJD/SCA3), spinocerebellar ataxia type I (SCA1), and dentatorubral-pallidoluysian atrophy (DRPLA). We have examined the transmission frequencies of alleles in normal heterozygotes at these disease loci in 377 pairs of twins and their parents and find no evidence for SRD.