Fig. 2

Pedigrees from five MJD/SCA3 disease families showing repeat sizes determined by RED and PCR

RED product sizes (bp) are indicated in bold characters (upper numbers), whereas repeat copy number of expansions detected by PCR are indicated below in italics. Two PCR alleles in the normal range are designated N, whereas cases with only one detectable size are designated n, ? Individuals marked A are clinically asymptomatic but show RED and PCR expansions. Individuals marked B show RED products in the MJD/SCA3 range, but are asymptomatic and lack detectable PCR expansions. Individual C was first judged to be affected, but did not show either PCR or RED expansions. She was therefore reevaluated and found to be unaffected. Individual D is affected and has a RED expansion but shows only one short PCR product and no expansion. Individual E has the longest repeat size of 80 copies and also the longest RED product of 270 bp. Individual F is clinically unaffected at the age of 45, with a repeat size of 64 copies.