Sister chromatid exchange analysis in the Prader-Labhart-Willi syndrome

The number of sister chromatid exchanges (SCE) and cell kinetics in lymphocytes were investigated from 16 Prader-Labhart-Willi syndrome (PLWS) patients [8 with 15q12 deletion (4 females, 4 males; mean age = 12.9y with age range of 0.3 to 24y), and 8 non-deletion (2 females, 6 males; means age = 16.8y with age range of 5 to 26y)], 18 parents of PLWS patients and age-matched control individuals. The average SCE frequency and standard deviation in PLWS patients with and without the chromosome 15 deletion was 6.6 +/- 1.3 and 6.2 +/- 0.8, respectively. Therefore no significant difference in SCE frequency or replicative index was found between the two PLWS subgroups. There was also no significant difference in SCE frequency or replicative index between the 16 PLWS patients and age-matched control subjects. The average SCE frequency and standard deviation in 8 fathers who were previously identified to have donated the chromosome 15 with the deletion in the child was 7.5 +/- 1.2, which was not significantly different from 8.5 +/- 2.0 seen in age-matched control subjects. There was also no significant difference in the SCE frequency or replicative index of 18 parents of PLWS patients with and without the chromosome 15 deletion when compared with age-matched control subjects.