The parental origin of the single X chromosome in Turner syndrome: lack of correlation with parental age or clinical phenotype.
We have used X- and Y-linked RFLPs to determine the origin of the single X chromosome in 25 live-born individuals with Turner syndrome. We determined that 18 individuals retained a maternal X (Xm) and that seven retained the paternal X (Xp). No occult mosaicism was detected. We found no differences in either maternal or paternal ages for the two groups. The ratio of maternal X to paternal X is just over 2:1, which is consistent with the expected proportion of meiotic or mitotic products, with equal loss at each step, given the nonviability of 45,Y. Six phenotypic or physiologic characteristics were assessed: (1) birth weight, (2) height percentile at time of testing, (3) presence of a webbed neck, (4) cardiovascular abnormalities, (5) renal abnormalities, and (6) thyroid autoimmunity. There were no significant differences in birth weights or heights between the girls who retained the maternal X or the paternal X. In addition, no differences between the groups could be appreciated in the incidence of the physical, anatomic, or physiologic parameters assessed.
Mathur
A
A
Department of Pediatrics, University of California School of Medicine, Los Angeles.
Stekol
L
L
Schatz
D
D
MacLaren
N K
NK
Scott
M L
ML
Lippe
B
B
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D010331:Paternal Age; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D014424:Turner Syndrome / Q000235:genetics*; D014960:X Chromosome