Fragile X syndrome in an extended family with special reference to an affected male with Klinefelter syndrome.
We report on a large family (4 generations), with 77 studied individuals, 9 mentally retarded males, and one affected female with fragile X syndrome [fra(X)]. The analysis of 6 flanking polymorphic DNA markers showed that the affection is transmitted, through the carrier daughters to the grandsons and the greatgrandsons and that the great-grandfather is a transmitting male. This observation led us to question the importance of these clinically normal males, who are nonexpressing carriers and termed transmitting males. One propositus, described as a mentally retarded young man, had inherited identical restriction polymorphisms from his mother. Chromosome analysis showed a Klinefelter syndrome, with a fragile site in 18% of the cells leading to the conclusion that the nondisjunction occurred at the first stage of the maternal meiosis.
Voelckel
M A
MA
INSERM, Unité 242, Centre de Génétique Médicale, Hôpital d'Enfants de la Timone, Marseille, France.
Pellissier
M C
MC
Piquet
C
C
N'Guyen
C
C
Boccaccio
I
I
Philip
N
N
Mattei
J F
JF
D015342:DNA Probes; D005260:Female; D005600:Fragile X Syndrome / Q000150:complications / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D007713:Klinefelter Syndrome / Q000150:complications* / Q000235:genetics; D008297:Male; D009630:Nondisjunction, Genetic; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length
D015342:DNA Probes; D005819:Genetic Markers