Cytogenetic and molecular investigations of an abnormal Y chromosome: evidence for a pseudo-dicentric (Yq) isochromosome.
A derivative Y chromosome was found in a 55-year-old man with Lambert-Eaton paraneoplasic pseudomyastheniform disease. Small testicles, azoospermia were noticed and hormonal level values were as in the Klinefelter syndrome. A 45,X/46,XYp+ mosaïcism was described on peripheral blood lymphocytes. Cytogenetic investigations with R-G-C- and Q-banding have been performed. In situ hybridization with the GMGY 10 DNA probe showed two copies of proximal Yp sequences. Southern blot analyses were performed using the Y DNA probes 27a, 47z, 64a7, 50f2 disclosing specific Yp and Yq sequences from the pseudoautosomal boundary to the Yq proximal portion. The der(Y) has been defined as a dicentric isochromosome for the long arm with one active and one apparently suppressed centromere. The breakpoint leading to the der(Y), has been located in the pairing segment of the Y short arm (i.e. Yp11.32). So the der(Y) was interpreted as a psu dic(Y) (qter-->cen-->p11.32 ::p11.32-->qter). There was thus an almost complete duplication of the Y chromosome.
Savary
J B
JB
Service de Génétique Humaine et Pathologie Foetale, Faculté de Médecine, Lille, France.
Vasseur
F
F
Flactif
M
M
Willatt
L
L
Lefebvre
J
J
Ferguson-Smith
M A
MA
Deminatti
M M
MM
D015139:Blotting, Southern; D002869:Chromosome Aberrations / Q000235:genetics*; D002871:Chromosome Banding; D006801:Humans; D017403:In Situ Hybridization; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014998:Y Chromosome