Alphoidless centromere of a familial unstable inverted Y chromosome.
We report on a 3-generation pedigree in which an inverted unstable Y chromosome had no phenotypical or reproductive repercussion despite a sizable proportion of secondary aneuploidies (mainly 45, X cells) in lymphocytes. This chromosome was metacentric and had a single Cd-positive primary constriction, but occasionally assumed a normal acrocentric aspect. FISH using the probe DYZ3 revealed a single strong signal; unexpectedly, the signal was outside the primary constriction and appeared to map in the middle of p, that is, at the usual centromeric localisation. Therefore, this chromosome should be regarded as a remarkable pseudodicentric because the major alphoid array was located at the inactive centromere but not at the active one. This chromosome may have resulted from a) a transcentric inversion with the 48 bp satellite array of proximal Yq being relocated next to the Yq heterochromatin, or b) an intrachromosomal insertion of nonalphoid centromeric sequences.
Rivera
H
H
División de Genética, Instituto Mexicano del Seguro Social, Guadalajara, Jalisco, Mexico.
Vassquez
A I
AI
Ayala-Madrigal
M L
ML
Ramirez-Dueñas
M L
ML
Davalos
I P
IP
D000293:Adolescent; D000782:Aneuploidy; D002503:Centromere / Q000235:genetics*; D007446:Chromosome Inversion; D004276:DNA, Satellite; D006801:Humans; D008297:Male; D008938:Mitosis / Q000235:genetics; D010375:Pedigree; D011110:Polymorphism, Genetic; D014998:Y Chromosome
D004276:DNA, Satellite