title: Two different structural abnormalities of chromosome 13 in offspring of chromosomally normal parents with two fragile sites.
abstract: Two siblings were found with different structural abnormalities involving their maternally inherited chromosome 13. The proband exhibited a ring 13 and a small fragment: 46,XX,r(13) (p11q34), +f, while her clinically normal brother carried a dicentric Robertsonian translocation: 45,XY,dic(13;15) (p11;p11). Both parents had normal karyotypes in peripheral blood and skin fibroblasts. The structural abnormalities of chromosome 13 may be due to an unstable gonadal 13;15 translocation in the mother. In addition, two autosomal fragile sites were segregating in this family. The mother had a fragile (16) (q22) which was inherited by the proband. The father and paternal grandmother possessed a fragile (12)(q13) which was not inherited by either child. The expression of both fragile sites was dependent on culture conditions.
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics; D000328:Adult; D002869:Chromosome Aberrations; D043283:Chromosome Fragile Sites; D002873:Chromosome Fragility; D002901:Chromosomes, Human, 13-15; D002902:Chromosomes, Human, 16-18; D002906:Chromosomes, Human, 6-12 and X; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D014178:Translocation, Genetic