title: Moderate mental retardation and nonspecific dysmorphic syndrome associated with ring chromosome 9.
abstract: A ring chromosome 9 is reported in a 12-year-old, moderately mentally retarded boy. As in other ring chromosome 9 patients, the clinical stigmata are nonspecific and their expressivity is mild. The finding of two normal cells of a total of 121 cells examined favors the hypothesis of a postzygotic, mitotic origin of the ring chromosome formation.
mesh_terms: D002648:Child; D002869:Chromosome Aberrations; D002906:Chromosomes, Human, 6-12 and X; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008214:Lymphocytes / Q000648:ultrastructure; D008297:Male; D008938:Mitosis; D013577:Syndrome