Frequency of qh+ chromosomal variants in a) radioexposed, b) Down syndrome and c) control subjects.
"Paranormal" variants of human chromosomes, devoid of phenotypical effects (since what appears to vary is heterochromatic, non-genic DNA) are known to be heritable. Some very large variants (especially the qh+ variants on chromosomes 1 and possibly 16 and Y) were reported to be associated with increased reproductive pathology (sterility, fetal wastage, chromosomal aberrations). These variants are currently assessed by the C-band techniques; very large C-bands correspond to morphological alterations (elongation or deformation) of the chromosome. A study of qh+ morphological variants of chromosomes 1, 9 and 16 in 40 professionally radioexposed subjects, in 40 Down-syndrome patients and in 40 controls is reported, indicating that the frequency of each variant is lowest among controls, intermediate among professionally radioexposed subjects and highest among Down-syndrome patients. These findings, if confirmed, suggest a possible use of the qh+ variants as heritable indicators of chromosomal damage.
D002869:Chromosome Aberrations; D002871:Chromosome Banding; D002900:Chromosomes, Human, 1-3; D002902:Chromosomes, Human, 16-18; D002906:Chromosomes, Human, 6-12 and X; D004314:Down Syndrome / Q000235:genetics*; D004781:Environmental Exposure; D006801:Humans; D008297:Male; D010564:Personnel, Hospital; D011871:Radiology; D014998:Y Chromosome