Cytogenetic characterization of an extra structurally abnormal chromosome associated with severe mental retardation: inv dup (15) (q13)

Hereditas. 1998;129(1):1-5. doi: 10.1111/j.1601-5223.1998.t01-1-00001.x.


We have studied an extra structually abnormal chromosome (ESAC) in a 13 years old boy with profound mental, psychomotor and speech retardation, behavioral problems, seizures and abnormal electroencephalogram. The examination of the bisatellited ESAC with chromosome banding demonstrated that the karyotype was: 47, XY, +inv dup (15) (pter-->q13::q13-->pter). The cytogenetic characterization of the inv dup (15) is reported with special emphasis on the usefulness of DA/DAPI staining when G-banding is sequentially performed to discard possible heteromorphisms in DA/DAPI positive chromosomes, and the importance of Ag-NOR heteromorphisms to ascertain the maternal origin of the inv dup (15). A U-type exchange between two non-sister chromatids is proposed as its mechanism of formation. The clinical features of the case were consistent with those previously reported in similar cases.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Chromosome Aberrations*
  • Chromosome Banding
  • Chromosome Inversion*
  • Chromosome Mapping
  • Chromosomes, Human, Pair 15*
  • Gene Duplication
  • Humans
  • Intellectual Disability / genetics*
  • Intellectual Disability / pathology
  • Karyotyping
  • Male
  • Mental Disorders / genetics
  • Seizures / genetics
  • Speech Disorders / genetics