Chromosome 18q paracentric inversion in a family with mental retardation and hearing loss

Kim M. Keppler-Noreuil, Andrew J. Carroll, Sara C. Finley, Maria Descartes, Jannine D. Cody, Barbara R. DuPont, Charles T. Gay, Robin J. Leach

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


We report on a mother and child with a paracentric inversion of the long arm of chromosome 18: 46,XX,inv(18)(q21.1q23). The child had findings in common with those seen in 18q- syndrome including: microcephaly, epicanthal folds, midface hypoplasia, and abnormally modeled ears, dermatoglyphic whorls on fingertips, clubfeet, hearing loss, and developmental delay. The mother and several maternal relatives had mild mental retardation and hearing loss. Magnetic resonance imaging of the child's brain showed abnormal myelination. Molecular studies including PCR-based markers for the MBP locus and fluorescent in situ hybridization with a P1 genomic clone on mother and child demonstrated only one copy of the MBP locus (18q23) with the deletion extending beyond the MBP locus. Therefore, the deletion in the MBP region may account for the abnormal myelination seen in the patient. The other clinical findings, including mental retardation and hearing loss in this family, may reflect disruption of distal or proximal genes within the deleted MBP region or at the more proximal breakpoint 18q21.1, and may represent a contiguous gene syndrome. Further study of this family may help define those genes functioning in the MBP region that contribute to the phenotype of 18q- syndrome.

Original languageEnglish (US)
Pages (from-to)372-378
Number of pages7
JournalAmerican Journal of Medical Genetics
Issue number5
StatePublished - Apr 13 1998


  • 18q paracentric inversion
  • 18q- syndrome
  • Abnormal
  • Myelin basic protein (MBP)

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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