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335.4 kb microduplication in chromosome band Xp11.2p11.3 associated with developmental delay, growth retardation,

Viola Alesi1, Marta Bertoli, Giuseppe Barrano

  • 1S. Pietro Fatebenefratelli Hospital, UOSD Medical Genetics, Rome, Italy.

Gene
|May 29, 2012
PubMed

Insights

A small X chromosome microduplication in males is linked to developmental delays. This finding suggests ZNF81 gene over-expression may cause X-linked mental retardation.

Area of Science:

  • Genetics
  • Neurodevelopmental Disorders
  • Human Molecular Genetics

Background:

  • X-linked mental retardation (XLMR) accounts for approximately 10% of intellectual disability cases in males.
  • The Xp11.2p11.3 region is implicated in a significant portion of XLMR cases, though specific pathogenic genes remain largely unidentified.
  • ZNF81, a gene within this region, has been previously associated with mental retardation through various mutation types.

Observation:

  • A 3-year-old boy presented with developmental delay, autistic features, and growth and speech delays.
  • Array comparative genomic hybridization (array-CGH) identified a 335.4 kb microduplication on the X chromosome (Xp11.2p11.3).
  • This microduplication encompasses the ZNF81, ZNF182, and SPACA5 genes.

Findings:

  • The identified microduplication is the smallest reported in the Xp11.2p11.3 region to date.
  • Mutations and larger duplications in this region, including those involving ZNF81, are known to be associated with mental retardation.
  • Over-expression of ZNF81 has been previously observed in a related case.

Implications:

  • This case suggests that even small microduplications in Xp11.2p11.3 can lead to developmental disorders.
  • The findings point towards ZNF81 over-expression as a potential pathogenic mechanism in X-linked mental retardation.
  • Further research is warranted to elucidate the role of ZNF81 in neurodevelopment and its contribution to XLMR.

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