Screening of 20 patients with X-linked mental retardation using chromosome X-specific array-MAPH

Ludmila Kousoulidou, Sven Parkel, Olga Zilina, Priit Palta, Helen Puusepp, Maido Remm, Gillian Turner, Jackie Boyle, Hans van Bokhoven, Arjan de Brouwer, Hilde Van Esch, Guy Froyen, Hans Hilger Ropers, Jamel Chelly, Claude Moraine, Jozef Gecz, Ants Kurg, Philippos C. Patsalis

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The rapid advancement of high-resolution DNA copy number assessment methods revealed the significant contribution of submicroscopic genetic imbalances to abnormal phenotypes, including mental retardation. In order to detect submicroscopic genetic imbalances, we have screened 20 families with X-linked mental retardation (XLMR) using a chromosome X-specific array-MAPH platform with median resolution of 238 kb. Among the 20 families, 18 were experimental, as they were not previously screened with any microarray method, and two were blind controls with known aberrations, as they were previously screened by array-CGH. This study presents the first clinical application of chromosome X-specific array-MAPH methodology. The screening of 20 affected males from 20 unrelated XLMR families resulted in the detection of an unknown deletion, spanning a region of 7-23 kb. Family studies and population screening demonstrated that the detected deletion is an unknown rare copy number variant. One of the control samples, carrying approximately 6-Mb duplication was correctly identified, moreover it was found to be interrupted by a previously unknown 19 kb region of normal copy number. The second control 50 kb deletion was not identified, as this particular region was not covered by array-MAPH probes. This study demonstrates that the chromosome X-specific array-MAPH platform is a valuable tool for screening patients with XLMR, or other X-linked disorders, and emerges the need for introducing new high-resolution screening methods for the detection of genetic imbalances.

Original languageEnglish
Pages (from-to)399-410
Number of pages12
JournalEuropean Journal of Medical Genetics
Issue number6
Publication statusPublished - Nov 2007
Externally publishedYes


  • Array-MAPH
  • Chromosome X
  • Copy number changes
  • Copy number variations
  • Patient screening
  • XLMR

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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