Excess of runs of homozygosity is associated with severe cognitive impairment in intellectual disability

Ilaria Gandin, Flavio Faletra, Francesca Faletra, Massimo Carella, Vanna Pecile, Giovanni B. Ferrero, Elisa Biamino, Pietro Palumbo, Orazio Palumbo, Paolo Bosco, Corrado Romano, Chiara Belcaro, Diego Vozzi, Adamo P. D'Adamo

Research output: Contribution to journalArticlepeer-review


The harmful effects of inbreeding are well known by geneticists, and several studies have already reported cases of intellectual disability caused by recessive variants in consanguineous families. Nevertheless, the effects of inbreeding on the degree of intellectual disability are still poorly investigated. Here, we present a detailed analysis of the homozygosity regions in a cohort of 612 patients with intellectual disabilities of different degrees.Methods:We investigated (i) the runs of homozygosity distribution between syndromic and nonsyndromic ID (ii) the effect of runs of homozygosity on the ID degree, using the intelligence quotient score.Results:Our data revealed no significant differences in the first analysis; instead we detected significantly larger runs of homozygosity stretches in severe ID compared to nonsevere ID cases (P = 0.007), together with an increase of the percentage of genome covered by runs of homozygosity (P = 0.03).Conclusion:In accord with the recent findings regarding autism and other neurological disorders, this study reveals the important role of autosomal recessive variants in intellectual disability. The amount of homozygosity seems to modulate the degree of cognitive impairment despite the intellectual disability cause.

Original languageEnglish
Pages (from-to)396-399
Number of pages4
JournalGenetics in Medicine
Issue number5
Publication statusPublished - May 8 2015


  • Inbreeding
  • intellectual disability
  • runs of homozygosity

ASJC Scopus subject areas

  • Genetics(clinical)


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