Homozygous deletion in TUSC3 causing syndromic intellectual disability: A new patient

Sara Loddo, Valentina Parisi, Viola Doccini, Tiziana Filippi, Laura Bernardini, Paola Brovedani, Federica Ricci, Antonio Novelli, Agatino Battaglia

Research output: Contribution to journalArticlepeer-review

Abstract

Defects in the TUSC3 gene have been identified in individuals with nonsyndromic autosomal recessive intellectual disability (ARID), due to either point mutations or intragenic deletions. We report on a boy with a homozygous microdeletion 8p22, sizing 203kb, encompassing the first exon of the TUSC3 gene, detected by SNP-array analysis (Human Gene Chip 6.0; Affymetrix). Both nonconsanguineous parents come from a small Sicilian village and were heterozygous carriers of the microdeletion. The propositus had a few dysmorphic features and a moderate cognitive impairment. Verbal communication was impaired, with an inappropriate phonetic inventory, important phono-articolatory distortions, and bucco-phonatory dyspraxia. Comprehension was possible for simple sentences. Behavior was characterized by motor instability, high tendency to irritability and distraibility, anxiety traits, and an oppositional-defiant disorder. His parents were of normal intelligence. TUSC3 is thought to encode a subunit of the endoplasmic reticulum-bound oligosaccharyltranferase complex that catalyzes a pivotal step in the protein N-glycosylation process. TUSC3 has been recently reported as a member of the plasma membrane Mg2+ transport system, with a possible involvement in learning abilities, working memory and short- and long-term memory. This is the third family in which a deletion has been described. Although the pathogenic mechanism has not been clarified yet, our report argues for a more prominent role of TUSC3 in the etiology of intellectual disability and that deletions encompassing this gene could be more common than expected.

Original languageEnglish
Pages (from-to)2084-2087
Number of pages4
JournalAmerican Journal of Medical Genetics, Part A
Volume161
Issue number8
DOIs
Publication statusPublished - Aug 2013

Keywords

  • Autosomic recessive mental retardation (ARMR)
  • Homozygous 8p22 deletion
  • Intellectual disability
  • SNP-array
  • TUSC3 gene

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics

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