Two Turkish siblings with intellectual disability associated with TUSC3 mutation

Objectives In recent years,homozygous mutations of the TUSC3 gene which is a tumor suppressor gene,have been reported to be associated with autosomal recessive(OR) non-syndromic intellectual disability(ID) and behavioral disorders. Methods A nine-year-old male patient presented with developmental delay of language and motor skills.His prenatal and natal history were unremarkable. The parents were cousins and his 10-year-old brother has similar clinical profile.His neurological examination revealed that he was able to take only simple commands,and his attention was very scattered.Laboratory analyses revealed normal serum lactate,pyruvate, acylcarnitine, amino acid and urine organic acid.Bilateral centrotemporal epileptic abnormality was detected in his EEG.His karyotype and microarray analysis were normal. A c.426G>A(p.Gln142Gln) homozygous mutation in the TUSC3 gene was detected in the WES.Heterozygous mutations in the TUSC3 gene were found in his parents, and homozygous in his brother. Results Patients with homozygous TUSC3 mutations have moderate to severe ID with speech delay. Cases presented with psychiatric problems such as obsessions, anxiety, sleep and eating disorders have been reported. TUSC3 gene mutation-associated ID has been described in a small number of cases in the literature, and only one case has been reported from Turkey. Conclusion TUSC3 gene mutation related non-syndromic ID is inherited autosomal recessively and is a very rare. In this article, two sibling cases from Turkey are presented to emphasize that the effective use of new genetic diagnostic methods will prevent family relapses in societies like our country where consanguineous marriages are common.
Keywords: TUSC3, intellectual disability, siblins, Turkish