Bi-allelic TTI1 variants cause an autosomal-recessive neurodevelopmental disorder with microcephaly.

Fiche publication

Date publication

mars 2023

Journal

American journal of human genetics

Auteurs

Membres identifiés du Cancéropôle Est :
Pr THAUVIN-ROBINET Christel

Tous les auteurs :
Serey-Gaut M, Cortes M, Makrythanasis P, Suri M, Taylor AMR, Sullivan JA, Asleh AN, Mitra J, Dar MA, McNamara A, Shashi V, Dugan S, Song X, Rosenfeld JA, Cabrol C, Iwaszkiewicz J, Zoete V, Pehlivan D, Akdemir ZC, Roeder ER, Littlejohn RO, Dibra HK, Byrd PJ, Stewart GS, Geckinli BB, Posey J, Westman R, Jungbluth C, Eason J, Sachdev R, Evans CA, Lemire G, VanNoy GE, O'Donnell-Luria A, Mau-Them FT, Juven A, Piard J, Nixon CY, Zhu Y, Ha T, Buckley MF, Thauvin C, Essien Umanah GK, Van Maldergem L, Lupski JR, Roscioli T, Dawson VL, Dawson TM, Antonarakis SE

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/36724785

Résumé

Telomere maintenance 2 (TELO2), Tel2 interacting protein 2 (TTI2), and Tel2 interacting protein 1 (TTI1) are the three components of the conserved Triple T (TTT) complex that modulates activity of phosphatidylinositol 3-kinase-related protein kinases (PIKKs), including mTOR, ATM, and ATR, by regulating the assembly of mTOR complex 1 (mTORC1). The TTT complex is essential for the expression, maturation, and stability of ATM and ATR in response to DNA damage. TELO2- and TTI2-related bi-allelic autosomal-recessive (AR) encephalopathies have been described in individuals with moderate to severe intellectual disability (ID), short stature, postnatal microcephaly, and a movement disorder (in the case of variants within TELO2). We present clinical, genomic, and functional data from 11 individuals in 9 unrelated families with bi-allelic variants in TTI1. All present with ID, and most with microcephaly, short stature, and a movement disorder. Functional studies performed in HEK293T cell lines and fibroblasts and lymphoblastoid cells derived from 4 unrelated individuals showed impairment of the TTT complex and of mTOR pathway activity which is improved by treatment with Rapamycin. Our data delineate a TTI1-related neurodevelopmental disorder and expand the group of disorders related to the TTT complex.