TOR1A and Neurodevelopmental delay: Here, we systematically analyse a cohort of 57 individuals from 40 families with biallelic TOR1A variants, including all previously published cases.8-17 We show that biallelic TOR1A variants cause a broad phenotypic spectrum ranging from mildly affected individuals with minimal motor impairment and normal cognition to severe cases with congenital arthrogryposis, a syndromic NDD and early death.