Researchers at the University of Haifa and the Rambam Genetic Institute in collaboration with researchers at the faculty of medicine in the Technion have discovered a new genetic mutation linked to the development of autism, movement disorders and cognitive impairment.
The researchers’ poster presentation on the findings is entitled, Founder variant in Tubulin Binding Co-factor B is associated with Autism Spectrum and Hereditary Spastic Paraparesis.
“We describe a novel form of HSP associated with autism and intellectual disability (ID), secondary to a founder variant in TBCB p.Tyr197Asn with a high carrier rate in Ashkenazi Jews,” the researchers wrote.
“Our results show that TBCB has a role in CNS (central nervous system) development in humans and Drosophila and potentially in axonal function.”
HSP is a group of inherited progressive conditions that cause weakness and spasticity in the leg muscles. In some forms of HSP, spastic paraparesis is accompanied by additional issues such as cognitive impairment, peripheral neuropathy and retinal changes, according to the Cleveland Clinic.
The mutation, discovered in the TBCB gene (Tubulin Folding Cofactor B) by researchers Dr. Sharon Bratman-Morag and Dr. Karin Weiss, is present in one out of every 80 Ashkenazi Jews. It is also found among Sephardic Jews but is not as common.
Carrier frequency in the Ashkenazi Jewish (AJ) population is 1.3% according to gnomAD(v4.1) database compared with 0.03% in the general population.
The mutated gene is an inherited syndrome in an autosomal recessive form, the researchers said. There is a 25 percent risk of a child being born with its associated neurodevelopmental problems if both parents carry a copy of the defective gene.
Further research is needed to understand the disease mechanisms and genotype-phenotype correlations,” the researchers added.
The Israeli Health Ministry’s “basket” of covered services, medications and tests now includes the uniform genetic testing that reveals this mutation. The test is available free of charge at Israeli HMOs (kupot holim) and genetic institutes are part of the general uniform genetic survey.
