Gene Discovered for New form of Intellectual Disability

Under the direction of Dr. John Vincent, CAMH discovered a new form of intellectual disability involving mental retardation (MR) along with the eye defect retinitis pigmentosa (RP). Dr. Vincent and his team also discovered the previously unidentified gene that causes this disorder, CC2D2A.  This discovery will help understand the developmental and biological processes involved in brain development, and may help identify ways to diagnose and treat intellectual disabilities.

As Dr. Vincent explains, most genes for intellectual disabilities that have been found so far are on the X chromosome, but this mutation was found on the autosome (The 22 pairs of non-sex chromosomes, that make up the 46 chromosomes in the human body). Autosomal-recessive inheritance (where both mother and father carry a gene mutation on one chromosome, but both maternal and paternal copies must be passed on to the offspring to cause the disorder) is believed to be relatively common in intellectual disability, though only four genes causing this type of disability have been identified to date.

”What’s really exciting is that the new gene, CC2D2A, encodes a protein with domains similar to those found in one of the previous four autosomal recessive MR genes.  This link could suggest a common function that is essential for normal brain development,” says Dr. Vincent.

Dr. Vincent and his team will continue exploring these initial findings, to help identify more people with mutations affecting the CC2D2A gene.  This additional research will provide scientists more clues to understand, diagnose and treat intellectual disabilities.

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