Deleting KCTD13, a gene in the autism risk region 16p11.2, has little effect on brain or head size in mice, according to a new study1.
“We were very surprised when we didn’t see changes in brain size or cell proliferation,” says lead investigator Craig Powell, Ed and Sue Rose Distinguished Professor in Neurology at the University of Texas Southwestern in Dallas.
However, the study reveals a new function for KCTD13: It limits the levels of an enzyme called RhoA, which controls the construction of the cell skeleton. Loss of KCTD13 increases RhoA, decreases the number of synapses — the connections between neurons — and stifles communication among the cells. Blocking RhoA with a drug restores neuronal communication. The results appeared 1 November in Nature.
The study also suggests it is unlikely that there is a single gene in the 16p11.2 chromosomal region that accounts for all of the traits seen in people with a deletion of the region.
“It’s probably not KCTD13 alone modulating all the phenotype of the 16p11.2 rearrangement,” says Alexandre Reymond, director of the Center for Integrative Genomics at the University de Lausanne in Switzerland, who was not involved in the study.”
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