A mutation in the gene for an enzyme (BCKDK) that blocks the breakdown of certain amino acids has been linked to a very rare form of autism, epilepsy and intellectual disability. Thus, these patients have abnormally low levels of these amino acids. When this gene was disabled in mice, and they were raised on a diet low in these amino acids, the animals showed an abnormal pattern of amino acids in their blood, and they displayed seizures, as do the patients. Importantly, feeding the mutant mice a diet enriched in these amino acids reduced the seizures. Thus, dietary manipulation could induce a key symptom as well as cure it in the mutant mice. Unfortunately, the investigators did not report any analysis of the core autism-like behavioral symptoms: deficits in social interaction or verbal communication, or increases in repetitive behaviors. It was reported on the SAFARI site today that these researchers have started to treat their patients with the amino acid supplements, and have normalized their blood levels, but “they don’t yet know if symptoms improve”. Thus far, only 3 families are known with this disorder, so this is indeed a rare condition.