A boy with the Rett syndrome?

A 13-year-old Kuwaiti boy met all necessary and almost all supportive criteria for the Rett syndrome. Electron microscopy of muscle biopsy specimen revealed abnormal mitochondria, a finding that has recently been reported for girls with the Rett syndrome. The results of other laboratory investigations were normal, besides a blood ammonia level of 100 microM/L. The mitochondrial changes observed in girls may be the consequence of an X-borne gene mutation, in which case only the female zygote survives because of the normal allele on the second X-chromosome. However, another genetic possibility discussed is inheritance according to "metabolic interference" of an X-borne allele, which does not rule out the possibility of a male being affected. We assume that the case reported might be a male variant of the Rett syndrome.