Infantile neuroaxonal dystrophy (INAD) is a recessive disease that results in total neurologic degeneration and death in childhood. A family with two INAD sibs without mutation in PLA2G6, the known gene for INAD, was investigated. NALCN was identified as the gene responsible for the disease. The gene protein forms an ion channel that has a role in the regulation of neuronal excitability. The two patients are adults with a severe clinical phenotype. Testing infants with idiopathic severe growth retardation and neurodegeneration for NALCN mutations could benefit families. Our results add to the success of new generation genetic technologies that facilitate the identification of disease genes in even very small families. (By Prof. Asli Tolun, http://jmg.bmj.com/content/early/2013/06/06/jmedgenet-2013-101634 )