Exclusion of the neuronal nicotinic acetylcholine receptor alpha7 subunit gene as a candidate for catatonic schizophrenia in a large family supporting the chromosome 15q13-22 locus.

The gene encoding the neuronal nicotinic acetylcholine receptor alpha7 subunit (CHRNA7) is located on chromosome 15q13.2. This region was suggested to be involved in the etiopathogenesis of: (a) schizophrenia combined with a neurophysiological deficit; (b) lithium-responsive bipolar disorder; and (c) familial catatonic schizophrenia (periodic catatonia). Therefore, members of a large family with periodic catatonia strongly supporting the chromosome 15q13-22 region were genotyped with polymorphic markers localized around the CHRNA7 locus. A recombination event distally of marker D15S144 leading to the exclusion of the CHRNA7 locus from this candidate region was detected in one branch of the pedigree. This result provides strong evidence that a gene located telomeric to CHRNA7 is causative for the pathogenesis of catatonic schizophrenia in this family.