Linkage of the Gene for the Triple A Syndrome to Chromosome 12q13 Near the Type II Keratin Gene Cluster

The triple A or Allgrove's syndrome (MIM*231550) is an autosomal recessive disease characterized by the triad of adrenocorticotropic hormone (ACTH) resistant adrenal insufficiency, achalasia and alacrima. Since its first description by Allgrove et al. (1978) more than 70 cases from all over the world have been reported. The syndrome manifests itself during the first decade of life with severe hypoglycaemic episodes which can cause sudden death. The frequent association with neurological disorders presenting as a mixed pattern of upper and lower motor neuropathy, sensory impairment, autonomic neuropathy and mental retardation may result in a severely disabling disease. As an additional feature some patients have hyperkeratosis of their palms and soles. We have performed a systematic genome linkage scan in eight triple A families of which three were consanguineous [including the large highly inbred kindred described by Moore et al. (1991)]. We obtained conclusive evidence for linkage of the triple A syndrome locus to markers on chromosome 12q13 (D12S368, θmax = 0, Zmax = 10.81) with no indication of genetic heterogeneity. Haplotype and multipoint analyses suggest that the gene is located on a chromosomal segment flanked by the markers D12S1629 and D12S312 which are 6 cM apart. This region harbors the type II keratin gene cluster, and potential candidate genes include SCN8A and HOXC genes.