Localization of the gene for familial dysautonomia on chromosome 9 and definition of DNA markers for genetic diagnosis

Familial dysautonomia (DYS), the Riley–Day syndrome, is an autosomal recessive disorder characterized by developmental loss of neurons from the sensory and autonomic nervous system. It is limited to the Ashkenazi Jewish population, where the carrier frequency is 1 in 30. We have mapped the DYS gene to chromosome 9q31–q33 by linkage with ten DMA markers in 26 families. The maximum lod score of 21.1 with no recombinants was achieved with D9S58 . This marker also showed strong linkage disequilibrium with DYS, with one allele present on 73% of affected chromosomes compared to 5.4% of controls (χ=3142, 15 d.f. p