Familial Dysautonomia: Rare Disease or More Common than You Think? [20D]. (May 2018) - Bardos, Jonah D.
Abstract : INTRODUCTION: Familial Dysautonomia (FD) is an autosomal recessive disorder affecting the sensory and autonomic nervous systems causing life threatening autonomic crises, hypotonia, and progressive neuronal degeneration. Currently, carrier testing for FD is recommended for the Ashkenazi Jewish (AJ) population. A joint ACOG/ACMG statement highlighted the increasingly multi-ethnic society as consideration for pan-ethnic carrier testing, and recent ACOG committee opinion states that pan-ethnic carrier testing is a reasonable strategy. This study assesses how many non-AJ individuals screened positive for FD when pan-ethnic carrier screening was implemented. METHODS: Retrospective database analysis of individuals that received expanded carrier testing utilizing a genotyping panel for two pathologic variants of FD (c.2204+6T>C, R696P) was performed. Expected number of positive carriers for FD in AJ and non-AJ groups were calculated and compared to observed rates. Chi-square analysis was performed to assess for statistical significance (p < 0.01). RESULTS: A total of 71, 243 individuals were tested for FD. A higher than expected number of non-AJ individuals screened positive for FD (38 observed vs 14.05 expected, p<0.001). The number of AJ individuals that screened positive was consistent with expected values (33 observed vs 32.08 expected, p<0.86). CONCLUSION: Non-AJ carriers of FD were more common than expected in this cohort. Pan-ethnic expanded carrier testing will increase the detection of carriers for FD compared with current ethnicity based screening recommendations. Importantly, carriers of FD, who would be missed by ethnicity based testing convention, will be identified allowing for more complete genetic counseling and family planning options for those who choose testing.