LA-Belize family is described with linkage in this region, with a peak LOD of around 3.5-3.6.
These authors describe mutations in this gene linked to juvenile myoclonic epilepsy. They also note several coding polymorphism, R159W, R182H and I619L — this variant (182H) had an allele frequency of 11%. They note that the R182H polymorphism segregates with disease in the LA-Belize family, but this not surprising as the family was already known to have linkage in this region.
The authors do not appear to interpret this variant as disease-causing, as they report no effect in functional studies in this manner: “Mutations associated with JME (P77T/R221H, P77T, D210N, R221H, F229L, D253Y) significantly reversed the cell-death effect of EFHC1 at 36 and 48 h after transfection, whereas the polymorphisms that occurred both in individuals affected with JME and in controls (R159W, R182H, I619L) largely maintained the cell-death effects.” OMIM appears to have incorrectly referenced this paper as suggesting that the variant causes susceptibility to juvenile myoclonic epilepsy.