Ry and 4.15 of EU chromosomes in the ExAC Browser, and there were 83 reported instances of homozygosity. The laboratory that interpreted this variant as B invoked the MAF > 5 (BA1) as standalone criteria and noted the presence of homozygotes in population databases. Like SPG7, this might represent an allele that is more likely to be pathogenic when it is found to be compound heterozygous with a