The authors report this variant and seem to imply it’s a polymorphism. It’s seen homozygously in two out of 24 patients with propionic acidemia, but also seen in seven random chromosomes in a screen of 39 control individuals. Of the patients, one had another potential explanatory homozygous variant, the other no other was found by their sequencing. An allele frequency of 9% in controls is highly contradicting the rarity of this genetic disease.
Counting alleles, case+: 2, case-: 22, control+: 7, control-: 71 — no statistically significant difference.
The allele frequency reported in their controls differs significantly from that in GET-Evidence data (1 / 128), potentially reflecting a higher concentration of the variant in the ethnic background in their study, although the authors do not mention the ethnicity/origin of their controls.