  Liu et al. recently reported that biallelic mutations in DAGLB are
responsible for autosomal recessive early-onset Parkinson's disease. They
identified six patients carrying DAGLB mutations, all of Chinese origin and
presenting with typical Parkinson disease. No additional cases outside China
have been reported so far.To assess the causality of DAGLB in our cohort, we
used data mining in the exomes of 684 index cases with either autosomal
recessive or sporadic early onset Parkinson disease (< 50 years). We identified
a homozygous p.Pro357Leu missense variant in a single consanguineous PD case.
This mutation predicted deleterious, affects a conserved amino acid localized
in the catalytic domain of the protein nearby the pathological p.Asp363Gly
mutation described in the previous paper. As the most frequent genes involved
in AR-PD (PRKN, PINK1), the DAGLB-associated disease presents and evolves like
typical PD.This work reinforces the fact that DAGLB is involved in early onset
Parkinson disease, but given the fact that we identified a single patient among
684 index cases screened, we conclude that DAGLB is a very rare cause of early
onset autosomal recessive Parkinson disease. However, we demonstrate that,
mutations in DAGLB are not limited to the Chinese population but can also
account for PD in North Africa.We feel that these new data indicate that DAGLB
variants should be considered in non-Chinese cases with early-onset typical
Parkinson disease.
