Identification of a DAGLB Mutation in a Non-Chinese Patient with Parkinson's Disease.

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.