Compound heterozygous and digenic inheritance in early-onset Parkinson's disease: a systematic review.

What was studied

This systematic review looked at genes in early-onset Parkinson's disease. It covered compound heterozygous cases and digenic cases. It included 106 studies. They held 304 compound heterozygous cases and 16 digenic cases. The review followed PRISMA guidelines.

What they found

PRKN was the top gene in the compound heterozygous cases. Structural variants were found in 205 of 241 PRKN cases. Many were deletions of whole exons. PINK1 was the next most common gene. Digenic cases involved a mix of genes, and most gene pairs were unique. People shared a core Parkinson's picture. Onset age and severity varied. PRKN cases started earlier and responded well to levodopa. No clear pattern by gene held across cases.

What it means for patients

The authors say compound heterozygous changes are a usual recessive cause. They say PRKN structural variants drive it. They say digenic cases were rare and mixed. They say the findings support testing for structural and sequence variants.

Why it is not certain yet

The evidence did not establish a digenic cause. The authors say proof needs more kinds of evidence. This includes segregation, function and replication. The review rests on published case reports. The abstract does not rate study quality. A review can only be as good as the studies in it.

Source

Compound heterozygous and digenic inheritance in early-onset Parkinson's disease: a systematic review.

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