Neuronal Ceroid Lipofuscinosis, PPT1-Related (Infantile NCL / CLN1 Disease)
Summary
PPT1-related NCL (CLN1 disease) is a lysosomal storage disorder caused by deficiency of the enzyme palmitoyl-protein thioesterase 1, which removes fatty acid chains from proteins in lysosomes. Without this enzyme, lipid-modified proteins accumulate in neurons, causing progressive neurodegeneration.
Practical takeaway
Particularly relevant if your partner is Finnish. A carrier test can determine partner status. Realised does not calculate reproductive risk or advise on reproductive decisions.
Evidence detail
What Carrier Status Means For You
You are not affected. One working copy of PPT1 is sufficient. Standard 25/50/25 recessive inheritance applies.
Population Context
The R122W variant is a Finnish founder mutation giving a carrier frequency of ~1 in 70 in Finland. PPT1-NCL is part of the Finnish disease heritage. Cases occur worldwide due to other PPT1 variants, but at much lower frequencies.
Limitations
23andMe tests 3 PPT1 variants. Coverage includes the Finnish founder and two others. NCL involves 13+ genes — this covers only CLN1.