Neuronal Ceroid Lipofuscinosis, CLN5-Related (Finnish Variant Late Infantile NCL)

Summary

CLN5-related NCL is one of the neuronal ceroid lipofuscinoses — a group of progressive neurodegenerative conditions caused by accumulation of ceroid lipofuscin in neurons. The CLN5 protein is involved in lysosomal function, though its exact role is still being characterised.

Practical takeaway

Primarily relevant if your partner is Finnish. Carrier testing is available. 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 CLN5 is sufficient. Standard 25/50/25 recessive inheritance applies.

Population Context

Part of the Finnish disease heritage. The Y392X variant is almost exclusively Finnish, with a carrier frequency of ~1 in 50. CLN5-NCL accounts for the majority of NCL cases in Finland.

Limitations

23andMe tests 1 CLN5 variant. NCL can be caused by variants in 13+ genes. A negative CLN5 result does not rule out carrier status for other NCL forms.

Sources (3)

• ClinVar: CLN5 pathogenic/likely pathogenic variant database↗
• OMIM: #256731 (Ceroid Lipofuscinosis, Neuronal, 5)↗
• Savukoski et al. (1998), "CLN5, a novel gene encoding a putative transmembrane protein" — Nature Genetics↗