Primary Hyperoxaluria Type 2 (PH2)

Summary

Primary hyperoxaluria type 2 is a metabolic condition where deficiency of the GRHPR enzyme leads to overproduction of oxalate, which is excreted through the kidneys. Oxalate combines with calcium to form calcium oxalate crystals — the main component of kidney stones. Progressive crystal deposition damages the kidneys.

Practical takeaway

Given the rarity, partner carrier risk is very low unless consanguinity is present. Carrier testing is available if desired. 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 GRHPR is sufficient. Standard 25/50/25 recessive inheritance applies.

Population Context

PH2 is rare across all populations, accounting for approximately 10% of all primary hyperoxaluria cases. No dramatic population-specific enrichment has been identified.

Limitations

23andMe tests 1 GRHPR variant. Coverage is minimal. Comprehensive testing recommended if clinically indicated.

Sources (3)

• ClinVar: GRHPR pathogenic/likely pathogenic variant database↗
• OMIM: #260000 (Hyperoxaluria, Primary, Type II)↗
• Cramer et al. (1999), "Mutations in GRHPR cause primary hyperoxaluria type II" — Nature Genetics↗