[The Hyperoxalurias].

Area of Science:

• Nephrology
• Metabolic Disorders
• Genetics

Background:

• Oxalate (Ox) is a metabolic end-product poorly soluble as calcium oxalate, contributing to ~70% of urinary calculi.
• Hyperoxaluria (HOx) is defined as urinary oxalate exceeding 0.5 mmol/day, potentially causing nephrolithiasis and nephrocalcinosis.
• HOx classifications include dietary (DH), enteric (EH), and primary (PH), each with distinct underlying mechanisms.

Purpose of the Study:

• To review the causes, classifications, and diagnostic approaches to hyperoxaluria.
• To highlight the importance of early diagnosis and emerging therapeutic strategies for primary hyperoxalurias.

Main Methods:

• Literature review of oxalate metabolism, hyperoxaluria classifications, and genetic causes.
• Discussion of fractional intestinal absorption of oxalate and factors influencing it.
• Overview of diagnostic methods including biochemical and genetic testing.

Main Results:

• Dietary HOx is linked to low-calcium diets; enteric HOx results from non-absorbed fatty acids binding calcium.
• Primary Hyperoxalurias (PH1, PH2, PH3) are severe, autosomal recessive disorders caused by specific gene mutations affecting glyoxylate detoxification.
• Genotype-phenotype correlations are established for PH1, aiding in diagnosis and management.

Conclusions:

• Early biochemical and genetic diagnosis of HOx is critical for preventing end-stage renal failure (ESRF) and guiding transplantation strategies.
• Advances in diagnosis and new therapeutic approaches are significantly improving the prognosis for PH patients.
• Understanding the diverse causes of HOx is essential for effective patient management and improved long-term outcomes.