Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020500 (hyperoxaluria)
 912 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the case of a 78-year-old patient with late diagnosis of hyperoxaluria type III (PH3). He developed renal failure after nephrectomy for clear cell papillary renal carcinoma and complained of recurrent urolithiasis for some 30 years, whose aetiology was never identified. Biochemical laboratory investigations of urine and urolithiasis composition revealed marked hyperoxaluria but normal concentrations of urinary glyceric and glycolic acid as well as stones of idiopathic calcium-oxalate appearance. Furthermore, the dietary survey showed excessive consumption of food supplements containing massive amounts of oxalate precursors. However, the persistence of excessive hyperoxaluria after his eating habits was changed leading us to perform molecular genetic testing. We found heterozygous mutations of the recently PH3-associated HOGA1 gene when sequencing PH genes. This is the first description of late diagnosis primary PH3 in a patient with several additional pro-lithogenic factors. This case illustrates the importance of undertaking a complete biological work-up to determine the aetiology of hyperoxaluria. This may reveal underdiagnosed primary hyperoxaluria, even in older patients.
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PMID:Late diagnosis of primary hyperoxaluria type III. 2774 50

Oxalate (Ox) is an end-product of metabolism, important for poor solubility of its calcium salt in biological fluids. Ox can therefore be found in about 70% of urinary calculi. Hyperoxaluria (HOx) defined as Ox exceeding 0.5 mmol)/day, may cause nephrolithiasis/nephrocalcinosis and may be classified as dietary (DH), enteric (EH) or primary (PH). Fractional intestinal absorption of Ox is less than 10%, but increases to over 20% at calcium intakes below 200 mg/day. DH is often related to low-calcium diets. EH is caused by non-absorbed fatty acids which bind to calcium and lower its concentration in the intestinal lumen. Ox forms more soluble complexes with other cations and results in HOx. Similar mechanisms may cause HOx following bariatric surgery. PHs are the most severe causes of HOx. Three types have so far been described, all being autosomic recessive. PH1 is due to mutations of AGXT gene encoding liver alanine-glyoxylate aminotransferase, PH2 is caused by mutations of GR-HPR gene encoding glyoxylate reductase and PH3 by mutations of HOGA1 encoding for hydroxyl-oxoglutarate aldolase. HOx results from deficient detoxification from glyoxylate, which is oxidized to Ox. The three PHs have different severity, though not always clinically distinguishable. They are identified through genetics and, in PH1, good genotype/phenotype correlations have been established. Thanks to early biochemical and genetic diagnosis, which are crucial to either prevent progression to ESRF or choose adequate transplantation strategies, the outlook of PH patients has dramatically improved in the last decades and will furtherly do in view of new therapeutic strategies.
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PMID:[The Hyperoxalurias]. 2796 20

Primary hyperoxalurias (PH) are devastating, autosomal recessive diseases causing renal stones. Undifferentiated hyperoxaluria is seen in up to 43% of Pakistani paediatric stone patients. High rates of consanguinity in Pakistan suggest significant local prevalence. There is no detailed information regarding number of cases, clinical features, and genetics in Pakistan-origin (P-o) patients. We reviewed available information on P-o PH patients recorded in the literature as well as from two major PH registries (the Rare Kidney Stone Consortium PH Registry (RKSCPHR) and the OxalEurope PH Registry (OxER); and the Aga Khan University Hospital in Pakistan. After excluding overlaps, we noted 217 P-o PH subjects (42 in OxER and 4 in RKSCPHR). Presentations were protean. Details of mutations were available for 94 patients of 201 who had genetic analyses. Unique mutations were noted. Mutation [c.508G>A (p. Gly170Arg)] (present in up to 25% in the West) was reported in only one case. In one series, only 30% had mutations on exons 1,4,7 of AGXT. Of 42 P-o patients in OxER, 52.4% were PH1, 45.2% PH2, and 2.4% PH3. Of concern is that diagnosis was made after renal transplant rejection (four cases) and on bone-marrow aspiration (in five). Lack of consideration of PH as a diagnosis, late diagnosis, and loss of transplanted kidneys mandates that PH be searched for diligently. Mutation analysis will need to extend to all exons and include PH 1,2,3. There is a need to spread awareness and identify patients through a scoring or screening system that alerts physicians to consider a diagnosis of PH.
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PMID:Primary hyperoxaluria in populations of Pakistan origin: results from a literature review and two major registries. 2866 Feb 84

The major clinical manifestation of the Primary Hyperoxalurias (PH) is increased production of oxalate, as a consequence of genetic mutations that lead to aberrant glyoxylate and hydroxyproline metabolism. Hyperoxaluria can lead to the formation of calcium-oxalate kidney stones, nephrocalcinosis and renal failure. Current therapeutic approaches rely on organ transplants and more recently modifying the pathway of oxalate synthesis using siRNA therapy. We have recently reported that the metabolism of trans-4-hydroxy-L-proline (Hyp), an amino acid derived predominantly from collagen metabolism, is a significant source of oxalate production in individuals with PH2 and PH3. Thus, the first enzyme in the Hyp degradation pathway, hydroxyproline dehydrogenase (HYPDH), represents a promising therapeutic target for reducing endogenous oxalate production in these individuals. This is supported by the observation that individuals with inherited mutations in HYPDH (PRODH2 gene) have no pathological consequences. The creation of mouse models that do not express HYPDH will facilitate research evaluating HYPDH as a target. We describe the phenotype of the Prodh2 knock out mouse model and show that the lack of HYPDH in PH mouse models results in lower levels of urinary oxalate excretion, consistent with our previous metabolic tracer and siRNA-based knockdown studies. The double knockout mouse, Grhpr KO (PH2 model) and Prodh2 KO, prevented calcium-oxalate crystal deposition in the kidney, when placed on a 1% Hyp diet. These observations support the use of the Grhpr KO mice to screen HYPDH inhibitors in vivo. Altogether these data support HYPDH as an attractive therapeutic target for PH2 and PH3 patients.
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PMID:The effects of the inactivation of Hydroxyproline dehydrogenase on urinary oxalate and glycolate excretion in mouse models of primary hyperoxaluria. 3207 46