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Pediatric Nephrology (Berlin, Germany) Mar 2023Accurate diagnosis of primary hyperoxaluria (PH) has important therapeutic consequences. Since biochemical assessment can be unreliable, genetic testing is a crucial... (Review)
Review
Accurate diagnosis of primary hyperoxaluria (PH) has important therapeutic consequences. Since biochemical assessment can be unreliable, genetic testing is a crucial diagnostic tool for patients with PH to define the disease type. Patients with PH type 1 (PH1) have a worse prognosis than those with other PH types, despite the same extent of oxalate excretion. The relation between genotype and clinical phenotype in PH1 is extremely heterogeneous with respect to age of first symptoms and development of kidney failure. Some mutations are significantly linked to pyridoxine-sensitivity in PH1, such as homozygosity for p.G170R and p.F152I combined with a common polymorphism. Although patients with these mutations display on average better outcomes, they may also present with CKD stage 5 in infancy. In vitro studies suggest pyridoxine-sensitivity for some other mutations, but confirmatory clinical data are lacking (p.G47R, p.G161R, p.I56N/major allele) or scarce (p.I244T). These studies also suggest that other vitamin B6 derivatives than pyridoxine may be more effective and should be a focus for clinical testing. PH patients displaying the same mutation, even within one family, may have completely different clinical outcomes. This discordance may be caused by environmental or genetic factors that are unrelated to the effect of the causative mutation(s). No relation between genotype and clinical or biochemical phenotypes have been found so far in PH types 2 and 3. This manuscript reviews the current knowledge on the genetic background of the three types of primary hyperoxaluria and its impact on clinical management, including prenatal diagnosis.
Topics: Humans; Hyperoxaluria, Primary; Pyridoxine; Mutation; Genetic Testing; Genotype; Transaminases
PubMed: 35695965
DOI: 10.1007/s00467-022-05613-2 -
Journal of Medical Case Reports Oct 2023Primary hyperoxaluria (PH) is a rare genetic disorder characterized by the excessive production and accumulation of oxalate. We present five cases of PH, each exhibiting...
BACKGROUND
Primary hyperoxaluria (PH) is a rare genetic disorder characterized by the excessive production and accumulation of oxalate. We present five cases of PH, each exhibiting varying manifestations of the disorder including a case presenting as postpartum kidney failure. Notably, three of these cases involve a previously unreported mutation.
CASE PRESENTATIONS
We evaluated five Indian patients who presented with varying manifestations of PH. The first case, a 30 year old woman, presented as post-partum kidney failure and was found to be having oxalate nephropathy precipitated by dietary oxalate overload in the setting of previously undiagnosed PH. Genetic analysis revealed a previously unreported mutation in the alanine-glyoxylate aminotransferase gene. The patient underwent simultaneous kidney liver transplant. The second and third cases, 26 and 28 year old women respectively, were asymptomatic siblings of the first patient, who were diagnosed through screening. The fourth case is a 12 year boy with PH type 1 presenting as nephrolithiasis and rapidly worsening kidney function requiring combined kidney liver kidney transplant. Case 5 is a 6 year old male child with type 2 PH presenting with nephrolithiasis, nephrocalcinosis and normal kidney function. All the patients were born to consanguineous parents.
CONCLUSIONS
Due to limited clinical suspicion and inadequate diagnostic resources in certain countries with limited resources, it is possible for PH to go undiagnosed. The manifestations of the disease can range from no noticeable symptoms to severe disease. Interestingly, in some individuals with primary hyperoxaluria, the disease may not exhibit any symptoms until it is triggered by a high intake of dietary oxalate.
Topics: Male; Child; Humans; Female; Adult; Hyperoxaluria, Primary; Kidney; Oxalates; Kidney Calculi; Renal Insufficiency
PubMed: 37803380
DOI: 10.1186/s13256-023-04129-z -
Kidney International Reports Feb 2022
PubMed: 35155853
DOI: 10.1016/j.ekir.2021.12.032 -
Frontiers in Genetics 2023Primary hyperoxaluria (PH) is a rare genetic disorder characterized by excessive accumulation of oxalate in plasma and urine, resulting in various phenotypes due to...
Primary hyperoxaluria (PH) is a rare genetic disorder characterized by excessive accumulation of oxalate in plasma and urine, resulting in various phenotypes due to allelic and clinical heterogeneity. This study aimed to analyze the genotype of 21 Chinese patients with primary hyperoxaluria (PH) and explore their correlations between genotype and phenotype. Combined with clinical phenotypic and genetic analysis, we identified 21 PH patients from highly suspected Chinese patients. The clinical, biochemical, and genetic data of the 21 patients were subsequently reviewed. We reported 21 cases of PH in China, including 12 cases of PH1, 3 cases of PH2 and 6 cases of PH3, and identified 2 novel variants (c.632T > G and c.823_824del) in gene and 2 novel variants (c.258_272del and c.866-34_866-8del) in gene, respectively. A possible PH3 hotspot variant c.769T > G was identified for the first time. In addition, patients with PH1 showed higher levels of creatinine and lower eGFR than those with PH2 and PH3. In PH1, patients with severe variants in both alleles had significantly higher creatinine and lower eGFR than other patients. Delayed diagnosis still existed in some late-onset patients. Of all cases, 6 had reached to end-stage kidney disease (ESKD) at diagnosis with systemic oxalosis. Five patients were on dialysis and three had undergone kidney or liver transplants. Notably, four patients showed a favorable therapeutic response to vitamin B6, and c.823_824dup and c.145A > C may be identified as potentially vitamin B6-sensitive genotypes. In brief, our study identified 4 novel variants and extended the variant spectrum of PH in the Chinese population. The clinical phenotype was characterized by large heterogeneity, which may be determined by genotype and a variety of other factors. We first reported two variants that may be sensitive to vitamin B6 therapy in Chinese population, providing valuable references for clinical treatment. In addition, early screening and prognosis of PH should be given more attention. We propose to establish a large-scale registration system for rare genetic diseases in China and call for more attention on rare kidney genetic diseases.
PubMed: 37139236
DOI: 10.3389/fgene.2023.1124745 -
The Journal of Vascular Access Nov 2023A 3-month-old male infant was admitted to our unit due to acute decompensation of chronic kidney disease of unknown etiology. Further investigation led to the diagnosis...
A 3-month-old male infant was admitted to our unit due to acute decompensation of chronic kidney disease of unknown etiology. Further investigation led to the diagnosis of primary hyperoxaluria type 1. As the patient did not recover, hemodialysis was initiated with a non-tunneled femoral catheter. A tunneled Hickman catheter was placed in the internal jugular vein. The patient experienced moderate intradialytic exit-site bleeding and catheter malfunction, which initially responded to pressure and postural changes. During the third session, the patient suffered cardiopulmonary arrest. After stabilization, a chest hematoma was identified. Fluoroscopy revealed a catheter breakage. Despite initial stabilization, the patient developed septic shock due to and died several days later. Hemodialysis is sometimes necessary in children under 24 months with chronic kidney disease. Vascular access is a major challenge in these patients due to lack of appropriate catheter sizes and high complication rates. Hemodialysis catheter fracture is an uncommon complication, and diagnosis can be difficult when the breakage involves the subcutaneous segment. Persistent intradialytic bleeding and mechanical malfunction should raise suspicion of this complication and should elicit catheter revision under fluoroscopy. Without prompt diagnosis, catheter breakage may have fatal consequences, as in our case.
Topics: Child; Infant; Humans; Male; Catheters, Indwelling; Renal Dialysis; Hematoma; Renal Insufficiency, Chronic; Central Venous Catheters; Jugular Veins; Catheterization, Central Venous
PubMed: 35394377
DOI: 10.1177/11297298221086854 -
Clinical Kidney Journal May 2022Primary hyperoxaluria type 1 (PH1) is a rare and severe autosomal recessive disease of oxalate metabolism, resulting from a mutation in the gene that encodes the... (Review)
Review
Primary hyperoxaluria type 1 (PH1) is a rare and severe autosomal recessive disease of oxalate metabolism, resulting from a mutation in the gene that encodes the hepatic peroxisomal enzyme alanine-glyoxylate aminotransferase (AGT). Until recently, treatment of PH1 was supportive, consisting of intensive hyperhydration, use of crystallization inhibitors (citrate and neutral phosphorus), in a subset of responsive PH1 patients' pharmacologic doses of vitamin B6 (pyridoxine), and kidney and liver transplantation when patients progressed to kidney failure. Treatment approaches have been similar for PH2 caused by mutations in hepatic glyoxylate reductase/hydroxypyruvate reductase (), although pyridoxine does not have any benefit in this group. PH3 is caused by mutations of mitochondrial 4-hydroxy-2-oxoglutarate aldolase () and was the most recently described. Kidney failure appears less common in PH3, although kidney stones occur as frequently as in PH1 and PH2. Oxalate metabolism in the liver is complex. Novel therapies based on RNA interference (RNAi) have recently emerged to modulate these pathways, designed to deplete substrate for enzymes upstream and decrease/avoid oxalate production. Two hepatic enzymes have been targeted to date in PH: glycolate oxidase (GO) with lumasiran and lactate dehydrogenase A (LDH-A) with nedosiran. Lumasiran was approved for the treatment of PH1 in 2020 by both the European Medicines Agency and the Food and Drug Administration, whilst clinical trials with nedosiran are ongoing. Results with the two RNAi therapies demonstrate a significant reduction of urinary oxalate excretion in PH1 patients, but long-term data on efficacy (preservation of kidney function, decreased stone events) and safety remain to be established. Nevertheless, the hepatically targeted RNAi approach represents a potential 'game changer' in the field of PH1, bringing hope to families and patients that they may be able to avoid liver and/or kidney transplantation in the future and suffer fewer stone events, perhaps with less strict therapeutic regimens. Pharmacological compounds directly inhibiting GO or LDH are also under development and could be of special interest in developing countries where RNAi therapies may not be readily available in the near future. Approaches to manipulate the intestinal microbiome with a goal to increase oxalate degradation or to stimulate secretion of oxalate into the intestine from plasma are also under development. Overall, we appear to be entering a new phase of PH treatment, with an array of promising approaches emerging that will need optimization and evaluation to establish long-term efficacy and safety.
PubMed: 35592618
DOI: 10.1093/ckj/sfab245 -
Nephrology, Dialysis, Transplantation :... Apr 2022Primary hyperoxaluria (PH) type 3 (PH3) is caused by mutations in the hydroxy-oxo-glutarate aldolase 1 gene. PH3 patients often present with recurrent urinary stone...
BACKGROUND
Primary hyperoxaluria (PH) type 3 (PH3) is caused by mutations in the hydroxy-oxo-glutarate aldolase 1 gene. PH3 patients often present with recurrent urinary stone disease in the first decade of life, but prior reports suggested PH3 may have a milder phenotype in adults. This study characterized clinical manifestations of PH3 across the decades of life in comparison with PH1 and PH2.
METHODS
Clinical information was obtained from the Rare Kidney Stone Consortium PH Registry (PH1, n = 384; PH2, n = 51; PH3, n = 62).
RESULTS
PH3 patients presented with symptoms at a median of 2.7 years old compared with PH1 (4.9 years) and PH2 (5.7 years) (P = 0.14). Nephrocalcinosis was present at diagnosis in 4 (7%) PH3 patients, while 55 (89%) had stones. Median urine oxalate excretion was lowest in PH3 patients compared with PH1 and PH2 (1.1 versus 1.6 and 1.5 mmol/day/1.73 m2, respectively, P < 0.001) while urine calcium was highest in PH3 (112 versus 51 and 98 mg/day/1.73 m2 in PH1 and PH2, respectively, P < 0.001). Stone events per decade of life were similar across the age span and the three PH types. At 40 years of age, 97% of PH3 patients had not progressed to end-stage kidney disease compared with 36% PH1 and 66% PH2 patients.
CONCLUSIONS
Patients with all forms of PH experience lifelong stone events, often beginning in childhood. Kidney failure is common in PH1 but rare in PH3. Longer-term follow-up of larger cohorts will be important for a more complete understanding of the PH3 phenotype.
Topics: Female; Humans; Hyperoxaluria; Hyperoxaluria, Primary; Male; Mutation; Nephrolithiasis; Phenotype; Renal Insufficiency
PubMed: 33543760
DOI: 10.1093/ndt/gfab027 -
Pharmacological Reviews Dec 2023Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and... (Review)
Review
Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and sensory organ systems, caused by irregular liver metabolism and production of functional factors. Examples of such diseases discussed in this article include primary hyperoxaluria, familial hypercholesterolemia, acute hepatic porphyria, hereditary transthyretin amyloidosis, hemophilia, atherosclerotic cardiovascular diseases, -1 antitrypsin deficiency-associated liver disease, and complement-mediated diseases. Nucleic acid therapeutics use nucleic acids and related compounds as therapeutic agents to alter gene expression for therapeutic purposes. The two most promising, fastest-growing classes of nucleic acid therapeutics are antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs). For each listed SDLO disease, this article discusses epidemiology, symptoms, genetic causes, current treatment options, and advantages and disadvantages of nucleic acid therapeutics by either ASO or siRNA drugs approved or under development. Furthermore, challenges and future perspectives on adverse drug reactions and toxicity of ASO and siRNA drugs for the treatment of SDLO diseases are also discussed. In summary, this review article will highlight the clinical advantages of nucleic acid therapeutics in targeting the liver for the treatment of SDLO diseases. SIGNIFICANCE STATEMENT: Systemic diseases of liver origin (SDLO) contain rare and common complex diseases caused by irregular functions of the liver. Nucleic acid therapeutics have shown promising clinical advantages to treat SDLO. This article aims to provide the most updated information on targeting the liver with antisense oligonucleotides and small interfering RNA drugs. The generated knowledge may stimulate further investigations in this growing field of new therapeutic entities for the treatment of SDLO, which currently have no or limited options for treatment.
Topics: Humans; Nucleic Acids; RNA, Small Interfering; Oligonucleotides, Antisense; Liver Diseases
PubMed: 37696583
DOI: 10.1124/pharmrev.123.000815 -
Patients with primary hyperoxaluria type 2 have significant morbidity and require careful follow-up.Kidney International Dec 2019Primary hyperoxaluria type 2 is a rare inherited disorder of glyoxylate metabolism causing nephrocalcinosis, renal stone formation and ultimately kidney failure....
Primary hyperoxaluria type 2 is a rare inherited disorder of glyoxylate metabolism causing nephrocalcinosis, renal stone formation and ultimately kidney failure. Previously, primary hyperoxaluria type 2 was considered to have a more favorable prognosis than primary hyperoxaluria type 1, but earlier reports are limited by low patient numbers and short follow up periods. Here we report on the clinical, genetic, and biochemical findings from the largest cohort of patients with primary hyperoxaluria type 2, obtained by a retrospective record review of genetically confirmed cases in the OxalEurope registry, a dataset containing 101 patients from eleven countries. Median follow up was 12.4 years. Median ages at first symptom and diagnosis for index cases were 3.2 years and 8.0 years, respectively. Urolithiasis was the most common presenting feature (82.8% of patients). Genetic analysis revealed 18 novel mutations in the GRHPR gene. Of 238 spot-urine analyses, 23 (9.7%) were within the normal range for oxalate as compared to less than 4% of 24-hour urine collections. Median intra-individual variation of 24-hour oxalate excretion was substantial (34.1%). At time of review, 12 patients were lost to follow-up; 45 of the remaining 89 patients experienced chronic kidney disease stage 2 or greater and 22 patients had reached stage 5. Median renal survival was 43.3 years, including 15 kidney transplantations in 11 patients (1 combined with liver transplantation). Renal outcome did not correlate with genotype, biochemical parameters or initially present nephrocalcinosis. Thus, primary hyperoxaluria type 2 is a disease with significant morbidity. Accurate diagnosis by 24-hour urine analysis and genetic testing are required with careful follow-up.
Topics: Adolescent; Adult; Age of Onset; Child; Child, Preschool; Europe; Female; Humans; Hyperoxaluria, Primary; Infant; Kidney Failure, Chronic; Kidney Transplantation; Male; Registries; Retrospective Studies; Young Adult
PubMed: 31685312
DOI: 10.1016/j.kint.2019.08.018 -
Pediatric Nephrology (Berlin, Germany) Jan 2024Primary hyperoxaluria type 1 (PH1) is a rare, severe genetic disease causing increased hepatic oxalate production resulting in urinary stone disease, nephrocalcinosis,... (Observational Study)
Observational Study
BACKGROUND
Primary hyperoxaluria type 1 (PH1) is a rare, severe genetic disease causing increased hepatic oxalate production resulting in urinary stone disease, nephrocalcinosis, and often progressive chronic kidney disease. Little is known about the natural history of urine and plasma oxalate values over time in children with PH1.
METHODS
For this retrospective observational study, we analyzed data from genetically confirmed PH1 patients enrolled in the Rare Kidney Stone Consortium PH Registry between 2003 and 2018 who had at least 2 measurements before age 18 years of urine oxalate-to-creatinine ratio (Uox:cr), 24-h urine oxalate excretion normalized to body surface area (24-h Uox), or plasma oxalate concentration (Pox). We compared values among 3 groups: homozygous G170R, heterozygous G170R, and non-G170R AGXT variants both before and after initiating pyridoxine (B6).
RESULTS
Of 403 patients with PH1 in the registry, 83 met the inclusion criteria. Uox:cr decreased rapidly over the first 5 years of life. Both before and after B6 initiation, patients with non-G170R had the highest Uox:cr, 24-h Uox, and Pox. Patients with heterozygous G170R had similar Uox:cr to homozygous G170R prior to B6. Patients with homozygous G170R had the lowest 24-h Uox and Uox:cr after B6. Urinary oxalate excretion and Pox tend to decrease over time during childhood. eGFR over time was not different among groups.
CONCLUSIONS
Children with PH1 under 5 years old have relatively higher urinary oxalate excretion which may put them at greater risk for nephrocalcinosis and kidney failure than older PH1 patients. Those with homozygous G170R variants may have milder disease. A higher resolution version of the Graphical abstract is available as Supplementary information.
Topics: Humans; Child; Adolescent; Child, Preschool; Oxalates; Nephrocalcinosis; Hyperoxaluria, Primary; Kidney Calculi
PubMed: 37458799
DOI: 10.1007/s00467-023-06074-x