BACKGROUND: Maturity onset diabetes of the young (MODY) is the most commonly reported form of monogenic diabetes in the pediatric population. Only a few cases of digenic MODY have been reported up to now. CASE REPORT: A female patient was diagnosed with diabetes at the age of 7 years and was treated with insulin. A strong family history of diabetes was present in the maternal side of the family. The patient also presented hypomagnesemia, glomerulocystic kidney disease and a bicornuate uterus. Genetic testing of the patient revealed that she was a double heterozygous carrier of HNF1A gene variant c.685C > T; (p.Arg229Ter) and a whole gene deletion of the HNF1B gene. Her mother was a carrier of the same HNF1A variant. CONCLUSION: Digenic inheritance of MODY pathogenic variants is probably more common than currently reported in literature. The use of Next Generation Sequencing panels in testing strategies for MODY could unmask such cases that would otherwise remain undiagnosed.

• Klíčová slova
• Digenic MODY, HNF1A-MODY, HNF1B-MODY, MODY 3, MODY 5,
• MeSH
• cystická onemocnění ledvin genetika   patologie   MeSH
• diabetes mellitus 2. typu genetika   patologie   MeSH
• dítě MeSH
• fenotyp MeSH
• hepatocytární jaderný faktor 1-alfa genetika   MeSH
• hepatocytární jaderný faktor 1-beta genetika   MeSH
• heterozygot MeSH
• lidé MeSH
• mutace MeSH
• nemoci ledvin genetika   patologie   MeSH
• uterus abnormality   MeSH
• vrozené poruchy tubulárního transportu genetika   patologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• hepatocytární jaderný faktor 1-alfa MeSH
• hepatocytární jaderný faktor 1-beta MeSH
• HNF1A protein, human MeSH Prohlížeč
• HNF1B protein, human MeSH Prohlížeč

• Klíčová slova
• Excretion fraction of uric acid *, Hypouricemia *, SLC22A12 *, URAT1 *, Urate transport *,
• MeSH
• akutní poškození ledvin krev   prevence a kontrola   moč   MeSH
• alopurinol aplikace a dávkování   MeSH
• antioxidancia aplikace a dávkování   MeSH
• cystinóza krev   diagnóza   moč   MeSH
• diferenciální diagnóza MeSH
• dítě MeSH
• Fanconiho syndrom krev   diagnóza   moč   MeSH
• genetické testování MeSH
• kyselina močová krev   metabolismus   moč   MeSH
• ledvinové kanálky metabolismus   MeSH
• lidé MeSH
• močové kameny krev   diagnóza   genetika   moč   MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• proteiny usnadňující transport glukosy genetika   MeSH
• renální reabsorpce MeSH
• syndrom nepřiměřené sekrece ADH krev   diagnóza   moč   MeSH
• vrozené poruchy tubulárního transportu krev   diagnóza   genetika   moč   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• alopurinol MeSH
• antioxidancia MeSH
• kyselina močová MeSH
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• proteiny usnadňující transport glukosy MeSH
• SLC22A12 protein, human MeSH Prohlížeč
• SLC2A9 protein, human MeSH Prohlížeč

BACKGROUND: Renal hypouricemia is a rare heterogeneous inherited disorder characterized by impaired tubular uric acid transport, reabsorption insufficiency and /or acceleration of secretion. The affected individuals are predisposed to nephrolithiasis and recurrent episodes of exercise-induced acute kidney injury. Type 1 is caused by dysfunctional variants in the SLC22A12 gene (URAT1), while type 2 is caused by defects in the SLC2A9 gene (GLUT9). To date, more than 150 patients with the loss-of-function mutations for the SLC22A12 gene have been found (compound heterozygotes and/or homozygotes), most of whom are Japanese and Koreans. CASE PRESENTATION: Herein, we report a nine year old Sri Lankan boy with renal hypouricemia (serum uric acid 97 μmol/L, fractional excretion of uric acid 33%).The sequencing analysis of SLC22A12 revealed a potentially deleterious missense variant c.1400C > T (p.T467 M, rs200104135) in heterozygous state. This variant has been previously identified in homozygous and/or compound heterozygous state with other causative SLC22A12 variant c.1245_1253del (p.L415_G417del) in Roma population. CONCLUSIONS: This is the first identification of a family with mild renal hypouricemia1 associated to the p.T467 M variant. Detailed investigations of urate blood and urine concentrations in patients with unexplained hypouricemia are needed and renal hypouricemia should also be considered in patients other than those from Japan and/or Korea. Our finding confirms an uneven geographical and ethnic distribution of Romany prevalent SLC22A12 variant that need to be considered in Asian patients (population data Genome Aggregation Database: allele frequency in South Asia 0.007055, in East Asia 0.001330).

• Klíčová slova
• Renal hypouricemia, SLC22A12, URAT1, Uric acid transporters,
• MeSH
• dítě MeSH
• dospělí MeSH
• heterozygot * MeSH
• lidé MeSH
• missense mutace * MeSH
• mladiství MeSH
• močové kameny genetika   MeSH
• předškolní dítě MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• vrozené poruchy tubulárního transportu genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Srí Lanka MeSH
• Názvy látek
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• SLC22A12 protein, human MeSH Prohlížeč

BACKGROUND: Renal hypouricemia (RHUC), a rare inherited disorder characterized by impaired uric acid (UA) reabsorption in the proximal tubule, is caused by mutations in SLC22A12 or SLC2A9. Most mutations have been identified in Japanese patients, and only a few have been detected in Europeans. METHODS: We report clinical, biochemical and genetics findings of fourteen Spanish patients, six Caucasians and eight of Roma ethnia, diagnosed with idiopathic RHUC. Two of the patients presented exercise-induced acute renal failure and another one had several episodes of nephrolithiasis and four of them had progressive deterioration of renal function, while the rest were asymptomatic. RESULTS: Molecular analysis revealed SLC22A12 mutations in ten of the patients, and SLC2A9 mutations in the other four. A new heterozygous SLC22A12 missense mutation, c.1427C>A (p.A476D), was identified in two affected members of the same family. The rest of the patients presented homozygous, heterozygous or compound heterozygous mutations that have been previously identified in patients with RHUC; SLC22A12 p.T467M and p.L415_G417del, and SLC2A9 p.T125M. Expression studies in Xenopus oocytes revealed that c.1427C>A reduced UA transport but did not alter the location of URAT1 protein on the plasma membrane. CONCLUSIONS: The biochemical and clinical features of our patients together with the genetic analysis results confirmed the diagnosis of RHUC. This is the first report describing SLC22A12 and SLC2A9 mutations in Spanish patients.

• Klíčová slova
• Chronic kidney disease, Exercise-induced acute renal failure, GLUT9, Mutation, Renal hypouricemia, SLC22A12, SLC2A9, URAT1, Uric acid transporters,
• MeSH
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• močové kameny genetika   MeSH
• mutace * MeSH
• předškolní dítě MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• proteiny usnadňující transport glukosy genetika   MeSH
• rodokmen MeSH
• senioři MeSH
• vrozené poruchy tubulárního transportu genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Španělsko MeSH
• Názvy látek
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• proteiny usnadňující transport glukosy MeSH
• SLC22A12 protein, human MeSH Prohlížeč
• SLC2A9 protein, human MeSH Prohlížeč

The Roma represents a transnational ethnic group, with a current European population of 8-10 million. The evolutionary process that had the greatest impact on the gene pool of the Roma population is called the founder effect. Renal hypouricemia (RHUC) is a rare heterogenous inherited disorder characterized by impaired renal urate reabsorption. The affected individuals are predisposed to recurrent episodes of exercise-induced nonmyoglobinuric acute kidney injury and nephrolithiasis. To date, more than 150 patients with a loss-of-function mutation for the SLC22A12 (URAT1) gene have been found, most of whom are Asians. However, RHUC 1 patients have been described in a variety of ethnic groups (e.g., Arab Israelis, Iraqi Jews, Caucasians, and Roma) and in geographically noncontiguous countries. This study confirms our previous findings regarding the high frequency of SLC22A12 variants observed. Frequencies of the c.1245_1253del and c.1400C>T variants were found to be 1.92% and 5.56%, respectively, in a subgroup of the Roma population from five regions in three countries: Slovakia, Czech Republic, and Spain. Our findings suggested that the common dysfunction allelic variants of URAT1 exist in the general Roma population and thus renal hypouricemia should be kept in differential diagnostic algorithm on Roma patients with defect in renal tubular urate transport. This leads to confirm that the genetic drift in the Roma have increased the prevalence of hereditary disorders caused by very rare variants in major population.

• Klíčová slova
• Roma population, SLC22A12, URAT1, prevalent variants, renal hypouricemia,
• MeSH
• efekt zakladatele MeSH
• frekvence genu MeSH
• genetické asociační studie MeSH
• heterozygot MeSH
• lidé MeSH
• močové kameny epidemiologie   genetika   MeSH
• molekulární evoluce MeSH
• přenašeče organických aniontů genetika   MeSH
• prevalence MeSH
• proteiny přenášející organické kationty genetika   MeSH
• Romové genetika   MeSH
• sekvenční delece MeSH
• vrozené poruchy tubulárního transportu epidemiologie   genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• SLC22A12 protein, human MeSH Prohlížeč

BACKGROUND: Renal hypouricemia is a rare heterogeneous inherited disorder characterized by impaired tubular uric acid transport with severe complications, such as acute kidney injury and nephrolithiasis. Type 1 is caused by a loss-of-function mutation in the SLC22A12 gene (URAT1), while type 2 is caused by defects in the SLC2A9 gene (GLUT9). METHODS AND RESULTS: In this article we present clinical, biochemical and molecular genetics of two Czech patients. The serum uric acid in the probands was 57 and 98 µmol/l and expressed as an increase in the fractional excretion of uric acid (40 and 18 %). The sequencing analysis of SLC22A12 and SLC2A9 revealed novel variants p.R92C and p.R203C in URAT1 and p.G72D in GLUT9. Functional studies were performed for these novel variants and for previously reported variants p.I118HfsX27, p.G216R and p.N333S in GLUT9 responsible for renal hypouricemia in three probands from Czech Republic and United Kingdom. Functional studies showed significantly decreased urate uptake for all variants. However, urate uptake of GLUT9 variants prepared for both isoforms were not significantly different. CONCLUSIONS: This is the first complex function characterization of non-synonymous allelic variants in patients with renal hypouricemia regarding both GLUT9 isoforms. Our finding of defects in the SLC2A9 and SLC22A12 genes show the following: renal hypouricemia is not restricted to East Asia populations; urate uptake of GLUT9 variants prepared for both isoforms were not significantly different; renal hypouricemia type 2 has more wide clinical variability than type 1; the phenotypic severity of renal hypouricemia is not correlated with results of functional characterizations of URAT1 and GLUT9 variants.

• Klíčová slova
• GLUT9, Renal hypouricemia, SLC22A12, SLC2A9, URAT1, Uric acid transporters,
• MeSH
• dítě MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• močové kameny genetika   MeSH
• mutační analýza DNA MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• proteiny usnadňující transport glukosy genetika   MeSH
• vrozené poruchy tubulárního transportu genetika   MeSH
• Xenopus MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• proteiny usnadňující transport glukosy MeSH
• SLC22A12 protein, human MeSH Prohlížeč
• SLC2A9 protein, human MeSH Prohlížeč

BACKGROUND: Renal hypouricemia (RHUC) is a heterogeneous inherited disorder characterized by impaired tubular uric acid (UA) transport with severe complications, such as acute kidney injury. Type 1 is caused by a mutation in the SLC22A12 gene (URAT1) and type 2 in the SLC2A9 gene (GLUT9). In this article, the authors present a coexpression functional characterization of variants responsible for RHUC type 1 in a Czech family with polycystic kidney disease (PKD). METHODS: The serum UA concentration in the proband was 1.1 mg/dL and was expressed as an increase in the fractional excretion of UA (43%). The URAT1 allelic variants were prepared and their urate uptake and subcellular localization were studied by Xenopus oocytes expression system. Linkage analysis using a panel of 4 CA-repeat flanking markers for chromosome 16 and a panel of 3 CA-repeat flanking markers for chromosome 4 was performed, which carry the PKD1 and PKD2 genes, respectively. RESULTS: Coexpression results showed that p.G366R and p.R477H suppressed urate transport by wild types. Colocalization studies showed an accumulation of URAT1 in the endoplasmic reticulum of the p.G366R variant and mainly retention of wild-type protein by variants p.G366R and p.R477H. CONCLUSIONS: The findings suggest that not only loss-of-function mutation of URAT1 but also the dominant-negative effect cause RHUC through loss of UA absorption, partly due to protein misfolding caused by accumulation of URAT1 protein in the endoplasmic reticulum.

• MeSH
• alely MeSH
• dospělí MeSH
• genetická vazba MeSH
• heterozygot MeSH
• kyselina močová krev   MeSH
• lidé MeSH
• močové kameny komplikace   genetika   MeSH
• mutace MeSH
• mutační analýza DNA MeSH
• oocyty MeSH
• polycystické ledviny autozomálně dominantní komplikace   genetika   MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• proteiny usnadňující transport glukosy genetika   MeSH
• regulace genové exprese MeSH
• sbalování proteinů MeSH
• senioři MeSH
• stanovení celkové genové exprese MeSH
• vrozené poruchy tubulárního transportu komplikace   genetika   MeSH
• Xenopus laevis MeSH
• zdraví rodiny MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• kyselina močová MeSH
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• proteiny usnadňující transport glukosy MeSH
• SLC22A12 protein, human MeSH Prohlížeč
• SLC2A9 protein, human MeSH Prohlížeč

Renal hypouricemia is a rare heterogeneous inherited disorder characterized by impaired tubular uric acid transport with severe complications, such as acute kidney injury. Type 1 and 2 are caused by loss-of-function mutations in the SLC22A12 and SLC2A9 gene, respectively. A cohort of 881 randomly chosen ethnic Roma from two regions in Eastern Slovakia and two regions in the Czech Republic participated. Genomic DNA was isolated from buccal swabs and/or from blood samples. The c.1245_1253del and c.1400C>T genotypes were determined using polymerase chain reaction with allele-specific primers in a multiplex arrangement and/or direct sequencing of exon 7 and 9. Allele frequencies and genotypes were tested for Hardy-Weinberg equilibrium using the Chi-square test. 25 subjects were heterozygous and three were homozygous for the c.1245_1253del, while 92 subjects were heterozygous and two were homozygous for the c.1400C>T. Moreover, two participants were compound heterozygotes. Frequencies of the c.1245_1253del and c.1400C>T variants were 1.87 and 5.56 %, respectively. Our finding confirms an uneven geographical and ethnic distribution of SLC22A12 mutant variants. We found that the c.1245_1253del and c.1400C>T variants were present in the Czech and Slovak Roma population at unexpectedly high frequencies. Renal hypouricemia should be kept in mind during differential diagnostic on Roma patients with low serum uric acid concentrations.

• Klíčová slova
• Acute kidney injury, Renal hypouricemia, SLC22A12, URAT1,
• MeSH
• genetické testování metody   MeSH
• lidé MeSH
• močové kameny genetika   MeSH
• polymerázová řetězová reakce metody   MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• retrospektivní studie MeSH
• Romové genetika   MeSH
• vrozené poruchy tubulárního transportu genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Slovenská republika MeSH
• Názvy látek
• přenašeče organických aniontů MeSH
• proteiny přenášející organické kationty MeSH
• SLC22A12 protein, human MeSH Prohlížeč

Hypouricemia is defined as a serum urate levels less than 2 mg/dL (119 µmol/L). Primary hypouricemia is caused by disorders of purine metabolism and transport. This laboratory finding is sometimes overlooked and, following two genetic defects, should be considered in differential diagnosis of unexplained hypouricemia. Hereditary xanthinuria is autosomal recessive and due to mutations in xanthine oxidase, leading to over-production of xanthine and minimal production of urate. Patients have very low serum urate levels and suffer from elevated levels of xanthine in the urine, leading to xanthine stones, haematuria, and sometimes occult chronic kidney failure. Hypouricemia is the key to diagnosis. Hereditary renal hypouricemia is a new genetic defect of renal transport of uric acid. Two types were distinguished: a) renal hypouricemia type 1, caused by the defects in the SLC22A12 gene coding the human urate transporter 1 (hURAT1) and b) renal hypouricemia type 2, caused by the defects in the SLC2A9 gene, which encodes GLUT9 transporter. This disorder predisposes patients to exercise-induced acute renal failure and/or nephrolithiasis. Diagnosis is based on two markers: hypouricemia (<119 µmol/L) and increased fractional excretion of uric acid (>10%). Over one hundred cases were identified in Japan and and this number is unique worldwide. Several patients were described in Macedonia. We were able to detect four Czech families with hereditary xanthinuria and eight cases of hereditary renal hypouricemia. In conclusion, hereditary xanthinuria and hereditary renal hypouricemia are still unrecognized conditions. Patients with unexplained hypouricemia need detailed purine metabolic investigations.

• MeSH
• dítě MeSH
• dospělí MeSH
• genetická predispozice k nemoci * MeSH
• kyselina močová metabolismus   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• močové kameny genetika   metabolismus   MeSH
• poruchy metabolismu purinů a pyrimidinů genetika   metabolismus   MeSH
• puriny metabolismus   MeSH
• vrozené poruchy tubulárního transportu genetika   metabolismus   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyselina močová MeSH
• purine MeSH Prohlížeč
• puriny MeSH

• MeSH
• akutní poškození ledvin krev   diagnóza   etiologie   prevence a kontrola   MeSH
• alopurinol aplikace a dávkování   terapeutické užití   MeSH
• antiuratika aplikace a dávkování   terapeutické užití   MeSH
• biologické markery krev   MeSH
• lidé MeSH
• mladiství MeSH
• močové kameny krev   farmakoterapie   genetika   MeSH
• rozvrh dávkování léků MeSH
• sekundární prevence MeSH
• sportovní úrazy diagnóza   prevence a kontrola   MeSH
• vrozené poruchy tubulárního transportu krev   farmakoterapie   genetika   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• dopisy MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alopurinol MeSH
• antiuratika MeSH
• biologické markery MeSH