Clinical features of pediatric renal glucosuria cases due to SLC5A2 gene variants.

BACKGROUND: Familial renal glycosuria (FRG) is a rare renal tubular disorder characterized by a variable loss of glucose in the urine despite normal blood glucose levels, which is seen in a condition in which other tubular functions are preserved. In this study, the molecular and clinical characteristics of pediatric FRG cases due to SLC5A2 gene variants were defined. METHODS: Demographic features, diagnostic tests, and molecular analyses of patients with a diagnosis of FRG cases due to SLC5A2 gene variants were retrospectively analyzed between 2016 and 2019. RESULTS: The data of 16 patients who were clinically and genetically diagnosed with FRG in a 4-year period were analyzed. Seven (44%) of the cases were female and 9 (56%) were male. The median age at diagnosis was 6 years old (2 months old to 17 years old). Neuromotor development was found to be appropriate for the age in each case. Systemic blood pressure was evaluated as normal. A homozygous pathogenic variant in the SLC5A2 gene was detected in 14 patients in the genetic examination. A heterozygous variant was detected in one patient. In the other patient, two different heterozygous pathological variants were found in the SLC5A2 gene. CONCLUSIONS: It was revealed that growth and development were normal in children with glucosuria due to variations in the SCL5A2 gene. Renal function tests and urinary amino acid excretion were also within normal values. In our case series, the most common genetic variation in the SCL5A2 gene was the A219T (c.655G>A) variant.

Persistently high urine glucose levels caused by familial renal glycosuria.

Glycosuria generally occurs when the threshold for glucose reabsorption by the proximal renal tubule is exceeded or when reabsorption of filtered glucose is impaired. Although the discovery of glycosuria in a child will prompt screening for diabetes mellitus, it is also a sign of a rare tubulopathy called "familial renal glycosuria" (OMIM #233100). This tubulopathy is linked to a defect in the sodium-glucose co-transporter 2, encoded by the SLC5A2 gene. Here, we describe and discuss two pediatric cases in whom familial renal glycosuria was discovered fortuitously after the observation of persistently high urine glucose levels in the absence of hyperglycemia.

Renal glucosuria is associated with lower body weight and lower rates of elevated systolic blood pressure: results of a nationwide cross-sectional study of 2.5 million adolescents.

BACKGROUND: Gene coding mutations found in sodium glucose co-transporters (SGLTs) are known to cause renal glucosuria. SGLT2 inhibitors have recently been shown to be effective hypoglycemic agents as well as possessing cardiovascular and renal protective properties. These beneficial effects have to some extent, been attributed to weight loss and reduced blood pressure. The aim of the current study was to evaluate the prevalence of renal glucosuria amongst a large cohort of Israeli adolescents and to investigate whether renal glucosuria is associated with lower body weight and lower blood pressure values. METHODS: Medical and socio-demographic data were collected from the Israeli Defense Force's conscription center's database. A cross-sectional study to evaluate the association between conscripts diagnosed as overweight [BMI percentiles of ≥ 85 and < 95 and obesity (≥ 95 BMI percentile)] and afflicted with renal glucosuria was conducted. In addition, we assessed the association of renal glucosuria with elevated diastolic and systolic blood pressure. Multinomial regression models were used. RESULTS: The final study cohort comprised 2,506,830 conscripts of whom 1108 (0.044%) were diagnosed with renal glucosuria, unrelated to diabetes mellitus, with males twice as affected compared to females. The adjusted odds ratio for overweight and obesity was 0.66 (95% CI 0.50-0.87) and 0.62 (95% CI 0.43-0.88), respectively. Adolescents afflicted with renal glucosuria were also less likely to have an elevated systolic blood pressure of 130-139 mmHg with an adjusted odds ratio of 0.74 (95% CI 0.60-0.90). CONCLUSIONS: Renal glucosuria is associated with lower body weight and obesity as well as with lower rates of elevated systolic blood pressure.

A novel compound heterozygous mutation in SLC5A2 contributes to familial renal glucosuria in a Chinese family, and a review of the relevant literature.

Familial renal glucosuria (FRG) is a rare condition that involves isolated glucosuria despite normal blood glucose levels. Mutations in the solute carrier family 5 member 2 (SLC5A2) gene, which encodes sodium­glucose cotransporter 2 (SGLT2), have been reported to be responsible for the disease. Genetic testing of the SLC5A2 gene was conducted in a Chinese family with FRG. A number of online tools were used to predict the potential effect of the identified mutations on SGLT2 function. Additionally, the SLC5A2 mutations previously reported in PubMed were summarized. A novel compound heterozygous mutation (c.514T>C, p.W172R; c.1540C>T, p.P514S) of the SLC5A2 gene in a Chinese child with FRG was identified. In total, 86 mutations of the SLC5A2 gene have been reported to be associated with FRG. The novel compound heterozygous mutation (c.514T>C, p.W172R; c.1540C>T, p.P514S) of the SLC5A2 gene may be responsible for the onset of FRG. The present study provides a starting point for further investigation of the molecular pathogenesis of the SLC5A2 gene mutation in patients with FRG.

Renal glucosuria in schoolchildren: Clinical characteristics.

BACKGROUND: We conducted an annual urine glucose screening program at schools, and diagnosed schoolchildren with diabetes at an early stage of the disease. We also identified some cases of renal glucosuria (RG), based on positive urine glucose with normal glucose tolerance. METHODS: During 2000-2015, 3 309 631 schoolchildren participated in the screening program. The positive rate for glucosuria in the first test was approximately 0.1%, whereas on repeat urine test it was approximately 0.05%. In total 350 schoolchildren were positive for glucosuria on detailed examination. Oral glucose tolerance test (OGTT) was also used to evaluate glucose intolerance. RESULTS: One hundred and two schoolchildren (29.7%) were diagnosed with diabetes, whereas RG was identified in 246 (70.3%) with normal glucose metabolism. In regard to the characteristics of RG, the percentage of boys was 50.3%, and the mean age at diagnosis was 11.2 ± 2.4 years. Twenty-eight children (11.4%) were overweight (body mass index standard deviation score [BMI-SDS] > +2.0 SD), whereas five (2.0%) were underweight (BMI-SDS < -2.0 SD). First-degree family history was suspected in 176 cases (71.5%). All RG subjects had normal glucose tolerance in the absence of insulin resistance and decreased insulin secretion (homeostasis model assessment for ß-cell function, 78.8 ± 59.5%) on OGTT. CONCLUSIONS: RG is not rare in Japanese schoolchildren with glucosuria. This disorder seems to have a strong genetic background, and to involve less growth retardation and weight loss than expected despite continuous excretion of glucose in urine.

Renal glucosuria is not associated with atherosclerotic cardiovascular disease outcome in a general Japanese community.

BACKGROUND AND AIMS: Renal glucosuria is defined as the excretion of detectable amounts of glucose in the urine without diabetes or hyperglycemia. Few data exist regarding the prevalence of renal glucosuria and its clinical impact on atherosclerotic cardiovascular diseases. METHODS: This study included 47,842 subjects (16,913 men, 35.4%) aged ≥40 years who underwent the Japanese specific health checkup in Kanazawa City during 2014. We defined renal glucosuria as fulfillment of all of the following three criteria: 1) detectable glucosuria; 2) the absence of diabetes; 3) normal blood glucose (<110 mg/dl fasting, and <140 mg/dl non-fasting). The presence of renal glucosuria and of factors associated with atherosclerotic cardiovascular diseases, including coronary artery disease and stroke, was assessed. RESULTS: The criteria for renal glucosuria were met by 665 (1.4%) subjects. Significantly higher proportions of subjects with renal glucosuria exhibited coronary artery disease, stroke, or either outcome than those without (14.9% vs. 12.1%, p = 0.0305; 9.9% vs. 6.9%, p = 0.00255; 22.3% vs. 17.0%, p = 4.0 × 10-4, respectively), but multivariate logistic regression analyses revealed that renal glucosuria was not associated with coronary artery disease (odds ratio [OR] = 0.940, 95% confidence interval [CI] = 0.748-1.171, not significant), stroke (OR = 1.122, 95% CI = 0.853-1.453, not significant), or atherosclerotic cardiovascular diseases (OR = 1.122, 95% CI = 0.853-1.453, not significant). CONCLUSIONS: These results indicate that the prevalence of renal glucosuria in the Japanese general population was 1.4%, and that renal glucosuria was not associated with atherosclerotic cardiovascular diseases per se.

Pregnancy-associated polyuria in familial renal glycosuria.

A pregnant woman presented at gestational week 28 with loss of consciousness and profound polyuria. Further characterization revealed osmotic diuresis due to massive glycosuria without hyperglycemia. Glycosuria reduced substantially postpartum, from approximately 100 to approximately 30 g/1.73 m2 per day. DNA sequencing analysis of the SLC5A2 gene encoding the renal glucose transporter SGLT2 showed a homozygous frame-shift mutation (occurring after the glutamine at amino acid 168 and leading to premature termination of the protein at amino acid 186) diagnostic of familial renal glycosuria. Pregnant women with familial renal glycosuria can be at risk of profound polyuria during pregnancy due to the associated increase in glycosuria. These findings also have implications for the use of SGLT2 inhibitors in clinical practice.

[Renal glycosuria: report of two cases]. / Glicosúria renal: a propósito de dois casos clínicos.

Glycosuria as an accidental finding implies a diagnostic workout. We present the cases of two asymptomatic female teenagers referred to a hospital outpatient clinic due to isolated glycosuria detected in a routine analysis. The diagnostic workout revealed isolated glycosuria in the absence of other abnormalities. The genetic study confirmed the diagnosis of renal glycosuria, by revealing SCL5A2 gene mutations. Renal glycosuria is characterized by persistent glycosuria in the absence of hyperglycaemia or generalized renal tubular dysfunction. It's usually asymptomatic and has good prognosis. The authors call the attention to this rare entity, since it can be the reason for reference to a hospital outpatient clinic, underlining the importance of a differential diagnosis with more serious diseases that require proper treatment.

Glicosúria renal: a propósito de dois casos clínicos / Renal glycosuria: report of two cases

A glicosúria como achado acidental implica um estudo etiológico. Apresentam-se os casos de duas adolescentes do sexo feminino, assintomáticas, referenciadas por glicosúria detectada em análise de rotina. Negavam infecções, traumatismos e ingestão de fármacos ou tóxicos. O estudo efetuado confirmou glicosúria na ausência de outras alterações. O estudo genético revelou a presença de mutações do gene SCL5A2, confirmando o diagnóstico de glicosúria renal. A glicosúria renal familiar caracteriza-se por glicosúria isolada persistente na ausência de hiperglicemia e de disfunção tubular renal generalizada. É, geralmente, assintomática e o prognóstico é favorável. Alerta-se para esta rara entidade, pois pode ser motivo de referenciação para consulta de pediatria, salientando-se a importância do diagnóstico diferencial com afecções mais graves que necessitam de tratamento adequado.

Glycosuria as an accidental finding implies a diagnostic workout. We present the cases of two asymptomatic female teenagers referred to a hospital outpatient clinic due to isolated glycosuria detected in a routine analysis. The diagnostic workout revealed isolated glycosuria in the absence of other abnormalities. The genetic study confirmed the diagnosis of renal glycosuria, by revealing SCL5A2 gene mutations. Renal glycosuria is characterized by persistent glycosuria in the absence of hyperglycaemia or generalized renal tubular dysfunction. It's usually asymptomatic and has good prognosis. The authors call the attention to this rare entity, since it can be the reason for reference to a hospital outpatient clinic, underlining the importance of a differential diagnosis with more serious diseases that require proper treatment.

Reversible renal glycosuria in acute interstitial nephritis.

Renal glycosuria is defined as the excretion of glucose in urine in a normoglycemic state. It results from renal tubular dysfunction or immaturity of tubular function in the newborn. Etiologically, renal glycosuria is of 3 types-benign renal glycosuria, glycosuria with diabetes mellitus (including gestational diabetes) and tubular defects (Fanconi syndrome). Prognosis of benign renal glycosuria is excellent and reversible. Acute interstitial nephritis (AIN) is one of the main causes of acute renal failure and may often result in tubular dysfunction. In this study, the authors report the occurrence of AIN with acute renal failure that contributed to reversible renal glycosuria. The glycosuria observed in the patient of this study was an isolated tubular defect, with no phosphaturia, aminoaciduria or bicarbonaturia. Such a presentation is very rare in adults and has not been previously reported. These findings confirm that AIN with acute renal failure can cause an isolated tubular defect with benign reversible glycosuria in an adult.

Usefulness of HbA1c to diagnose diabetes among Japanese children detected by a urine glucose screening program in the Tokyo Metropolitan Area.

We examined the correlation between plasma glucose (PG) and hemoglobin A1c (HbA1c) to evaluate the usefulness and limitations of applying the new diagnostic criteria for diabetes to Japanese pediatric patients. Data were collected from 298 school children who took an oral glucose tolerance test (OGTT) at a school-based urinary glucose screening program in the Tokyo Metropolitan Area between 1988 and 2009. Mean (SD) age of the children was 11.9 (2.5) years. Male-to-female ratio was 1:1.1. Children were diagnosed with renal glucosuria (n=146), diabetes mellitus (n=133), or the Japan Diabetes Society (JDS) "borderline type" (n=19). Median (range) values of fasting plasma glucose (FPG), 2-h plasma glucose in an OGTT (OGTT-2h), and HbA1c were 101 (76-378) mg/dL, 146.5 (57-563) mg/dL, and 6.05 (4.7-14.1) %. The correlation between PG and HbA1c was analyzed using least squares regression, and HbA1c was found to highly correlate with PG. From estimated regression equations, mean values of FPG and OGTT-2h corresponding to an HbA1c of 6.5% were calculated to be 111.4 mg/dL and 170.4 mg/dL. The mean values of HbA1c corresponding to an FPG of 126 mg/dL and OGTT-2h of 200 mg/dL were calculated to be 7.5% and 7.8%. The mean values of PG corresponding to HbA1c of 6.5% were lower than found in adults as analyzed by JDS. The mean values of HbA1c corresponding to diabetic type PG were higher than found in adults.

Multiple bone fracture due to Fanconi's syndrome in primary Sjögren's syndrome complicated with organizing pneumonia.

Abstract A 66-year-old woman showing renal dysfunction with elevated serum alkaline phosphatase and anti-SS-A antibody was admitted. A labial salivary gland biopsy showing infiltration of mononuclear cells and positive anti-SS-A antibody with sicca symptoms led to a diagnosis of primary Sjögren's syndrome (SS). Fanconi's syndrome was diagnosed by renal tubular acidosis along with renal glucosuria or aminoaciduria and multiple bone fractures on bone scintigraphy. Typical bilateral pulmonary shadows were confirmed as organizing pneumonia (OP) determined by the analysis of bronchoalveolar lavage fluid and transbronchial lung biopsy. A rare complication of Fanconi's syndrome with OP in SS is described.

[Juvenile cataract associated with microcornea and glucosuria: a new syndrome]. / Juvenile Katarakt assoziiert mit Mikrokornea und Glukosurie: Ein neues Syndrom.

BACKGROUND: Predisposition is responsible for approximately 50% of age-related cataracts. Investigation of inherited forms of cataract provides the opportunity to identify the genes that may play a role in age-related cataract as well. PATIENTS AND METHODS: We describe the phenotype of a Swiss family with juvenile cataract, associated with microcornea and renal glucosuria. 11 of 17 family members in three generations underwent ophthalmic assessment and urine analysis. Medical records or questionnaires were evaluated in the remaining six cases. RESULTS: Eleven family members had progressive juvenile cataract. Eight affected members available for clinical examination had bilateral microcornea, not associated with microphthalmos. Furthermore, renal glucosuria was demonstrated in six of these persons. The mode of inheritance is autosomal-dominant. CONCLUSIONS: We have defined a new syndrome, consisting of the association of juvenile cataract, microcornea and renal glucosuria. The pattern of inheritance is autosomal-dominant. Genotyping is ongoing.

Transient renal tubulopathy in a racing Greyhound.

A 2-year-old female Greyhound was presented for inappetence and lethargy. On referral, results of diagnostic tests indicated renal glucosuria, increased excretion of selected amino acids and abnormal fractional excretion of electrolytes consistent with renal tubular dysfunction. Systemic blood pressure was elevated. Renal biopsy revealed mild proximal renal tubular damage consistent with a subacute toxic or hypoxic insult. Systemic hypertension, renal glucosuria and altered fractional excretion of electrolytes resolved during the 7 day period of hospital treatment. The Greyhound resumed training without recurrence of renal dysfunction.

Serum fructosamine measurement: a new diagnostic approach to renal glucosuria in dogs.

Measurement of serum fructosamine, 1-amino-1-deoxyfructose, is commonly used in diagnosing and monitoring hyperglycaemic disorders, such as diabetes mellitus in dogs. Serum fructosamine indicates long-term serum glucose concentrations and replaces serial serum glucose measurements. This study investigates the clinical usefulness of serum fructosamine in differentiating conditions other than diabetes mellitus characterised by glucosuria. Four dogs presented with glucosuria all had serum fructosamine concentrations within or close to the reference range (313 micromol 1(-1), 291 micromol 1(-1), 348 micromol 1(-1), 262 micromol 1(-1) reference range: 250 to 320 micromol 1(-1) indicating that a single serum fructosamine measurement is a simple and efficient way of verifying concurrent persistent normoglycaemia. Therefore, serum fructosamine is a useful parameter not only in diabetic patients, bu also in differentiating conditions in dogs characterised by glucosuria without hyperglycaemia, such as primary renal glucosuria and the Fanconi syndrome. To distinguish between primary renal glucosuria and the Fanconi syndrome, measurement of the amino acid concentration in urine was performed.

Transient renal glucosuria in patients with tetanus.

BACKGROUND/AIMS: During our early years of experience with patients suffering from tetanus, some of them were found to have unexplained renal glucosuria. METHODS: Thus, all the normoglycemic patients with tetanus who were consecutively encountered over the subsequent 8 years were studied for the presence of renal glucosuria. RESULTS: From 92 cases of tetanus admitted to the intensive-care unit, 63 patients had normal blood sugar in the course of their illness. The quantitative measurement of 24-hour urine confirmed the presence of significant renal glucosuria in 52% (n = 33) of these cases. The renal glucosuria was of transient nature and decreased to normal levels in the recovery stage (4 weeks after discharge from the hospital). There was no significant difference in age, sex, severity of disease and site of entry between the two groups of the patients with and without renal glucosuria. CONCLUSION: Significant but transient glucosuria of renal origin possibly induced by tetanospasmin is common in patients with tetanus.

Renal glycosuria treated as diabetes mellitus: case report.

A case of renal glycosuria is reported. A 55 year old female was diagnosed and treated in an upcountry hospital for diabetes mellitus. She developed symptoms of hypoglycaemia while on an oral hypoglycaemic agent, leading to her admission in Mulago Hospital. Persistent glycosuria was noted despite treatment and normal serum glucose. Oral glucose tolerance test and timed urine glucose showed a normal curve but high urine sugar. A diagnosis of renal glycosuria was made, oral hypoglycaemic therapy was stopped, patient improved and was discharged. Though renal glycosuria is a benign condition, mistaken diagnosis for diabetes mellitus puts patients at risk of hypoglycaemia due to treatment. Diagnosis of the condition requires physicians' awareness of its existence in our community and the use of Marbles' criteria obviates confusion with diabetes mellitus though it does not absolutely exclude Fanconi syndrome.

Hypercalciuria in renal glucosuria.

Primary renal glucosuria is a benign condition in which serum glucose level is normal. Idiopathic hypercalciuria is defined as increased urinary calcium excretion of more than 4 mg/kg/day in normocalcemic individuals in whom all known causes of hypercalciuria have been excluded. In this paper, we report on a case who has both renal glucosuria and hypercalciuria.

Glicosuria renal - diagnostico laboratorial / Renal glycosuria - laboratorial diagnostic

O presente trabalho mostra o grave risco que poderemos correr, se nos basearmos apenas na glicosuria para diagnosticarmos uma hiperglicemia