Glucose-galactose malabsorption with renal stones in a Saudi child

The Association between Dietary Sugar Intake and Nephrolithiasis: Results from National Health and Nutrition Examination Survey 2007-2018

BACKGROUND

Dietary sugar intake is gradually considered a risk factor for many diseases. A sugary diet was positively associated with risk of nephrolithiasis, but the specific relationships remain undefined.

OBJECTIVES

To determine associations between risk of nephrolithiasis and dietary sugar intake.

METHODS

This cross-sectional study involved 21,590 participants based on the National Health and Nutrition Examination Survey from 2007 to 2018. Amounts of dietary sugar intake (g/d) were the main exposure, including total sugar intake, added sugar intake, and food sources. Associations were analyzed by logistic regression models and restricted cubic splines using complex weighted designs.

RESULTS

Weighted mean intake [standard error] of total sugar and added sugar were 111.2 [2.0] g/d and 73.7 [1.9] g/d in participants with nephrolithiasis, respectively. In the fully adjusted regression model, compared to those in quartile 1, the population in quartile 4 of total sugar intake showed a significant risk of nephrolithiasis [odds ratio (OR): 1.23; 95% confidence interval (CI): 1.00-1.51]; OR for added sugar intake was 1.56 (95% CI: 1.25-1.94). The risks of nephrolithiasis increased steadily when total sugar and added sugar intake exceeded ∼150 g/d and 63 g/d in restricted cubic spline analyses, respectively. The highest sugar intake from beverages was associated with an increased risk of nephrolithiasis (OR for total sugar: 1.36; 95% CI: 1.07-1.72; OR for added sugar: 1.37; 95% CI: 1.09-1.73). Added sugar intake from meat, egg, and oil was significantly associated with risk of nephrolithiasis (quartile 4, OR: 1.22; 95% CI: 1.02-1.47), whereas total sugar intake from dairy products was in reverse (quartile 4, OR: 0.67; 95% CI: 0.54-0.82).

CONCLUSIONS

Total and added sugar intake, sugar intake from beverages, and added sugar intake from meat, egg, and oil were associated with an increased risk of nephrolithiasis, whereas total sugar intake from dairy products was negatively associated.

Literature review on congenital glucose-galactose malabsorption from 2001 to 2019

AIM

Congenital glucose-galactose malabsorption (CGGM) is a rare disease characterised by severe diarrhoea, dehydration and weight loss. To better understand CGGM, we investigated all the case reports and series of CGGM from 2001 to 2019.

METHODS

A review of reports of CGGM published from 2001 to 2019 was undertaken, using PubMed, Ovid Medline, Springer, Wanfang Database, CBMD database and CKNI database. The clinical features, diagnosis, treatment and prognosis of CGGM in these reports were obtained and analysed.

RESULTS

We reviewed 107 cases for this study. Out of 55 cases from Saudi Arabia and Turkey, 43 cases (78.2%) were from consanguineous marriage. Forty-nine cases (73.1%) were infants. Dehydration, diarrhoea and weight loss occurred in almost all cases. Half of the cases presented hypernatremia and abdominal distension. Vomiting, polyuria/haematuria and fever were reported in 11, 7 and 3 cases, respectively. Twenty cases (18.7%) showed hypercalcaemia or nephrolithiasis. Stool pH was tested in 43 cases (40.2%). Fifty-five cases (51.4%) were diagnosed for more than 1 month after the onset of symptoms. Two cases (1.9%) died, one needed amputation, and the other 104 cases (97.2%) recovered with fructose formula. Seventy-three cases (68.2%) underwent gene testing, 30 SLC5A1 gene mutations were detected, with 23 cases homozygous, and seven heterozygous mutation.

CONCLUSION

The clinical characteristics of CGGM are nonspecific, and the diagnosis method is not conventionally applied. Fasting and gene testing are the two most important diagnostic methods. The best treatment of CGGM is supplementation with fructose-based formula.

Glucose transporters in the small intestine in health and disease

Absorption of monosaccharides is mainly mediated by Na+-D-glucose cotransporter SGLT1 and the facititative transporters GLUT2 and GLUT5. SGLT1 and GLUT2 are relevant for absorption of D-glucose and D-galactose while GLUT5 is relevant for D-fructose absorption. SGLT1 and GLUT5 are constantly localized in the brush border membrane (BBM) of enterocytes, whereas GLUT2 is localized in the basolateral membrane (BLM) or the BBM plus BLM at low and high luminal D-glucose concentrations, respectively. At high luminal D-glucose, the abundance SGLT1 in the BBM is increased. Hence, D-glucose absorption at low luminal glucose is mediated via SGLT1 in the BBM and GLUT2 in the BLM whereas high-capacity D-glucose absorption at high luminal glucose is mediated by SGLT1 plus GLUT2 in the BBM and GLUT2 in the BLM. The review describes functions and regulations of SGLT1, GLUT2, and GLUT5 in the small intestine including diurnal variations and carbohydrate-dependent regulations. Also, the roles of SGLT1 and GLUT2 for secretion of enterohormones are discussed. Furthermore, diseases are described that are caused by malfunctions of small intestinal monosaccharide transporters, such as glucose-galactose malabsorption, Fanconi syndrome, and fructose intolerance. Moreover, it is reported how diabetes, small intestinal inflammation, parental nutrition, bariatric surgery, and metformin treatment affect expression of monosaccharide transporters in the small intestine. Finally, food components that decrease D-glucose absorption and drugs in development that inhibit or downregulate SGLT1 in the small intestine are compiled. Models for regulations and combined functions of glucose transporters, and for interplay between D-fructose transport and metabolism, are discussed.

Two Cases of Mistaken Polyuria and Nephrocalcinosis in Infants with Glucose-Galactose Malabsorption: A Possible Role of 1,25(OH)2D3

BACKGROUND/AIMS

Glucose-galactose malabsorption (GGM) is a rare and potentially fatal disorder. The autosomal recessive mutation of the SGLT1 gene interferes with the active glucose transport in the gut resulting in osmotic diarrhea and failure to thrive (FTT). Two nonrelated infants with GGM are presented as well as a novel mutation in SGLT1.

CASE PRESENTATION

The first case consulted for FTT and presented with hypercalcemia and hypercalciuria. His mother had self-medicated with high doses of vitamin D. The second case consulted for macroscopic hematuria, and presented with dehydration and secondary acute kidney injury. In both cases, the profuse diarrhea, initially mistaken for polyuria, promptly resolved after the introduction of glucose-galactose-free milk. Investigations showed bilateral nephrocalcinosis and high levels of 1,25(OH)2D3 in both patients. We hypothesize that the upregulation of epithelial calcium channels (TRPV6) and 1,25(OH)2D3 are possible factors involved in the pathophysiology of nephrocalcinosis sometimes seen in GGM. Furthermore, a novel intronic SGLT1 mutation (c.207+2dup) is described.

CONCLUSION

These 2 cases demonstrate that a malabsorption disorder such as GGM can present with nephrocalcinosis and/or hypercalcemia, with increased 1,25(OH)2D3 levels in infants. Prompt recognition of GGM is sometimes difficult but crucial.
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SLC5A1 Mutations in Saudi Arabian Patients With Congenital Glucose-Galactose Malabsorption

Congenital glucose-galactose malabsorption (cGGM) is a rare autosomal recessive disorder, caused by mutations in the SLC5A1 gene, encoding the sodium/glucose cotransporter 1, which may result in severe life-threatening osmotic diarrhea due to the accumulation of unabsorbed sugars in the intestinal lumen. If treated early with elimination of glucose and galactose from the diet, patients usually recover and develop normally. We present clinical and molecular data from 16 unrelated cGGM diagnosed Saudi patients from consanguineous families with majority of them having previous positive family history of cGGM. Sanger sequencing for the full coding regions of SLC5A1 for all patients resulted in the identification of 4 allelic variants in a homozygous state. Two mutations are novel; c.265G>A (p.G89R) and c.1304 G>A (p.G435D), and 2 have been previously reported to cause cGGM, c.765 C>G (p.C255W) and c.1136 G>A (p.R379Q). This is the first report delineating the clinical and molecular basis of cGGM in patients from this region.

Nephrocalcinosis in glucose-galactose malabsorption: nephrocalcinosis and proximal tubular dysfunction in a young infant with a novel mutation of SGLT1

We report an association of proximal renal tubular dysfunction in a 50-day-old girl with glucose-galactose malabsorption who was found to have nephrocalcinosis, but no sign of nephrolithiasis. A novel homozygous nonsense mutation at 267Arg-->stop (CGA-->TGA) in the Na(+)-dependent glucose transporter (SGLT1) was found in loop 5 connecting transmembrane segments 6 and 7, indicating the complete loss of glucose transport activity. This case indicates that hypercalcaemia, nephrocalcinosis and proximal tubular dysfunction may be seen in association with glucose-galactose malabsorption and that most of these abnormalities improve with a glucose-galactose-free diet.

Nephrocalcinosis in glucose-galactose malabsorption, association with renal tubular acidosis

We report an association of renal tubular acidosis (RTA) in two children with glucose-galactose malabsorption (GGM), who were found to have nephrocalcinosis. Although GGM has been reported previously with nephrocalcinosis, this report is the first to show that renal tubular acidosis could explain the coexistence of nephrocalcinosis in patients with glucose galactose malabsorption.

Genetic Hypercalciuria

Hypercalciuria is an important, identifiable, and reversible risk factor in stone formation. The foremost and most fundamental step in dissecting the genetics of hypercalciuria is understanding its pathophysiology. Hypercalciuria is a complex trait. This article outlines the various factors that compromise the attempt to dissect the genetics of hypercalciuria, summarizes the clinical and experimental monogenic causes of hypercalciuria, and outlines the initial results from attempts in studying polygenic hypercalciuria. Finally, the problem is set in perspective of the current database, technologic advances and limitations are highlighted, and prospects of further advances in the field are speculated upon.

Nephrolithiasis in a child with glucose-galactose malabsorption

Glucose-galactose malabsorption (GGM) is a rare autosomal recessive disorder of intestinal transport of glucose and galactose, leading to watery diarrhea, dehydration, failure to thrive, or early death. We report a female newborn with GGM, whose clinical diagnosis was confirmed by mutational analysis of the SGTL1 gene. Bilateral nephrolithiasis was discovered after an episode of hematuria. Metabolic causes of nephrolithiasis were not found. The most likely explanation for the development of nephrolithiasis is chronic diarrhea leading to dehydration and highly concentrated urine. High fluid intake and rigorous prevention of dehydration is therefore advised for these patients. Furthermore, life-long monitoring of their renal status, including regular ultrasound examinations, is warranted.

Neonatal nephrocalcinosis in association with glucose-galactose malabsorption

We report a case of severe nephrocalcinosis related to hypercalcaemia in a newborn with glucose-galactose malabsorption. He presented with poor growth and was noted to have polyuria, which was later recognised to be severe watery diarrhoea. We discuss the possible aetiological factors for nephrocalcinosis in this condition.

Nutrition management of congenital glucose-galactose malabsorption: a case study

In this article we describe the clinical history, diagnostic evaluation, and management of an infant who had congenital glucose-galactose malabsorption (CGGM)--a rare disorder thought to be inherited as an autosomal recessive trait. Because of defective sodium-coupled cotransport of glucose and galactose in the intestinal mucosa, infants with CGGM suffer from chronic, profuse, watery diarrhea that often leads to hypertonic dehydration. This infant experienced persistent diarrhea and hypernatremic dehydration during the first 3 months of life. Despite management with elemental formulas and continuous nasogastric feedings during initial hospitalizations, worsening diarrhea and dehydration persisted and malnutrition occurred. Diagnostic evaluations ruled out cystic fibrosis and bacterial or viral gastroenteritis. Diagnostic tests also revealed normal pancreatic exocrine function and normal villus architecture. The persistence of glucose-positive, watery diarrhea, even when the infant was fed an oral electrolyte solution, led to the diagnosis of CGGM. The infant was treated successfully with a carbohydrate-free infant formula to which fructose was added incrementally to meet energy requirements. Parental education about dietary management of CGGM with specialized formula supplemented with fructose and solid food feedings was an important component of this infant's nutrition therapy. Aggressive nutrition intervention for the infants and judicious dietary counseling for parents can lead to normal growth and neurological development for an infant with CGGM.

Congenital glucose-galactose malabsorption in Arab children

Eight children with chronic diarrhea from glucose-galactose malabsorption from eight different families are presented. Six children are Saudi Arabs and two are of the other Arab nationalities. The mean age of the children at the time of presentation was 10.6 months. They were first seen for chronic watery diarrhea, present since birth, and failure to thrive. Laboratory investigations, including small-bowel biopsy, histology, and small-bowel enzyme assay, confirmed the diagnosis of glucose-galactose malabsorption. One child had a renal stone at the first visit, and another was discovered to have one on follow-up. All the children responded clinically to fructose-based formula, and they are thriving at follow-up.

Aetiology of chronic diarrhoea in children: experience at King Khalid University Hospital, Riyadh, Saudi Arabia

Forty-eight cases of chronic diarrhoea in children seen at King Khalid University Hospital over a 5-year period were analysed. The mean age at presentation was 1.8 years (range 0.08-10 years); 34 were boys and 14 girls. Forty-four patients were Saudi and four were non-Saudi Arabs. Most children presented with failure to thrive and pallor. The aetiological factors identified were: the post-gastro-enteritis syndrome with or without lactose intolerance in 16 (33%); coeliac disease in ten (21%); congenital chloride diarrhoea in five (10%); glucose-galactose malabsorption and acrodermatitis enteropathica, each in three (6%); ulcerative colitis, intestinal lymphangiectasia, cow's milk protein intolerance and ataxia telangiectasia, each in two (4%); and giardiasis, immune deficiency and cystic fibrosis, each in one (2%). Five children died.