A Case Study of a Rare Disease (Fructosemia) Diagnosed in a Patient with Abdominal Pain.

Hereditary fructose intolerance is a rare genetic disorder that is inherited in an autosomal recessive manner, with mutations sometimes occurring spontaneously. Consuming fructose triggers biochemical abnormalities, disrupting liver processes like glycogenolysis and gluconeogenesis. Recent studies have revealed elevated intrahepatic fat levels in affected individuals. Symptoms include aversion to fructose-containing foods, hypoglycemia, liver and kidney dysfunction, and growth delays, with severe cases leading to liver enlargement, fatty liver disease, kidney failure, and life-threatening hypoglycemia. In this case study, we present a 20-month-old child with symptoms including difficulty passing stool, abdominal rigidity, abdominal pain with bloating and hypoglycemia. Initial clinical findings revealed elevated liver enzymes, a mildly enlarged hyperechoic liver, hypercholesterolemia, and borderline alpha-fetoprotein values. Diagnostic assessments identified hereditary fructose intolerance (HFI) with pathogenic variants in the ALDOB gene, along with a diagnosis of celiac disease. Genetic testing of the parents revealed carrier status for pathological aldolase B genes. This case underscores the importance of comprehensive clinical evaluation and genetic testing in pediatric patients with complex metabolic presentations.

Clinical Practice Guidelines for the Diagnosis and Management of Hereditary Fructose Intolerance.

INTRODUCTION: Hereditary fructose intolerance or hereditary fructosemia is an autosomal recessive metabolic disorder caused by a loss of function in the aldolase B gene. This disorder affects 1 in 20,000 people, constituting a rare disease with a favorable prognosis through adherence to a fructose-free diet. Despite dietary management, chronic pathology may manifest, underscoring the importance of early diagnosis to mitigate adverse effects. However, early detection of the disease poses significant challenges. AIM: Our aim was to compile pertinent information on the differential diagnosis of this pathology based on patient symptoms, facilitating the development of a diagnostic algorithm for early identification. METHODOLOGY: A systematic review adhering to PRISMA guidelines was conducted on empirical studies from PubMed, encompassing a total of 35 studies. RESULTS: Individuals with fructose intolerance may acutely experience postprandial symptoms such as hypoglycemia, vomiting, and abdominal distension. Despite proper treatment, chronic complications such as fatty liver, Fanconi syndrome, growth deficiency, and irritable bowel syndrome may arise. The proposed diagnostic algorithm aims to minimize these adverse processes. CONCLUSIONS: Understanding the pathogenesis enables prompt diagnosis and prevention of chronicity. Establishing continuity of care from pediatric to adult medicine is crucial, and disseminating information to non-pediatric endocrinologists is imperative for managing this rare disease.

Assessment of dietary interventions including low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet as management for fructose intolerance.

OBJECTIVES: Abdominal pain remains one of the most common referral reasons to pediatric gastroenterology. Dietary intolerances are often considered but due to various factors are hardly pursued. We observed that diet review in large number of children with abdominal pain was high in sugary foods which led to food intolerance investigation and dietary intervention. METHODS: A retrospective review was conducted of patients presenting with abdominal pain, diarrhea, or vomiting and negative GI evaluation, who underwent fructose breath testing. Patients younger than 20 years old who were seen between June 1, 2018 and March 1, 2021 were included. Statistical analysis was performed in R. RESULTS: There were 110 pediatric patients during the study period who underwent fructose breath testing, with 31% male and 69% female. The average age was 12.14 ± 4.01 years, and the average BMI was 21.21 ± 6.12. Abdominal pain was the most common presenting symptom (74.5%) followed by diarrhea and vomiting. Seventy-seven patients (70%) had a positive fructose breath test and were diagnosed with dietary intolerance to fructose. The 56 (67.5%) of those patients experienced symptoms during the breath test. Forty-three patients improved with dietary intervention. Twenty-seven on low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet and 16 on other diets. CONCLUSIONS: Based on analysis of our cohort of children with abdominal pain and high incidence of fructose intolerance as well as improvement in symptoms, following dietary changes, this condition should be considered and treated. Further investigation is needed to improve diagnostic testing but also into understanding mechanisms behind symptom presentation in this population.

Descriptive Analysis of Carrier and Affected Hereditary Fructose Intolerance in Women during Pregnancy.

(1) Background: Hereditary fructose intolerance (HFI) is a rare autosomal recessive metabolic disorder resulting from aldolase B deficiency, requiring a fructose, sorbitol and sucrose (FSS)-free diet. Limited information exists on the relationship between pregnancy outcomes and HFI. This study aims to analyze pregnancy-related factors in a cohort of thirty Spanish women, with twenty-three being carriers and seven being HFI-affected (45 pregnancies). (2) Methods: A descriptive, cross-sectional and retrospective study utilized an anonymous questionnaire. (3) Results: Findings encompassed physical and emotional states, nutritional habits, pathology development and baby information. Notable results include improved physical and emotional states compared to the general population, with conventional analyses mostly within normal ranges. Persistent issues after pregnancy included hepatic steatosis, liver adenomas and hemangiomas. Carrier mothers' babies exhibited higher weight than those of patient mothers, while the weights of carrier children born with HFI were similar to disease-affected children. (4) Conclusions: Pregnant women with HFI did not significantly differ in physical and emotional states, except for nausea, vomiting, and cravings. Post-pregnancy, HFI patients and carriers exhibited persistent hepatic issues. Significantly, babies born to HFI-affected mothers had lower weights. This study sheds light on pregnancy outcomes in HFI, emphasizing potential complications and the need for ongoing monitoring and care.

Design of mobile and website health application devices for drug tolerability in hereditary fructose intolerance.

BACKGROUND: Hereditary fructose intolerance (HFI) is a rare metabolic disease caused by aldolase B deficiency. The aim of our study was to analyse excipient tolerability in patients with HFI and other related diseases and to design mobile and website health applications to facilitate the search for drugs according to their tolerance. RESULTS: A total of 555 excipients listed in the Spanish Medicines Agency database (July 2023) were classified as suitable for HFI patients, suitable with considerations ((glucose and glucose syrup, intravenous sucrose, oral mannitol, polydextrose, gums and carrageenans, ethanol, sulfite caramel and vanilla), not recommended (intravenous mannitol) and contraindicated (fructose, oral sucrose, invert sugar, sorbitol, maltitol, lactitol, isomaltitol, fruit syrups, honey, sucrose esters and sorbitol esters). Glucose and glucose syrup were classified as suitable with considerations due to its possible fructose content and their potential endogenous fructose production. For other related intolerances, wheat starch was contraindicated and oatmeal was not recommended in celiac disease; oral lactose and lactose-based coprocessed excipient (Cellactose®) were not recommended in lactose intolerance; and glucose, invert sugar and oral sucrose were not recommended in diabetes mellitus. The applications were named IntoMed®. Results are listed in order of tolerability (suitable drugs appear first and contraindicated drugs at the end), and they are accompanied by a note detailing their classified excipients. If a drug contains excipients within different categories, the overall classification will be the most restrictive. The apps are also able to classify substances with the same criteria if they act as active ingredients. The tools exhibited good usability (82.07 ± 13.46 points on the System Usability Scale [range: 0-100]) on a sample of HFI patients, their families and health care professionals. CONCLUSIONS: IntoMed® is a tool for finding information about the tolerability of drugs according to excipients for patients with HFI and other related intolerances, with good usability. It is a fast and reliable system that covers the current excipient legislation and expands on it with other specific information: HFI patients should be alert for excipients such as mannitol (especially in intravenous drugs), fruit syrups, honey, sulfite caramel or vanilla. Glucose might contain or produce fructose, and special precaution is needed because of potential errors in their composition.

Myths and Facts about Food Intolerance: A Narrative Review.

Most adverse reactions to food are patient self-reported and not based on validated tests but nevertheless lead to dietary restrictions, with patients believing that these restrictions will improve their symptoms and quality of life. We aimed to clarify the myths and reality of common food intolerances, giving clinicians a guide on diagnosing and treating these cases. We performed a narrative review of the latest evidence on the widespread food intolerances reported by our patients, giving indications on the clinical presentations, possible tests, and dietary suggestions, and underlining the myths and reality. While lactose intolerance and hereditary fructose intolerance are based on well-defined mechanisms and have validated diagnostic tests, non-coeliac gluten sensitivity and fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) intolerance are mainly based on patients' reports. Others, like non-hereditary fructose, sorbitol, and histamine intolerance, still need more evidence and often cause unnecessary dietary restrictions. Finally, the main outcome of the present review is that the medical community should work to reduce the spread of unvalidated tests, the leading cause of the problematic management of our patients.

Development of tools to facilitate the diagnosis of hereditary fructose intolerance.

Although hereditary fructose intolerance (HFI) is an inborn error of fructose metabolism that classically presents at infancy, the diagnosis is often missed or delayed. In this study, we aimed to develop tools to facilitate the diagnosis of HFI. The intake of fructose-containing food products, that is, fruit, fruit juice and sugar-sweetened beverages, was assessed by a 3-day food diary in adult HFI patients (n = 15) and age, sex, and BMI-matched controls (n = 15). Furthermore, glycosylation of transferrin was examined using high-resolution mass spectrometry and abnormally glycosylated transferrin was expressed as ratio of normal glycosylated transferrin. We found that the sensitivity and specificity of the 3-day food diary for the intake of at least one fructose-containing food product were both 100%. Both mono-glyco:diglyco transferrin and a-glyco+mono-glyco:di-glyco transferrin were greater in HFI patients and had a high-discriminatory power (area under the receiver operating characteristic curve: 0.97 and 0.94, respectively). In this well-characterized cohort of adult HFI patients, the 3-day food questionnaire and the glycosylation pattern of transferrin are valuable tools to facilitate the recognition and diagnosis of HFI in adult patients.

Combined PMM2-CDG and hereditary fructose intolerance in a patient with mild clinical presentation.

We report a patient with an extremely rare, combined diagnosis of PMM2-CDG and hereditary fructose intolerance (HFI). By comparing with other patients, under-galactosylation was identified as a feature of HFI. Fructose/sorbitol/sucrose restriction was initiated right afterwards. The patient is at the mild end of the PMM2-CDG spectrum, raising the question of sorbitol's role in the pathogenesis of PMM2-CDG and whether fructose/sorbitol/sucrose restriction could benefit other PMM2-CDG patients. Additionally, epalrestat, an emerging potential PMM2-CDG therapy, may benefit HFI patients.

Hepatic but not Intestinal FBP1 Is Required for Fructose Metabolism and Tolerance.

Fructose intolerance in mammals is caused by defects in fructose absorption and metabolism. Fructose-1,6-bisphosphatase 1 (FBP1) is a key enzyme in gluconeogenesis, and its deficiency results in hypoglycemia as well as intolerance to fructose. However, the mechanism about fructose intolerance caused by FBP1 deficiency has not been fully elucidated. Here, we demonstrate that hepatic but not intestinal FBP1 is required for fructose metabolism and tolerance. We generated inducible knockout mouse models specifically lacking FBP1 in adult intestine or liver. Intestine-specific deletion of Fbp1 in adult mice does not compromise fructose tolerance, as evidenced by no significant body weight loss, food intake reduction, or morphological changes of the small intestine during 4 weeks of exposure to a high-fructose diet. By contrast, liver-specific deletion of Fbp1 in adult mice leads to fructose intolerance, as manifested by substantial weight loss, hepatomegaly, and liver injury after exposure to a high-fructose diet. Notably, the fructose metabolite fructose-1-phosphate is accumulated in FBP1-deficient liver after fructose challenge, which indicates a defect of fructolysis, probably due to competitive inhibition by fructose-1,6-bisphosphate and may account for the fructose intolerance. In conclusion, these data have clarified the essential role of hepatic but not intestinal FBP1 in fructose metabolism and tolerance.

Identification of a novel mutation in the ALDOB gene in hereditary fructose intolerance.

OBJECTIVES: Hereditary fructose intolerance (HFI) is caused by aldolase B enzyme deficiency. There has been no report about HFI from Iran and the type of mutations has not been reported in the Iranian population so far. CASE PRESENTATION: Herein we report a 2 year old girl presented with failure to thrive, hepatomegaly, and liver dysfunction. The primary impression has been hepatic glycogen storage disease type 1 or 6. This diagnosis was not confirmed by laboratory data and liver biopsy. Therefore, targeted-gene sequencing (TGS) covering 450 genes involved in inborn errors in metabolic diseases was performed. The results of TGS showed a rare novel homozygous pathogenic variant c.944del (p.Gly315ValfsTer15) in the ALDOB gene. CONCLUSIONS: This report introduces a novel variant that expands the mutational spectrum of the ALDOB gene in patients with HFI.

Sweet ending: When genetics prevent a dramatic CDG diagnostic mistake.

Herein, we described the case of a newborn male, from consanguineous parents, who developed, at day 11 of life, an obstructive hydrocephalus resulting from bilateral cerebellar hemorrhage without evident cause. Then, at 1 month, he developed a fulminant hepatitis with hyperammonia, hyperlactatemia and metabolic acidosis. Infectious and first line metabolic explorations were normal. Screening for congenital disorder of glycosylation (CDG) was performed using capillary electrophoresis and western blot of serum transferrin. Abnormal results were evocative of mannose-phosphate isomerase deficiency (MPI-CDG or CDG-Ib) as it can be responsible for fulminant hepatitis, digestive disease, developmental delay, and coagulopathy. However, trio whole exome sequencing revealed a pathogenic variant at the homozygous state in ALDOB, responsible for hereditary fructose intolerance (HFI), an inherited metabolic disorder with excellent prognosis under a fructose-free diet. HFI had not been previously evoked in view of the absence of diet diversification, but meticulous inquiry revealed that parents systematically added white sugar to the bottle milk of their child, unintentionally triggering potentially fatal HFI decompensations. Early genetic analysis upsetted both diagnosis and prognosis for this infant who had excellent development after fructose removal. This full-of-surprises diagnostic approach illustrates the importance of an integrative collaboration between clinicians, biochemists, and geneticists.

Chronic enteropathy associated with SLCO2A1 gene and hereditary fructose intolerance: A coincidence of two rare diseases.

Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a rare disorder characterized by multiple small intestine ulcers. Patients with CEAS typically present with chronic anemia and gastrointestinal bleeding. Besides CEAS, SLCO2A1 mutations cause primary hypertrophic osteoarthropathy (PHO) which is considered as an extraintestinal manifestation in CEAS patients. Since CEAS and Crohn's disease are clinically indistinguishable, patients are often misdiagnosed with Crohn's disease. Herein, we describe a 4-year-old Turkish girl with CEAS due to homozygous pathogenic variant (c.656C > T) in SLCO2A1 with concomitant hereditary fructose intolerance (HFI) caused by homozygous pathogenic variant (c.1005C > G) in ALDOB. Prompt restriction of fructose, sucrose and sorbitol resulted in hepatomegaly regression and mild amelioration of patient's symptoms. Despite budesonide and azathioprine treatments, patient's protein losing enteropathy and chronic anemia did not improve. Although previous CEAS cases were reported from East Asian countries, it is likely to occur in people from other geographic areas. CEAS seems to be underdiagnosed and high index of suspicion is required for the diagnosis of this rare entity. Patients with prior diagnosis of Crohn's disease with no response to immunosuppressive treatment or anti-TNF therapy should be re-evaluated for possible CEAS diagnosis.

Estimation of hereditary fructose intolerance prevalence in the Chinese population.

BACKGROUND: Hereditary fructose intolerance (HFI) caused by aldolase B reduction or deficiency that results in fructose metabolism disorder. The disease prevalence in the Chinese population is unknown, which impedes the formulation of HFI screening and diagnosis strategies. MATERIALS AND METHODS: By searching a local cohort (Chinese Children's Rare Disease Genetic Testing Clinical Collaboration System, CCGT) and public databases (ClinVar and Human Gene Mutation Database) and reviewing HFI-related literature, we manually curated ALDOB pathogenic or likely pathogenic (P/LP) variants according to ACMG guidelines. Allele frequency (AF) information from the local database CCGT and the public databases HuaBiao and gnomAD for ALDOB P/LP variants was used to estimate and the HFI prevalence in the Chinese population and other populations by the Bayesian framework. We collected the genotype and clinical characteristics of HFI patients from the CCGT database and published literature to study genotype-phenotype relationships. RESULT: In total, 81 variants of ALDOB were curated as P/LP. The estimated Chinese HFI prevalence was approximately 1/504,678, which was much lower than that for non-Finland European (1/23,147), Finnish in Finland (1/55,539), admixed American (1/132,801) and Ashkenazi Jewish (1/263,150) populations. By analyzing the genetic characteristics of ALDOB in the Chinese population, two variants (A338V, A338G) had significantly higher AFs in the Chinese population than in the non-Finland European population from gnomAD (all P values < 0.05). Five variants (A150P, A175D, N335K, R60*, R304Q) had significantly lower AFs (all P values < 0.1). The genotype-phenotype association analyses were based on 68 reported HFI patients from a literature review and the CCGT database. The results showed that patients carrying homozygous variant sites (especially A150P) were more likely to present nausea, and patients carrying two missense variant sites were more likely to present aversion to sweets and fruit (all P values < 0.05). Our research reveals that some gastrointestinal symptoms seem to be associated with certain genotypes. CONCLUSION: The prevalence of HFI in the Chinese population is extremely low, and there is no need to add HFI testing to the current newborn screening programs if medical costs are considered. A genetic testing strategy is suggested for early diagnosis of HFI.

Clinical and Metabolomic Effects of Lactiplantibacillus plantarum and Pediococcus acidilactici in Fructose Intolerant Patients

Fructose intolerance (FI) is a widespread non-genetic condition in which the incomplete absorption of fructose leads to gastro-intestinal disorders. The crucial role of microbial dysbiosis on the onset of these intolerance symptoms together with their persistence under free fructose diets are driving the scientific community towards the use of probiotics as a novel therapeutic approach. In this study, we evaluated the prevalence of FI in a cohort composed of Romanian adults with Functional Grastrointestinal Disorders (FGIDs) and the effectiveness of treatment based on the probiotic formulation EQBIOTA® (Lactiplantibacillus plantarum CECT 7484 and 7485 and Pediococcus acidilactici CECT 7483). We evaluated the impact of a 30-day treatment both on FI subjects and healthy volunteers. The gastrointestinal symptoms and fecal volatile metabolome were evaluated. A statistically significant improvement of symptoms (i.e., bloating, and abdominal pain) was reported in FI patient after treatment. On the other hand, at the baseline, the content of volatile metabolites was heterogeneously distributed between the two study arms, whereas the treatment led differences to decrease. From our analysis, how some metabolomics compounds were correlated with the improvement and worsening of clinical symptoms clearly emerged. Preliminary observations suggested how the improvement of gastrointestinal symptoms could be induced by the increase of anti-inflammatory and protective substrates. A deeper investigation in a larger patient cohort subjected to a prolonged treatment would allow a more comprehensive evaluation of the probiotic treatment effects.

Celiac Disease in Conjunction with Hereditary Fructose Intolerance as a Rare Cause of Liver Steatosis with Mild Hypertransaminasemia-A Case Report.

Celiac disease (CD) has been associated with several genetic and autoimmune disorders, but its association with hereditary fructose intolerance (HFI) is very rare. The possibility of an association between CD and HFI should be considered, especially in patients with a lack of improvement after a gluten-free diet. Children with HFI often present with a wide range of symptoms, however, data about a strong aversion to fruits and sweets may be helpful to establish the diagnosis. The diagnosis of HFI should be confirmed in genetic testing. Both CD and HFI may present with liver steatosis with hypertransaminasemia. In patients with these two disorders, the dietary restrictions of gluten and fructose improve clinical symptoms and protect them from secondary complications. We report the case of a child with the concurrence of these two disorders.

Reply letter to "safety of SARS-Cov-2 vaccines administration for adult patients with hereditary fructose intolerance".

In the letter, Urro et al. performed a search on the sucrose, fructose and sorbitol content in the approved Sars-Cov-2 vaccines and they concluded that these vaccines can be safely administered in adults affected by Hereditary fructose intolerance.The Pfizer-BioNTech COVID-19 Vaccine is currently approved for use in adolescents ≥ 12 years and the Moderna COVID-19 vaccine is close to approval for use in children over 12 years of age. Furthermore, both vaccines have initiated clinical trials that will include infant as young as 6 months. Therefore, we considerate important to analyze the safely administration of this two vaccines in children with Hereditary fructose intolerance.

Transferrin Isoforms, Old but New Biomarkers in Hereditary Fructose Intolerance.

Hereditary Fructose Intolerance (HFI) is an autosomal recessive inborn error of metabolism characterised by the deficiency of the hepatic enzyme aldolase B. Its treatment consists in adopting a fructose-, sucrose-, and sorbitol (FSS)-restrictive diet for life. Untreated HFI patients present an abnormal transferrin (Tf) glycosylation pattern due to the inhibition of mannose-6-phosphate isomerase by fructose-1-phosphate. Hence, elevated serum carbohydrate-deficient Tf (CDT) may allow the prompt detection of HFI. The CDT values improve when an FSS-restrictive diet is followed; however, previous data on CDT and fructose intake correlation are inconsistent. Therefore, we examined the complete serum sialoTf profile and correlated it with FSS dietary intake and with hepatic parameters in a cohort of paediatric and adult fructosemic patients. To do so, the profiles of serum sialoTf from genetically diagnosed HFI patients on an FSS-restricted diet (n = 37) and their age-, sex- and body mass index-paired controls (n = 32) were analysed by capillary zone electrophoresis. We found that in HFI patients, asialoTf correlated with dietary intake of sucrose (R = 0.575, p < 0.001) and FSS (R = 0.475, p = 0.008), and that pentasialoTf+hexasialoTf negatively correlated with dietary intake of fructose (R = -0.386, p = 0.024) and FSS (R = -0.400, p = 0.019). In addition, the tetrasialoTf/disialoTf ratio truthfully differentiated treated HFI patients from healthy controls, with an area under the ROC curve (AUROC) of 0.97, 92% sensitivity, 94% specificity and 93% accuracy.

Molecular and clinical findings of Turkish patients with hereditary fructose intolerance.

OBJECTIVES: Hereditary fructose intolerance (HFI) is an autosomal recessive disorder caused by a deficiency in aldolase B that can result in hypoglycemia, nausea, vomiting, abdominal pain, liver and kidney dysfunction, coma, and even death. This study aims to represent the clinical features and molecular genetic analysis data of the patients diagnosed with HFI in our study population. METHODS: The medical records of the 26 patients with HFI were evaluated retrospectively. Age, gender, clinical findings, metabolic crises, and the results of molecular analyses were recorded. RESULTS: The patients with HFI had a good prognosis and the aversion to sugar-containing foods was the main complaint. Seven different variants were identified in the Aldolase B (ALDOB) gene in HFI patients. The most frequent mutations were p.Ala150Pro, p.Ala175Asp had a prevalence of 61 and 30%, respectively, in agreement with the literature and other known variants were found with minor frequencies c.360-363del4(3.8%), p.Asn335Lys(3.8%), and three novel mutations c.113-1_15del4 (3.8%), p.Ala338Val(7.6%), and p.Asp156His(3.8%) were identified at a heterozygous, homozygous, or compound heterozygous level. CONCLUSIONS: This study results revealed three novel mutations in patients with HFI. On the basis of age of presentation, clinical symptoms, and metabolic crisis, there was no clear-cut genotype-phenotype correlation. This article also demonstrates the importance of screening suspected infants in cases of acute liver failure for prompt diagnosis and treatment of HFI.

Letter to the editor concerning the article 'Safety of vaccines administration in hereditary fructose intolerance'.

The most important approach for the management of hereditary fructose intolerance is a strict avoidance of fructose, sucrose and sorbitol from the diet and medications. A safe threshold of 2.4 mg/kg/dose was recently established by the Instituto Superiore di Sanità of Italy for both oral and parenteral routes, thus shouldering a safe administration of a majority of vaccines in these patients. This would not include, Rotarix® pre-established oral suspension and Rotateq® vaccines, which are indeed contraindicated. Moreover, Rotarix® white powder and solvent for oral suspension would only be safely administered at a weight above 9.3 kg.Overall, these recommendations to avoid rotavirus vaccination are difficult to implement because these vaccines are given during exclusive breastfeeding, prior to fructose-containing food introduction.