Background: Fructose-1,6-bisphosphatase (FBPase) deficiency is a rare autosomal recessive disorder of gluconeogenesis caused by biallelic pathogenic variants in the FBP1 gene. It presents with episodic hypoglycemia, lactic acidosis, and ketone body abnormalities, particularly during catabolic stress, but often mimics more common metabolic disorders, leading to diagnostic delays. Case Presentation: We describe the first genetically confirmed Albanian case of FBPase deficiency in a 3-year-old girl, born to nonsanguineous parents. The patient presented with recurrent episodes of vomiting, hypoglycemia, and metabolic decompensation since infancy. At her most severe presentation, she was admitted in a subcomatose state with profound hypoglycemia (35 mg/dL) and lactic acidosis (pH 6.9) without ketonuria. Whole exome sequencing identified a homozygous pathogenic FBP1 variant NM_000507.3(FBP1): c.472C > T; p. (Arg158Trp), a recurrent missense mutation associated with significant phenotypic variability. Parental testing confirmed autosomal recessive inheritance. Management and Outcome: Emergency management included intravenous dextrose and bicarbonate for metabolic acidosis, followed by nutritional interventions. The patient was advised to avoid fasting for more than 8 h and to limit fructose intake. No further metabolic crises were observed after these interventions. Conclusion: This case highlights the clinical and genetic complexity of FBPase deficiency and underlines the importance of genomic diagnostics in children with unexplained hypoglycemia and metabolic acidosis. Early diagnosis allows effective dietary management and prevents recurrent life-threatening episodes. As the first reported case in Albania, it contributes to the growing recognition of FBPase deficiency as an underdiagnosed but treatable metabolic disorder.

Hereditary fructose intolerance (HFI) is a rare genetic disorder of fructose metabolism due to aldolase B enzyme deficiency. Treatment consists of fructose, sorbitol, and sucrose (FSS)-free diet. We explore possible correlations between daily fructose traces intake and liver injury biomarkers on a long-term period, in a cohort of young patients affected by HFI. Patients' clinical data and fructose daily intake were retrospectively collected. Correlations among fructose intake, serum alanine aminotransferase (ALT) level, carbohydrate-deficient transferrin (CDT) percentage, liver ultrasonography, genotype were analyzed. We included 48 patients whose mean follow-up was 10.3 ± 5.6 years and fructose intake 169 ± 145.4 mg/day. Eighteen patients had persistently high ALT level, nine had abnormal CDT profile, 45 had signs of liver steatosis. Fructose intake did not correlate with ALT level nor with steatosis severity, whereas it correlated with disialotransferrin percentage (R2 0.7, p < 0.0001) and tetrasialotransferrin/disialotransferrin ratio (R2 0.5, p = 0.0001). p.A150P homozygous patients had lower ALT values at diagnosis than p.A175D variant homozygotes cases (58 ± 55 IU/L vs. 143 ± 90 IU/L, p = 0.01). A group of HFI patients on FSS-free diet presented persistent mild hypertransaminasemia which did not correlate with fructose intake. Genotypes may influence serum liver enzyme levels. CDT profile represents a good marker to assess FSS intake.

Hereditary fructose intolerance is an autosomal recessive disorder of fructose metabolism caused by catalytic deficiency of aldolase B enzyme [1]. The disease is typically expressed when fructose- and sucrose-containing foods are first introduced in the diet; acute manifestations include nausea, vomiting, abdominal distress, and symptomatic hypoglycemia [1,2]. Chronic fructose ingestion eventually leads to poor feeding, growth retardation and gradual liver and/or renal failure [3,4]. Some patients may remain undiagnosed until adulthood because of a self-protective avoidance of sweet tasting food that prevents the development of acute toxicity from fructose containing food; however, these subjects may suffer intermittent symptoms throughout life, leading to potentially serious misdiagnosis [4]. We report the case of a patient with unrecognized hereditary fructose intolerance in which chronic gastrointestinal complaints, low body weight, and unexplained food avoidance were addressed as manifestations of an eating disorder during adolescence.