Doctors discovered a new genetic mutation in a 19-year-old girl that causes a rare condition called Fanconi-Bickel syndrome. This condition affects how the body processes sugar and minerals, leading to weak bones, stunted growth, and lung problems. The girl had struggled since infancy with delayed development and poor nutrition. Through genetic testing, doctors identified a previously unknown mutation in a gene that controls how cells transport sugar. With proper treatment including vitamins and dietary changes, the girl’s health improved. This discovery helps doctors better understand this rare inherited disease and could help other families affected by similar genetic mutations.

The Quick Take

  • What they studied: A rare genetic disease called Fanconi-Bickel syndrome caused by a new mutation that doctors had never seen before
  • Who participated: One 19-year-old girl from a family where parents are related by blood (which increases the chance of rare genetic diseases)
  • Key finding: Doctors found a new genetic mutation in the SLC2A2 gene that causes Fanconi-Bickel syndrome. This is the first time this specific mutation has been reported worldwide.
  • What it means for you: If you have a family history of genetic disorders or unexplained growth problems and weak bones, genetic testing might help identify the cause. This discovery helps doctors recognize and treat similar cases in the future.

The Research Details

This is a case report, which means doctors documented the medical story of one patient in detail. The 19-year-old girl came to the hospital with several health problems that had started in infancy: delayed development, a swollen belly, poor growth, and lung disease. Doctors initially thought she had a different bone disease called resistant rickets, but her symptoms didn’t fully match that diagnosis.

To find the real cause, doctors performed whole-exome sequencing, which is like reading the instruction manual for all the genes in her body to find errors. This genetic test revealed a mutation in a specific gene called SLC2A2 that controls how cells transport sugar. The girl had two copies of this mutated gene (one from each parent), which is why she developed the disease.

The doctors then treated her with vitamins, minerals, and dietary changes to manage her symptoms. They followed her progress over time and saw improvement in her growth.

Case reports are important because they document rare diseases that doctors might not see often. By publishing this case, other doctors around the world can learn about this new genetic mutation and recognize it in their own patients. This helps improve diagnosis and treatment for people with similar genetic conditions.

This is a single case report, so it describes one person’s experience rather than comparing many patients. While the genetic testing is reliable and the diagnosis is confirmed, we cannot draw broad conclusions about how common this mutation is or how it affects all patients. The value of this report is in documenting a new discovery that other doctors can learn from.

What the Results Show

The girl presented with multiple health problems starting in infancy: her motor development was delayed (she reached physical milestones like walking later than typical), she had a noticeably swollen belly, and she failed to gain weight and grow normally. By age 19, she showed signs of malnutrition and weak bones (rickets).

Laboratory tests revealed several problems: her kidneys were not properly regulating acid levels in her blood (proximal renal tubular acidosis), her cholesterol and fat levels were abnormal (dyslipidemia), her blood sugar was high after eating (postprandial hyperglycemia), and her alkaline phosphatase enzyme was elevated. Imaging showed weak bones throughout her skeleton and an enlarged liver.

The genetic test identified a homozygous missense variant in the SLC2A2 gene at position p.Glu486Gly. This means both copies of the gene (one from each parent) contained the same error, and this error changed one amino acid in the protein that transports sugar into cells. This genetic mutation prevents cells from properly absorbing glucose (sugar), which disrupts multiple body systems.

With treatment including phosphorus supplementation, bicarbonate to correct acid levels, vitamin D, and dietary modifications, the girl’s condition stabilized and her height improved during follow-up.

The girl also developed serious lung complications including cor pulmonale (heart problems caused by lung disease), restrictive lung disease (lungs cannot expand fully), and pulmonary hypertension (high blood pressure in lung vessels). These complications likely developed because the genetic disorder affected multiple organ systems over many years. The enlarged liver (hepatomegaly) indicated that the liver was also affected by the metabolic problems caused by the mutation.

Fanconi-Bickel syndrome was first described in 1949 and is known to be caused by mutations in the GLUT2 gene (which is the same as SLC2A2). However, this specific mutation (p.Glu486Gly) has never been reported before in medical literature. This case adds to our understanding of how different mutations in this gene can cause the disease and expands the known genetic variations that cause Fanconi-Bickel syndrome.

This is a single case report, so we cannot determine how common this mutation is or whether all patients with this mutation will have the same symptoms and severity. We don’t know the long-term outcomes beyond the follow-up period described. The findings apply specifically to this patient and may not generalize to others with different mutations in the same gene. Additionally, case reports cannot establish cause-and-effect relationships or compare treatment effectiveness.

The Bottom Line

If you have unexplained growth problems, weak bones, kidney issues, and high blood sugar starting in childhood, ask your doctor about genetic testing for Fanconi-Bickel syndrome. Treatment should include vitamin D, phosphorus, bicarbonate supplementation, and careful dietary management. Regular monitoring of kidney function, blood sugar, and bone health is important. Genetic counseling is recommended for families with this condition to understand inheritance patterns and prenatal testing options. (Confidence: High for diagnosis and management approach based on this case and established medical knowledge)

This information is most relevant to: families with a history of genetic disorders, people with unexplained growth failure and weak bones, patients with kidney problems and high blood sugar, and healthcare providers who treat rare genetic diseases. People without symptoms or family history of genetic disorders do not need to be concerned about this specific mutation.

Improvements in growth and overall health may take several months to become noticeable with proper treatment. Long-term management requires ongoing monitoring and adjustment of medications and diet. The lung complications in this case developed over many years, suggesting that early diagnosis and treatment might help prevent such serious complications.

Want to Apply This Research?

  • If you have Fanconi-Bickel syndrome or a similar genetic condition, track your height/growth monthly, blood sugar levels after meals, and kidney function test results (bicarbonate and phosphorus levels) every 3 months to monitor treatment effectiveness.
  • Users with this condition should use the app to: set reminders for vitamin D and phosphorus supplements, log meals to track carbohydrate intake, record any symptoms like fatigue or bone pain, and maintain a log of medical appointments and lab results to share with their doctor.
  • Create a long-term dashboard showing trends in height growth, blood sugar control, and kidney function markers over months and years. Set alerts when lab values fall outside normal ranges. Generate monthly reports to discuss with your healthcare team to adjust treatment as needed.

This article describes a single case of a rare genetic disease and should not be used for self-diagnosis. Fanconi-Bickel syndrome requires specialized medical care from doctors experienced in genetic and metabolic disorders. If you or a family member has symptoms like unexplained growth problems, weak bones, kidney issues, or high blood sugar, consult with a healthcare provider for proper evaluation and genetic testing. This information is educational and does not replace professional medical advice. Genetic counseling is recommended for families with confirmed cases of Fanconi-Bickel syndrome.