Doctors discovered why a young woman had struggled with severe vitamin deficiencies since infancy. Using genetic testing at age 18, they found she had a rare mutation in a gene called SLC10A2 that prevents her body from properly absorbing bile acids—special substances needed to digest fats and fat-soluble vitamins. This case shows how genetic testing can finally solve medical mysteries that doctors couldn’t figure out for years. The findings suggest that people with unexplained vitamin deficiencies should get genetic testing earlier, which could help them get proper treatment sooner.

The Quick Take

  • What they studied: Why a patient had severe problems absorbing fat-soluble vitamins (vitamins A, D, E, and K) throughout her life, and what genetic cause was responsible
  • Who participated: One young female patient who had vitamin deficiencies since infancy but remained mostly symptom-free while taking vitamin supplements continuously
  • Key finding: A rare genetic mutation in the SLC10A2 gene prevented her body from absorbing bile acids properly—her body only retained 1.6% of bile acids instead of the normal amount, which is critical for vitamin absorption
  • What it means for you: If you or a family member has unexplained vitamin deficiencies that doctors can’t figure out, genetic testing may provide answers. However, this is a very rare condition, and most vitamin deficiencies have different causes. Talk to your doctor about whether genetic testing makes sense for your situation.

The Research Details

This is a case report, meaning doctors documented the medical story of one patient in detail. The patient had experienced severe fat-soluble vitamin deficiencies since infancy, but doctors couldn’t figure out why despite many tests over many years. When she turned 18, doctors performed exome sequencing—a genetic test that reads the instructions in her DNA to find mutations. This test revealed she had a homozygous variant in the SLC10A2 gene, meaning she inherited the same faulty gene from both parents. To confirm this was the problem, doctors performed a bile retention scan using radioactively labeled bile acids to measure how much her body was absorbing.

Case reports are important for identifying rare diseases and unusual presentations of genetic conditions. By documenting this patient’s journey, doctors can help other physicians recognize similar cases earlier. This approach also demonstrates how modern genetic testing can solve long-standing medical mysteries that traditional testing couldn’t explain. The detailed documentation helps the medical community understand a rare condition better.

As a single case report, this study describes one patient’s experience rather than comparing many patients. This means we can’t draw broad conclusions about how common this condition is or how it affects everyone with this mutation. However, case reports are valuable for identifying rare diseases and guiding future research. The use of genetic testing and specialized imaging (bile retention scan) strengthens the findings by providing objective evidence of the problem.

What the Results Show

The patient had a genetic mutation (Pro65Leu) in the SLC10A2 gene that she inherited from both parents. This gene normally produces a protein that acts like a shuttle, moving bile acids from the intestines back into the body so they can be reused. Without this working shuttle, bile acids couldn’t be reabsorbed properly. The bile retention scan confirmed this—her body only kept 1.6% of bile acids after 7 days, compared to the normal amount. This severe loss of bile acids meant her body couldn’t properly digest fats or absorb the fat-soluble vitamins (A, D, E, and K) that depend on bile acids to be absorbed. The patient remained relatively symptom-free only because she was continuously taking vitamin supplements to replace what her body couldn’t absorb naturally.

Doctors tried treating the patient with a bile acid sequestrant—a medication designed to help manage bile acid problems. However, the patient experienced side effects and the medication didn’t significantly improve her vitamin absorption, so treatment was stopped. This suggests that the specific type of bile acid malabsorption caused by this SLC10A2 mutation may not respond well to standard treatments, indicating that new treatment approaches may be needed for this condition.

This case adds to a small but growing body of research on SLC10A2 gene mutations and primary bile acid malabsorption. While bile acid malabsorption is known to cause fat-soluble vitamin deficiencies, cases caused specifically by SLC10A2 mutations are rare. This case report helps expand medical understanding of how this genetic mutation presents and progresses over time. It also highlights that some patients with this condition may remain relatively stable on vitamin supplementation, which differs from more severe presentations described in other cases.

This is a single case report, so findings apply only to this one patient. We don’t know how common this mutation is, how it affects other patients, or whether all patients with this mutation will have similar experiences. The patient was already 18 years old when diagnosed, so we don’t have complete information about her early childhood symptoms. Additionally, the attempted treatment with bile acid sequestrant was discontinued, so we don’t have long-term data on whether continued use might have eventually helped. More research with multiple patients is needed to understand the full spectrum of this condition.

The Bottom Line

If you have unexplained fat-soluble vitamin deficiencies that haven’t been explained by standard testing, ask your doctor about genetic testing—it may reveal a rare genetic cause. If you’re diagnosed with SLC10A2 deficiency, work closely with your doctor to monitor your vitamin levels and adjust supplementation as needed. Current standard treatments (like bile acid sequestrants) may not work for everyone with this condition, so personalized treatment plans are important. Confidence level: Low to moderate, as this is based on a single case.

This finding is most relevant to people with unexplained fat-soluble vitamin deficiencies, their families, and healthcare providers who care for patients with absorption problems. People with diagnosed celiac disease, cystic fibrosis, or other known causes of vitamin malabsorption should continue following their established treatment plans. The general population doesn’t need to be concerned about this rare genetic condition unless they have unexplained vitamin deficiencies.

If someone has this genetic condition, vitamin deficiency symptoms could develop over months to years depending on how much supplementation they receive. Once diagnosed and properly supplemented, symptoms can be managed, though the underlying genetic condition is permanent. The timeline for genetic testing results is typically 4-8 weeks after the test is ordered.

Want to Apply This Research?

  • If you have fat-soluble vitamin deficiencies, track your vitamin supplement doses (A, D, E, K) daily and note any symptoms like fatigue, bone pain, or vision changes. Record these in your health app to share with your doctor at appointments.
  • Set daily reminders to take your prescribed vitamin supplements at the same time each day. Use your app to log when you take them and note any side effects or improvements you notice. This helps ensure consistent supplementation and provides data for your doctor.
  • Schedule regular blood tests (every 3-6 months) to check your vitamin levels, and log the results in your app. Track any new symptoms or changes in how you feel. Share this data with your healthcare provider to adjust supplementation doses if needed.

This case report describes a single patient with a rare genetic condition. It is not medical advice. If you suspect you have fat-soluble vitamin deficiencies or absorption problems, consult with a qualified healthcare provider for proper evaluation and treatment. Genetic testing should only be performed under medical supervision. Do not start, stop, or change any medications or supplements without discussing with your doctor first. This information is educational and should not replace professional medical diagnosis or treatment.