Overview
Disorders of vitamin D metabolism are a group of rare genetic conditions that affect how your body processes vitamin D. Vitamin D is essential for building and maintaining strong bones because it helps your body absorb calcium and phosphorus from food. When the body cannot properly activate or use vitamin D due to a genetic defect, it leads to weak and soft bones, a condition known as rickets in children and osteomalacia in adults. These disorders include several subtypes. Vitamin D-dependent rickets type 1A (VDDR1A) is caused by a deficiency of the enzyme that converts vitamin D into its active form (calcitriol) in the kidneys. Vitamin D-dependent rickets type 1B involves a different enzyme earlier in the activation pathway. Vitamin D-dependent rickets type 2A (also called hereditary vitamin D-resistant rickets) occurs when the body's cells cannot respond properly to active vitamin D, even when levels are normal. Type 2B is similar but involves a different mechanism of resistance. Key symptoms include bowed legs, poor growth, muscle weakness, bone pain, dental problems, and in some forms, hair loss. These conditions typically appear in infancy or early childhood. Treatment depends on the specific type and may include high doses of active vitamin D (calcitriol) and calcium supplements. With early diagnosis and proper treatment, many patients can achieve significant improvement in bone health and growth, though lifelong management is usually required.
Key symptoms:
Bowed legs or knock kneesPoor growth and short statureMuscle weaknessBone pain and tendernessDelayed walking or waddling gaitSoft skull bones in infantsWidening of the wrists and anklesDental problems such as delayed teeth or weak enamelFrequent bone fracturesHair loss (in some types, can be partial or complete)Seizures due to low calcium levelsIrritability in infantsFailure to thriveSkeletal deformities of the chest or spine
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Infantile
Begins in infancy, roughly 1 month to 2 years old
FDA & Trial Timeline
10 eventsAssiut University
Khyber Teaching Hospital — NA
University of Miami — PHASE4
Mansoura University
Universidad Autonoma del Estado de Mexico — NA
Ottawa Hospital Research Institute — NA
Héctor Iván Saldívar Cerón — NA
Huazhong University of Science and Technology — NA
Procare Health Iberia S.L.
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Disorders of vitamin D metabolism.
15 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Disorders of vitamin D metabolism.
Community
No community posts yet. Be the first to share your experience with Disorders of vitamin D metabolism.
Start the conversation →Latest news about Disorders of vitamin D metabolism
Disease timeline:
New recruiting trial: A Household-Based Dietary Intervention Study of Vitamin D Fortified Bread in Irish Families
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: Exercise Training and Vitamin D Metabolism
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: VitD3 Supplementation in Patients With Multiple Myeloma
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: Vitamin D and Health Status of British African-Caribbean Women
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: Effects of Vitamin D3 and Yeast Beta-Glucan Supplementation on Glycemic Control and Cardiovascular Disease Risk in Patients With Type 2 Diabetes
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: A First-in-human Study of KK8123 in Adults With X-linked Hypophosphatemia
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: A Natural History Study of Bone and Mineral Disorders
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: Total Post-thyroidectomy Hypocalcemia After Preoperative Cholecalciferol Supplementation
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: Effect of Micronutrient Supplementation on Nerve Conduction Velocity in T1D- RCT
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
New recruiting trial: Vitamin D for Critically Traumatic Patients
A new clinical trial is recruiting patients for Disorders of vitamin D metabolism
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.Which specific type of vitamin D metabolism disorder does my child have, and what gene is affected?,What are the target blood calcium and vitamin D levels we should aim for with treatment?,How often will blood tests and bone X-rays be needed to monitor progress?,What are the signs that the medication dose needs to be adjusted?,Are there risks of kidney damage from long-term calcitriol and calcium treatment, and how will this be monitored?,Will my child's growth catch up with treatment, or should we expect some lasting effects?,What is the chance that future children could have the same condition, and should other family members be tested?
Common questions about Disorders of vitamin D metabolism
What is Disorders of vitamin D metabolism?
Disorders of vitamin D metabolism are a group of rare genetic conditions that affect how your body processes vitamin D. Vitamin D is essential for building and maintaining strong bones because it helps your body absorb calcium and phosphorus from food. When the body cannot properly activate or use vitamin D due to a genetic defect, it leads to weak and soft bones, a condition known as rickets in children and osteomalacia in adults. These disorders include several subtypes. Vitamin D-dependent rickets type 1A (VDDR1A) is caused by a deficiency of the enzyme that converts vitamin D into its act
How is Disorders of vitamin D metabolism inherited?
Disorders of vitamin D metabolism follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Disorders of vitamin D metabolism typically begin?
Typical onset of Disorders of vitamin D metabolism is infantile. Age of onset can vary across affected individuals.
Are there clinical trials for Disorders of vitamin D metabolism?
Yes — 15 recruiting clinical trials are currently listed for Disorders of vitamin D metabolism on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Disorders of vitamin D metabolism?
25 specialists and care centers treating Disorders of vitamin D metabolism are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.