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Osteopetrosis with renal tubular acidosis is a rare disorder characterized by osteopetrosis, renal tubular acidosis (RTA), and neurological disorders related to cerebral calcifications.
Features include very common findings: Osteopetrosis, Renal tubular acidosis, and Abnormal circulating enzyme concentration or activity; and common findings: Basal ganglia calcification, Elevated serum acid phosphatase, Short stature, and Distal renal tubular acidosis and others. 69 total HPO annotations.
Organ System | Phenotype Count | Example Features |
|---|---|---|
Brain and nerves | 9 | Cerebral calcification, Intellectual disability, Global developmental delay |
Eyes | 5 | Optic nerve compression, Visual impairment, Abnormal retinal morphology |
Kidneys and urinary system | 4 | Distal renal tubular acidosis, Renal tubular acidosis, Proximal renal tubular acidosis |
Bones and joints | 4 | Osteopetrosis, Recurrent fractures, Bone marrow hypocellularity |
Blood and immune system | 4 | Low red blood cell count (anemia), Low platelet count (thrombocytopenia), Low blood cell counts (all types) (pancytopenia) |
Head and neck | 4 | Abnormal facial shape, Thick lower lip vermilion, High palate |
Lab test results | 2 | Elevated serum acid phosphatase, Elevated creatine kinase (muscle enzyme) (elevated circulating creatine kinase concentration) |
Growth and development | 2 | Short stature, Failure to thrive |
Digestive system | 2 | Hepatosplenomegaly, Enlarged liver (hepatomegaly) |
Muscles | 2 | Damage to the optic nerve (optic atrophy), Retinal atrophy |
Lungs and breathing | 2 | High blood pressure in lung arteries (pulmonary arterial hypertension), Obstructive sleep apnea |
Ears | 1 | Conductive hearing impairment |
Metabolism | 1 | Metabolic acidosis |
Heart and blood vessels | 1 | High blood pressure in lung arteries (pulmonary arterial hypertension) |
CA2 encodes carbonic anhydrase 2 (260 aa). Catalyzes the reversible hydration of carbon dioxide. Can also hydrate cyanamide to urea. Stimulates the chloride-bicarbonate exchange activity of SLC26A6. Highest expression in Stomach (273.6 TPM) and Colon Transverse (253.3 TPM).
Autosomal recessive osteopetrosis 3 is caused by mutations in the CA2 gene on chromosome 8.
The CA2 protein participates in TGM1:Ca2+, TGM5:Ca2+, ANO5:ANO5:Ca2+, ANO6:ANO6:Ca2+, and Calpain1, Calpain2:Ca2+ pathways.
CA2 is classified as a druggable target (Druggable Genome and Enzyme categories) with score 2.0.
Genetic testing for CA2 is available. Testing is considered confirmatory for diagnosis.
Phenotype severity distribution: 3 very common features, 13 common features.
Estimated prevalence: <1 in 1,000,000 (VERY_RARE).
No clinical trials have been registered for autosomal recessive osteopetrosis 3.
4 publications have been identified in PubMed for autosomal recessive osteopetrosis 3. Research spans Case Report / Case Series (75%) and Basic Science / Preclinical (25%).
AlFaris B (2025). [PMID: 39667299](https://pubmed.ncbi.nlm.nih.gov/39667299/). *Brain & development*. [Basic Science / Preclinical]
Bhandarkar A (2025). [PMID: 40568329](https://pubmed.ncbi.nlm.nih.gov/40568329/). *World journal of nephrology*. [Case Report / Case Series]
Laridi A (2025). [PMID: 40528923](https://pubmed.ncbi.nlm.nih.gov/40528923/). *Radiology case reports*. [Case Report / Case Series]
Shamsian BS (2024). [PMID: 38655726](https://pubmed.ncbi.nlm.nih.gov/38655726/). *Pediatric transplantation*. [Case Report / Case Series]
Data assembled from 7 of 12 sources · Last updated Sep 19, 2026, 11:56 AM UTC
Online Mendelian Inheritance in Man
European rare disease database
Genetic and Rare Diseases Info Center