Reference entry for the CA2-related condition, including the synonym carbonic anhydrase II deficiency.
Resources and research
Only original sources are linked. This site does not turn those sources into a diagnosis, and reading the source itself still matters.
Trusted medical sources
Gene entry for the enzyme carbonic anhydrase II.
Rare-disease page describing the condition, its link to CA2, and synonyms such as Guibaud-Vainsel syndrome.
Official gene record from the National Center for Biotechnology Information.
Disease summary linking mixed renal tubular acidosis to carbonic anhydrase II deficiency and CA2.
Research and scientific studies
The paper that identified carbonic anhydrase II deficiency as the basis of the syndrome in the first reported family. DOI
A multi-family study supporting enzyme deficiency as the enzymatic basis of the syndrome.
Molecular description in the American family in which the association was first recognized.
Neurologic, neuro-ophthalmologic, and imaging features in a group sharing the same descriptive mutation.
A case report linking a CA2 deletion to the clinical diagnosis and describing enamel involvement in that person.
Plain-language starting points
A shorter reference page than journal articles, useful before reading the studies.
A saved search of indexed papers on carbonic anhydrase II deficiency and CA2. This site does not select a treatment from those results.
For students, researchers and healthcare professionals
Academic Medical References & Research
A research library focused on carbonic anhydrase II deficiency and CA2. Summaries here are original and short. Official titles stay in the language of publication. Case reports and experimental studies are not presented as proven treatment.
Academic library last reviewed: September 2026
This library gathers sources that were checked and core related references. It is not a final index of every scientific paper. Scientific databases change continuously, so a fresh search is advised before a systematic review or academic study.
Download every medical reference, each title with its own links only:
References shown in the bibliography: 0
Start here
ReviewRecommended Review
Carbonic anhydrase II deficiency.
A recent clinical review of carbonic anhydrase II deficiency and its association with osteopetrosis, renal tubular acidosis, and cerebral calcification.
Foundational study
Carbonic anhydrase II deficiency identified as the primary defect in the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification.
The paper that identified the enzyme deficiency itself as the primary defect, in the family first described with the syndrome.
Family series
Carbonic anhydrase II deficiency in 12 families with the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification.
A study of 12 families supporting enzyme deficiency as the shared enzymatic basis of the syndrome.
Molecular study
Carbonic anhydrase II deficiency syndrome in a Belgian family is caused by a point mutation at an invariant histidine residue (107 His----Tyr): complete structure of the normal human CA II gene.
Reports a point change at histidine 107 in a Belgian family, and the structure of the normal human CA2 gene.
Molecular study
Molecular basis of human carbonic anhydrase II deficiency.
Describes the molecular basis in the American family in which the enzyme association was first recognized.
Molecular study
Carbonic anhydrase II deficiency syndrome (osteopetrosis with renal tubular acidosis and brain calcification): novel mutations in CA2 identified by direct sequencing expand the opportunity for genotype-phenotype correlation.
Identified additional CA2 changes and widened the chance to compare genotype with the clinical picture.
Clinical series
The neurology of carbonic anhydrase type II deficiency syndrome.
Neurologic, neuro-ophthalmologic, and imaging findings in a Saudi group homozygous for the Arabic mutation.
Genetic and medical databases
Disease
OMIM
Disease entry for OPTB3, synonyms, and inheritance.
Gene
OMIM
Gene entry for CA2, which encodes the enzyme.
Gene
NCBI Gene
Official gene record, with links to sequence and citations.
Gene
HGNC
Approved gene symbol and aliases.
Gene
Ensembl
Gene coordinates, transcripts, and variants in the genome build.
Protein
UniProt
Protein sequence, function, and reviewed variant sites.
Disease
Orphanet
Rare-disease page and synonyms such as Guibaud-Vainsel syndrome.
Phenotype
MedGen
Disease concept record linking the phenotype to the gene and sources.
Disease
GARD
Rare-disease summary for clinicians and families, with links outward.
Variant
ClinVar
Submitted CA2 variants and interpretations, including those linked to osteopetrosis with renal tubular acidosis.
Gene
ClinGen / GenCC
The CA2–autosomal recessive osteopetrosis 3 relationship is classified Definitive as of 10 June 2024. That is a gene-disease validity class, not a judgment on every variant.
Testing
NCBI GTR
Registered genetic tests for CA2. A listed test is not a recommendation of that laboratory.
Variant
LOVD
Shared variant database, to be read beside ClinVar rather than instead of it.
Protein
Human Protein Atlas
Protein expression across tissues in the atlas, not an individual diagnosis.
Academic bibliography
History and discovery
Foundational report
Osteopetrosis and renal tubular acidosis. 2 cases of this association in a sibship.
One of the earliest reports of osteopetrosis with renal tubular acidosis in siblings, before the enzyme defect was identified.
Foundational report
Osteopetrosis associated with proximal and distal tubular acidosis.
An early report linking osteopetrosis with proximal and distal tubular acidosis, later used as one of the syndrome names.
Family series
Osteopetrosis, renal tubular acidosis and basal ganglia calcification in three sisters.
Describes three sisters with osteopetrosis, renal tubular acidosis, and basal ganglia calcification, before the enzyme was identified.
Foundational study
Carbonic anhydrase II deficiency identified as the primary defect in the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification.
The paper that identified the enzyme deficiency itself as the primary defect, in the family first described with the syndrome.
Family series
Carbonic anhydrase II deficiency in 12 families with the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification.
A study of 12 families supporting enzyme deficiency as the shared enzymatic basis of the syndrome.
Imaging study
Intracranial calcification in children with osteopetrosis caused by carbonic anhydrase II deficiency.
Describes intracranial calcification in children with osteopetrosis linked to the enzyme deficiency. This is an imaging study, not a treatment report.
Diagnostic method
Carbonic anhydrase II deficiency: diagnosis and carrier detection using differential enzyme inhibition and inactivation.
An enzyme method used at the time to diagnose the deficiency and detect carriers, before genetic testing was widely used.
Physiologic study
Transfusion of carbonic anhydrase-replete erythrocytes fails to correct the acidification defect in the syndrome of osteopetrosis, renal tubular acidosis, and cerebral calcification (carbonic anhydrase-II deficiency).
Transfusion of enzyme-replete red cells did not correct the acidification defect. This is a study result, not a treatment recommendation.
Basic science
Carbonic anhydrase isozymes IV and II in urinary membranes from carbonic anhydrase II-deficient patients.
Examines CA IV and CA II in urinary membranes from people with CA II deficiency. This is basic localization work, not a treatment study.
Genetics and mutations
Molecular study
Carbonic anhydrase II deficiency syndrome in a Belgian family is caused by a point mutation at an invariant histidine residue (107 His----Tyr): complete structure of the normal human CA II gene.
Reports a point change at histidine 107 in a Belgian family, and the structure of the normal human CA2 gene.
Molecular study
Molecular basis of human carbonic anhydrase II deficiency.
Describes the molecular basis in the American family in which the enzyme association was first recognized.
Molecular study
A splice junction mutation in intron 2 of the carbonic anhydrase II gene of osteopetrosis patients from Arabic countries.
Describes the intron 2 splice-junction change in patients from Arabic countries. This is the Arabic mutation, not a label for a Saudi-only change.
Case series
Carbonic anhydrase II deficiency in three unrelated Japanese patients.
Three unrelated Japanese patients, showing that the enzyme deficiency is not limited to one population.
Molecular study
A unique mutation underlying carbonic anhydrase II deficiency syndrome in patients of Arab descent.
Linked one CA2 change to the deficiency syndrome in patients of Arab descent.
Molecular study
Carbonic anhydrase II deficiency: single-base deletion in exon 7 is the predominant mutation in Caribbean Hispanic patients.
A single-base deletion in exon 7 was the most frequent change in a Caribbean Hispanic group, and it is distinct from the Arabic mutation.
Clinical and molecular study
Carbonic anhydrase II deficiency syndrome--clinico-pathological, biochemical and molecular studies.
Brings together clinical, pathologic, biochemical, and molecular observations on the syndrome, and is not a treatment protocol.
Molecular study
Clinical and molecular heterogeneity in carbonic anhydrase II deficiency and prenatal diagnosis in an Italian family.
Shows clinical and molecular differences, and reports prenatal diagnosis in one Italian family.
Molecular study
Carbonic anhydrase II deficiency syndrome (osteopetrosis with renal tubular acidosis and brain calcification): novel mutations in CA2 identified by direct sequencing expand the opportunity for genotype-phenotype correlation.
Identified additional CA2 changes and widened the chance to compare genotype with the clinical picture.
Case reportCase Report
Carbonic anhydrase II deficiency: report of a novel mutation.
One Saudi compound-heterozygous case, with a novel change beside the Arabic mutation. It should not be treated as a common mutation.
Family reportCase Report
A novel homozygous nonsense mutation in the CA2 gene (c.368G>A, p.W123X) linked to carbonic anhydrase II deficiency syndrome in a Chinese family.
A Chinese family homozygous for the stop change c.368G>A. This is a family report, not a prevalence survey.
Case reportCase Report
Carbonic anhydrase II deficiency syndrome with amelogenesis imperfecta linked to a homozygous CA2 deletion.
One person with the enzyme deficiency and amelogenesis imperfecta, linked to a homozygous CA2 deletion. It does not show that every affected person has the same dental finding.
Renal and renal tubular acidosis
Physiologic study
Positive renal response to intravenous acetazolamide in patients with carbonic anhydrase II deficiency.
Measured a renal response after intravenous acetazolamide. This is a physiologic observation, not evidence of an established clinical treatment.
Case series
Nephrocalcinosis and urolithiasis in carbonic anhydrase II deficiency syndrome.
Describes nephrocalcinosis and urinary stones in people with the syndrome. It documents a renal complication, not a proven treatment.
Case reportCase Report
Paralysis Episodes in Carbonic Anhydrase II Deficiency.
One person with paralysis episodes that were initially misdiagnosed. Indexed affiliation: Riyadh Armed Forces Hospital. Not a typical picture for every affected person.
Clinical reportCase Report
Cerebral calcification, osteopetrosis and renal tubular acidosis: is it carbonic anhydrase-II deficiency?
Discusses cerebral calcification, osteopetrosis, and renal tubular acidosis and asks whether this is CA II deficiency. The title is a question, so this site does not treat it as a confirmed molecular diagnosis.
Case reportCase Report
Marble brain disease: a rare cause of renal tubular acidosis.
Presents marble brain disease as a rare cause of renal tubular acidosis. A case report, not a treatment review.
Neurology and brain imaging
Clinical series
The neurology of carbonic anhydrase type II deficiency syndrome.
Neurologic, neuro-ophthalmologic, and imaging findings in a Saudi group homozygous for the Arabic mutation.
Retrospective imaging study
The correlation of intracranial parenchymal calcium score and the severity of neurological clinical presentation in carbonic anhydrase deficiency type 2.
A chart review of ten children diagnosed at King Saud University Medical City from 2015 to 2022. PubMed dates it February 2025. It compared an intracranial calcium score with neurologic findings and did not find a correlation that would support using the score for prognosis. Not a treatment study.
Bone and treatment reports
ReviewRecommended Review
Carbonic anhydrase II deficiency.
A recent clinical review of carbonic anhydrase II deficiency and its association with osteopetrosis, renal tubular acidosis, and cerebral calcification.
Review
Carbonic anhydrase II deficiency.
An earlier orthopaedic review of the syndrome, useful as historical context beside the 2023 Bone review.
Case reportExperimentalCase Report
Bone marrow transplantation corrects osteopetrosis in the carbonic anhydrase II deficiency syndrome.
Reports that bone marrow transplantation corrected osteopetrosis in the deficiency syndrome. A published case result, not an established general treatment, and it does not remove the need for specialist review of acidosis and calcification.
Case reportExperimentalCase Report
Allogenic hematopoietic stem cell transplantation in an Iranian patient with osteopetrosis caused by carbonic anhydrase II deficiency: A case report.
One Iranian case report of allogeneic hematopoietic stem-cell transplantation. An individual experimental result, not a general standard of care.
Basic science and protein
Basic scienceBasic / preclinical
N-ethyl-N-nitrosourea-induced null mutation at the mouse Car-2 locus: an animal model for human carbonic anhydrase II deficiency syndrome.
A mouse model with a null change at the corresponding locus. Basic animal research, not a human clinical result.
Basic scienceBasic / preclinical
Thermodynamic interrogation of a folding disease. Mutant mapping of position 107 in human carbonic anhydrase II linked to marble brain disease.
Biophysical measurements of protein folding at position 107, linked to marble brain disease. Preclinical protein research, not a treatment.
Basic scienceBasic / preclinical
Small-molecule suppression of misfolding of mutated human carbonic anhydrase II linked to marble brain disease.
Tested small molecules on misfolding of the mutated protein in the laboratory. Preclinical research, not an established clinical treatment.
Saudi Arabia
Family series
Marble brain disease: recessive osteopetrosis, renal tubular acidosis and cerebral calcification in three Saudi Arabian families.
An early description of children from three Saudi families at King Faisal Specialist Hospital and Research Centre, Riyadh, before the enzyme was identified.
Case series
Carbonic anhydrase II deficiency syndrome: recessive osteopetrosis with renal tubular acidosis and cerebral calcification.
New Saudi cases, with enzyme deficiency measured in some family members.
Case reportCase Report
The syndrome of osteopetrosis, renal acidosis and cerebral calcification in two sisters.
Two Saudi sisters with the syndrome. The available abstract does not establish the city, so it is not stated here.
Follow-up series
Long-term follow up of carbonic anhydrase II deficiency syndrome.
Follow-up of 35 Saudi children at King Faisal Specialist Hospital and Research Centre, Riyadh, since 1979. These counts should not be added to other studies as a national total.
Case reportCase Report
Marble brain disease in two Saudi Arabian siblings.
Two siblings from Asir Central Hospital. The report describes growth improvement after acidosis treatment in these two children only.
Case series
Carbonic anhydrase II deficiency syndrome: a report of 18 new Saudi Arabian cases.
Eighteen children followed at Al-Rass General Hospital from 2004 to 2008. Diagnosis in the series was clinical, radiographic, and biochemical. No PubMed record was found, so only the publisher DOI is linked. These cases should not be added to other series.
Incidence study
Incidence and patterns of inborn errors of metabolism in the Eastern Province of Saudi Arabia, 1983-2008.
Three CA II cases among 165,530 births at Saudi Aramco facilities. The listed rate applies only to that setting, not nationally.
Case reportCase Report
Carbonic Anhydrase II Deficiency in a Saudi Woman.
One Saudi woman with the classic triad, homozygous for c.232+1G>A. The hospital is not established in the abstract available here.
Case reportCase Report
Carbonic Anhydrase II Deficiency: Unusual Presentation of the Arabic Mutation. A Case Report.
One child at King Fahad Medical City and King Saud Medical City, with the Arabic mutation confirmed. A case report of an unusual presentation, not a treatment series.
No references match this search or filter.
Academic search terms
Choose a phrase to search this library and to open current database searches.