Carbonic anhydrase 2
Carbonic anhydrase 2 is an enzyme found predominantly in the lumen of renal tubules where it plays an essential role in proton secretion. If defective, mixed type renal tubular acidosis results. The enzyme has an additional function in bone turnover where a defect causes osteopetrosis.
Expression
Carbonic anhydrase 2 is predominantly found in kidney and bone.
Phenotype
If the function of this enzyme is deficient renal excretion of protons is impaired. Because the enzyme is essential in proximal and distal tubules a mixed type renal tubular acidosis results. The characteristic bone symptom is osteopetrosis.
Gene Regulation
In kidney, it acts intraluminal in both proximal and distal tubules, where it facilitates proton secretion and bicarbonate reabsorption. In bone turnover the enzyme is involved in bone mineral resorption.
Test Strategy
Carbonic anhydrase activity can be measured, but the method appears clumsy nowadays.[1]
Interpretation
Interpretation of negativ mutational analysis should take into account the possibility of phenocopy caused by concurrent mutations of TCIRG1 and ATP6V1B1 genes.[2]
Genetests:
| Clinic | Method | Carrier testing |
| Turnaround | 5 | |
| Specimen type | genomic DNA |
| Clinic | Method | Genomic sequencing of the entire coding region |
| Turnaround | 20 | |
| Specimen type | genomic DNA |
| Clinic | Method | Massive parallel sequencing |
| Turnaround | 25 | |
| Specimen type | genomic DNA |
Related Diseases:
References:
| 1. |
Borthwick KJ et al. (2003) A phenocopy of CAII deficiency: a novel genetic explanation for inherited infantile osteopetrosis with distal renal tubular acidosis. [^] |
| 2. |
MAREN TH et al. (1960) A simplified micromethod for the determination of carbonic anhydrase and its inhibitors. [^] |
| 3. |
Lotan D et al. (2006) Clinical and molecular findings in a family with the carbonic anhydrase II deficiency syndrome. [^] |
