Osteopetrosis with renal tubular acidosis. Carbonic anhydrase II deficiency.
Incidence
It is inherited as autosomal recessive.
Clinical Characteristics
This condition is characterized by physical and developmental retardation, facial appearance characterized by broad face, over hanging forehead, narrow nose, epicantal folds, thin upper lip, poorly developed philtrum, everted lower lip, micrognathia and dental malocclusion. Osteomalacia may occur as well as cranial nerve compression. There is renal tubular acidosis which can be usually proximal but also distal or combined type. There is a hyperchloremic metabolic acidosis and sometimes hypokalemia. There is a deficiency of carbonic anhydrase II and protein levels in red blood cells. Often, there is muscle weakness, failure to thrive, short stature, psychomotor delay and mental subnormality Low levels of carbonic anhydrase in parents and siblings. The main radiological characteristic are osteosclerosis and skeletal modeling defect, fractures and on the CT scan there is cerebral calcification affecting basal ganglia and periventricular white matter. The intracranial calcification can be extensive and easily demonstrable by CT scan and even plain X-rays.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
Clinical and radiological findings. Deficiency of carbonic anhydrase II present in RBCs.