[Syndrome associating: osteopetrosis, tubular acidosis, mental retardation and cerebral calcifications due to carbonic anhydrase II deficiency. Apropos of 3 cases in the siblings].

Three new cases of a syndrome including osteopetrosis, tubular acidosis, mental retardation and cerebral calcifications are reported in the same sibship. This rare syndrome has an autosomal recessive inheritance and is due to carbonic anhydrase II deficiency. Fractures and mild sensorial manifestations were noticed in 2 cases. Mental deficiency and otitis were present in the 3 cases. Blood count and phosphocalcic metabolites were normal. A proximal tubular acidosis was present in each case. The radiological features were specific: cerebral calcifications were present in all cases since the age of 2 1/2 years; osteocondensation and bone modeling were predominant in long bones metaphyses. Alcalinization improved the height growth.