RESUMO
Autosomal Recessive osteopetrosis [ARO] is a severe bone disease, whose cellular defect is consisting in impaired osteoclast bone resorption, resulting in generalized osteosclerosis and obliteration of marrow. The molecular defect is heterogeneous. 50 per cent of ARO patients show an abnormality in the TCIR1 gene coding for the a3 subunit of vacuolar proton pump that plays a fundamemtal role in acidifying the osteoclast-bone interface. We report a new case with mutation in the TCIRG1 gene. The patient, a 4 months old male infant, presented with exophthalmia, macrocephaly, hepatosplenomegaly, a very severe bone sclerosis,anemia, thrombocytopenia, optic atrophy, with fatal outcome at second year. He has the mutation G11049T in homozygous state in the TCIRG1 gene, this mutation is in heterozygous state in the parents. Prenatal diagnosis was carried out in the mother by amniocentesis performed at 16 weeks of second gestation. The fetal DMA analysis showed that same mutation were present in heterozygous state. A healthy baby with no clinical, radiological or abnormalities was delivered