NCIt definition : A sub-type of autosomal recessive osteopetrosis caused by mutation(s) in the TCIRG1
gene on chromosome 11q13, encoding the osteoclast-specific (alpha 3) subunit of the
vacuolar proton pump. It is characterized by macrocephaly, frontal bossing, nystagmus,
optic atrophy, blindness, deafness, and facial palsy.;