Rare gross deletion in T-cell immune regulator-1 gene in Iranian family with infantile malignant osteopetrosis

Infantile malignant osteopetrosis (arOP) is an autosomal recessive disorder. Mutations in the T-cell immune regulator 1 (TCIRG1) gene were found as the cause of arOP. We found the first Iranian patient with a rare gross deletion in this gene. The patient was a 5-year-old girl with macrocephaly, facial dysmorphism, blindness, mental retardation, hepatosplenomegaly, pancytopenia, and osteosclerotic changes in the skull and limb. Molecular analysis was performed using reverse transcriptase-polymerase chain reaction for exons 10-19 of the TCIRG1 gene followed by whole gene sequencing. She showed a 275 bp unexpected amplified segment. Sequencing revealed a gross deletion in exons 10-15 transcript region of TCIRG1 that affected codon 389 to 518. Various types of mutations in the TCIRG1 gene in arOP have been reported, however, gross deletions are reported rarely. This gross deletion is the first mutation reported among Iranian patients in this gene. This deletion is also the largest deletion of TCIRG1 gene reported to date.