Mutation spectra of the ITGB2 gene in Iranian families with leukocyte adhesion deficiency type 1

Leukocyte adhesion deficiency type 1 (LAD1) is an autosomal recessive disorder clinically characterized by severe, recurrent bacterial infections, impaired pus formation and wound healing. It is caused by mutation in the ITGB2 gene, encoding the β₂ integrin subunit of the leukocyte adhesion cell molecule. This study aimed to identify disease causing mutations in 19 consanguineous families diagnosed with LAD1.Blood samples were collected after informed and written consent was obtained. Genomic DNA was extracted from peripheral blood of patients and their parents. PCR amplification of the ITGB2 gene was done using specific primers followed by sequencing for mutation detection.A total number of 14 alterations scattered throughout the ITGB2 gene were ascertained in which 10 mutations were previously reported, including c.329−6C>A, c.382G>T, c.715G>A, c.843delC, c.897+1G>A, c.1062A>T, c.1143delC, c.1877+2T>C, c.1907delA and c.2147G>C. Four novel likely pathogenic mutations consisting of c.576dupC (Asn193GlnfsX72), c.706G>A (Gly236Arg), c.897+1G>T and c.1030G>T (Glu344¹), were identified. The majority of these mutations were located in exon six, suggesting this exon as a hotspot region probably.This study emphasis on allelic heterogeneity of the ITGB2 gene in Iranian patients diagnosed with LAD1. Our results suggest that every population should develop a mutation database for rare genetic disorders to take advantage in genetic counseling clinic as well as genetic testing for rapid diagnostic purposes.