title: Somatic revertant mosaicism in a patient with leukocyte adhesion deficiency type 1.
abstract: Leukocyte adhesion deficiency type 1 (LAD-1) is an autosomal recessive disorder caused by mutations in the ITGB2 (CD18) gene and characterized by recurrent severe infections, impaired pus formation, and defective wound healing. We describe an unusual case of severe phenotypic LAD-1 presenting with somatic mosaicism. The patient is a compound heterozygote bearing 2 different frameshift mutations that abrogate protein expression. However, CD18 expression was detected in a small proportion of T cells but was undetectable in granulocytes, monocytes, B cells, and natural killer (NK) cells. The T cells were not of maternal origin, lacked the paternal mutation, and showed a selective advantage in vivo. Molecular analysis using sorted CD18+ cells revealed them to be derived from a single CD8+ T cell carrying T-cell receptor VB22. These findings suggest that spontaneous in vivo reversion was responsible for the somatic mosaicism in our patient.
authors.affiliation: Department of Pediatrics, Graduate School of Medical Science, Kanazawa University, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Tone
authors.forename: Taizo
authors.initials: T
authors.lastname: Wada
authors.forename: Fumie
authors.initials: F
authors.lastname: Shibata
authors.forename: Tomoko
authors.initials: T
authors.lastname: Toma
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hashida
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Kasahara
authors.forename: Shoichi
authors.initials: S
authors.lastname: Koizumi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yachie
mesh_terms: D018821:CD18 Antigens / Q000032:analysis / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry; D016368:Frameshift Mutation; D006579:Heterozygote; D006801:Humans; D007231:Infant, Newborn; D018370:Leukocyte-Adhesion Deficiency Syndrome / Q000235:genetics*; D009030:Mosaicism
chemical_list: D018821:CD18 Antigens