Incidental diagnosis of leukocyte adhesion deficiency type II following ABO typing

Individuals with the Bombay phenotype (Oh) in the ABO blood group system do not express the H, A, and B antigens but have no clinical symptoms. Bombay phenotype with clinical symptoms has been described in leukocyte adhesion deficiency type II (LAD II), a fucosylation disorder caused by mutations in SLC35C1. Only few LAD II patients have been described so far. Here we describe an additional patient, a 22-year old male, born to unrelated parents, presenting with inflammatory skin disease, periodontitis, growth, and mental retardation, admitted to the department of dentistry for treatment under general anesthesia. Pre-operative routine investigations revealed the presence of the Bombay phenotype (Oh). Genomic sequencing identified two novel triplet deletions of the SLC35C1 gene. Functional investigations confirmed the diagnosis of LAD II. Therapy with oral fucose led to the disappearance of the chronic skin infections and improvements in behavior and attention span. •We report the incidental diagnosis of leukocyte adhesion deficiency type II following ABO typing.•Preoperative blood group serology on the occasion of dental treatment under general anesthesia revealed a Bombay phenotype.•Sequencing revealed novel compound heterozygous mutations in SLC35C1 [c.247_249delGTG] + [c.177_179delTAA].•L-fucose therapy led to considerable clinical improvement of chronically inflamed skin and mental status.•Phenotyping of the H antigen may accelerate the diagnosis of leukocyte adhesion deficiency type II.