NCIt definition : A rare immunodeficiency with an autosomal recessive pattern of inheritance. It is
caused by mutation in the ITGB2 gene on chromosome 21 which codes for the beta subunit
of beta-2 integrin (CD18). The mutation results in significantly reduced or absent
expression of CD18 on the surface of leukocytes which impairs their ability to migrate
and interact with antigens. Initial clinical signs include omphalitis and delayed
separation of the umbilical cord. The clinical course is marked by recurrent bacterial
and fungal infection without pus formation. In instances where there is 1% expression
of CD18, prognosis is dismal with a high likelihood for life-threatening infection
within the first year of life.;