Combined Immunodeficiency Due To Dock8 Deficiency

Combined immunodeficiency due to dedicator of cytokinesis 8 protein (DOCK8) deficiency is a form of T and B cell immunodeficiency characterized by recurrent cutaneous viral infections, susceptibility to cancer and elevated serum levels of immunoglobulin E (IgE).

Epidemiology

Prevalence is unknown. To date, 11 patients in eight families have been reported.

Clinical description

Patients present in childhood with symptoms including atopic dermatitis, severe food and environmental allergies, asthma, recurrent upper and lower respiratory tract infections including otitis media, recurrent sinusitis, bronchitis and pneumonia, and extensive cutaneous viral and bacterial infections including superficial, often ulcerating herpes simplex virus infections, flat and verrucous warts, molluscom contagiosum infections, S. aureus skin infections or abscesses, mucosal or nail candidiasis and otitis externa. Patients with long-term herpes simplex virus infections, human papillomavirus infections or molluscom contagiosum have developed vulvar, facial and anal squamous cell dysplasia and carcinoma. The neurologic, vasculitic and autoimmune symptoms associated with autosomal dominant hyper IgE syndrome due to mutations in STAT3 (see this term), are not observed.

Etiology

CID due to DOCK8 deficiency is caused by homozygous or compound heterozygous deletions and point mutations in the DOCK8 gene (9p24), which leads to an absence of DOCK8 protein in lymphocytes, resulting in low absolute T and B lymphocyte counts, mild-to-moderate eosinophilia and very high levels of serum IgE.

Genetic counseling

Transmission is autosomal recessive.