Selective IgM deficiency and 22q11.2 deletion syndrome

Area of Science:

• Immunology
• Genetics
• Pediatrics

Background:

• 22q11.2 deletion syndrome is a common chromosomal disorder with variable symptoms and immune defects.
• Selective IgA deficiency is observed in up to 13% of patients, while selective IgM deficiency is rare.
• Previous reports documented only one patient with 22q11.2 deletion and IgM deficiency.

Observation:

• This study describes two additional pediatric patients diagnosed with 22q11.2 deletion syndrome and concurrent selective IgM deficiency.
• Both patients presented with recurrent sinopulmonary infections, otitis media, and developmental issues.
• Laboratory results showed significantly low IgM levels with normal IgA and IgG, and protective antibody titers.

Findings:

• The study highlights a potential association between 22q11.2 deletion syndrome and selective IgM deficiency.
• Clinical manifestations in these patients included recurrent infections, velopharyngeal insufficiency, and developmental delays.
• Normal lymphocyte counts and protective antibody responses suggest a specific defect in IgM production or regulation.

Implications:

• Genetic testing for 22q11.2 deletion should be considered in individuals presenting with selective IgM deficiency.
• Early diagnosis of 22q11.2 deletion syndrome can facilitate timely management of associated immunologic and clinical issues.
• This finding expands the known spectrum of immunologic abnormalities in 22q11.2 deletion syndrome.