16th February 2024

A 32-year-old male presented to his GP for blood tests and found undetectable levels of IgA antibodies

A 32-year-old male presented to his GP for blood tests and found undetectable levels of IgA antibodies but normal levels of IgM and IgG antibodies. He notes his mother has had recurrent sinusitis and upper respiratory tract infections, necessitating prophylactic antibiotics.

Which of the following conditions likely explains his test findings?

Select the SINGLE most appropriate option from the list below. Select ONE option only.