Which condition can be confused with transient hypogammaglobulinemia in infancy?

Transient hypogammaglobulinemia of infancy is a condition characterized by a temporary decrease in immunoglobulin levels, particularly IgG, in otherwise healthy infants. This condition usually resolves as the infant matures and their immune system develops, often by 12 to 15 months of age.

Bruton agammaglobulinemia, also known as X-linked agammaglobulinemia, presents similarly as it involves a significant decrease or absence of immunoglobulins due to a genetic mutation affecting B-cell development. In this condition, infants may present with recurrent infections due to the lack of functional antibodies and typically present with very low or undetectable levels of immunoglobulins. Unlike transient hypogammaglobulinemia, Bruton agammaglobulinemia is a permanent condition that does not resolve with age and also typically manifests much earlier in life.

The ability to confuse transient hypogammaglobulinemia with Bruton agammaglobulinemia arises from the overlapping presentation of low immunoglobulin levels. However, the key distinction lies in the permanence and genetic basis of Bruton agammaglobulinemia versus the transient nature of hypogammaglobul