Which of the following is NOT a known symptom associated with IgA deficiency?

The correct answer indicates that weight gain is not a known symptom associated with IgA deficiency. Immunoglobulin A (IgA) is an antibody that plays a crucial role in mucosal immunity. Individuals with IgA deficiency are more susceptible to infections, particularly in the respiratory tract and gastrointestinal system, leading to symptoms such as recurrent respiratory infections and diarrhea.

Keratinization of the cornea is also linked to IgA deficiency due to the implications of mucosal immunity on the ocular surface, which can lead to dryness and abnormal corneal changes. These conditions highlight the importance of IgA in maintaining a healthy immune barrier in mucosal tissues.

Weight gain, however, is not typically associated with IgA deficiency. If anything, the recurrent infections and potential gastrointestinal issues could lead to weight loss or difficulties in gaining weight, rather than the opposite. Thus, it stands apart from the other symptoms listed and is the correct choice for the question.