A mother brings her 1 year old child to the hospital with complaints that he turns blue while breastfeeding. It resolves when he assumes a squatting position. On examination, a cleft palate is seen. Labs show hypocalcemia. Which of the following abnormalities are expected to be seen in the lymphoid organs?

Decreased size of paracoical areas of lymph nodes is expected as this child has DiGeorge Syndrome. DiGeorge Syndrome: Deficient CMI is seen due to aplasia of thymus and hence deficiency of T cells. This leads to paracoical areas of lymph nodes and periaeriolar sheaths of the spleen being reduced in size. B cells are usually not affected. Clinical Features of DiGeorge Syndrome - DiGeorge syndrome is a cellular immunodeficiency disorder caused by the deletion of a small segment of chromosome 22 (22q11) leading to a developmental defect involving the endodermal derivatives of the third and fouh pharyngeal pouches. (Thymus and parathyroid glands) The clinical features can be remembered with the mnemonic - CATCH C - Cardiac defects A - Abnormal facies T - Thymic aplasia C - Cleft palate H - Hypocalcemia Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition