A 4-month-old male presents with recurrent oral thrush, chronic diarrhea, and recurrent severe respiratory infections. Vital signs show HR 128/min, RR 32/min, temperature 37.2°C, SpO2 94% on room air. Laboratory studies reveal profound lymphopenia (absolute lymphocyte count 800/μL) affecting both T and B cells, with normal immunoglobulin levels. Chest X-ray shows interstitial pneumonia without thymic shadow. He has received no vaccinations. Which enzyme deficiency most likely explains this immunodeficiency?
- A)Dihydropteridine reductase
- B)Hypoxanthine guanine phosphoribosyltransferase
- C)Ornithine transcarbamylase
- D)Adenosine deaminaseGABARITO
- E)Galactose 1 phosphate uridyltransferase
Explicação
This infant has adenosine deaminase deficiency, a cause of severe combined immunodeficiency. Accumulation of deoxyadenosine is toxic to lymphocytes, leading to failure of both cellular and humoral immunity. Early recurrent infections with opportunistic organis... Ver explicação completa e trilha adaptativa →