A 25-day-old male is brought to the physician due to seizures, rigidity and frequent viral infections. Physical examination reveals a neonate with cyanosis in the lower extremities. The most likely…

The correct answer is D. deletion in chromosome 22q11.2. The patient most likely has thymic aplasia which is also known as DiGeorge syndrome. It is caused by a deletion in chromosome 22q11.2 which leads to failure of the third and fourth pharyngeal pouches to develop. The features of DiGeorge syndrome include conotruncal cardiac…

Abnormal Processes

Question

A 25-day-old male is brought to the physician due to seizures, rigidity and frequent viral infections. Physical examination reveals a neonate with cyanosis in the lower extremities. The most likely cause of these findings is a

Options

Adefect in the IL-2R gamma chain
Bdefect in the lysosomal trafficking regulation gene
Cdefect in the tyrosinase kinase gene
Ddeletion in chromosome 22q11.2
Emutation in the STAT3 gene

How the community answered

(32 responses)

A
6% (2)
B
3% (1)
C
16% (5)
D
72% (23)
E
3% (1)

Explanation

The patient most likely has thymic aplasia which is also known as DiGeorge syndrome. It is caused by a deletion in chromosome 22q11.2 which leads to failure of the third and fourth pharyngeal pouches to develop. The features of DiGeorge syndrome include conotruncal cardiac anomalies such as tetralogy of Fallot and truncus arteriosus, an absent thymus gland which leads to T-cell deficiency and frequent viral infections, and hypocalcemia due to a hypoplastic parathyroid. The congenital heart defect may lead to cyanosis and the hypocalcemia can present with seizures and tetany. Laboratory findings include decreased T cell levels, decreased parathyroid hormone, decreased calcium levels and a thymic shadow on a chest x-ray.

Topics

#DiGeorge syndrome#22q11.2 deletion#thymic aplasia#combined immunodeficiency

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