A. Translocation (4%)

B. Mosaicism (1%)

C. Non-disjunction (95%)

D. Chromosomal deletion (0.5%)

A. Chronic leukemia requiring lifelong therapy

B. A benign transient myeloid proliferation resolving within 3 months

C. A lymphoid neoplasm associated with trisomy 18

D. A congenital infection with hepatosplenomegaly

A. Detection of GATA1 gene mutation

B. Elevated serum bilirubin

C. Bone marrow aspiration showing lymphoblasts

D. Positive Coombs test

A. 2%

B. 5%

C. 10%

D. 25%

A. Ventricular Septal Defect (VSD)

B. Atrioventricular Septal Defect (AVSD)

C. Patent Ductus Arteriosus (PDA)

D. Tetralogy of Fallot (TOF)

A. Increased pulmonary vascular resistance and endothelial dysfunction

B. Decreased systemic vascular resistance

C. Enhanced surfactant production

D. Increased alveolar compliance

A. Right-to-left shunting at atrial level due to low cardiac output

B. Left-to-right shunting through ductus arteriosus

C. Right-to-left shunting via ductus arteriosus due to suprasystemic pulmonary pressures

D. Increased pulmonary venous return

A. Increased nitric oxide synthase activity

B. Decreased endothelin-1 production

C. Interferon receptor overexpression → reduced NO → upregulated endothelin-1

D. Enhanced prostacyclin signaling