Lysosomal Storage Disorders

A 3-year-old boy from Tamil Nadu presents with progressive hepatosplenomegaly, developmental delay, and recurrent respiratory infections over the past 18 months. On examination, he has coarse facial features, corneal clouding, and a palpable spleen 8 cm below the costal margin. Bone marrow aspirate shows foamy macrophages. Serum acid phosphatase is markedly elevated. What is the most likely diagnosis?

A 6-month-old girl from Kerala presents with progressive irritability, seizures, developmental regression, and loss of previously acquired milestones over 3 months. On examination, she has a cherry-red spot on the macula, hepatosplenomegaly, and hypotonia. Serum sphingomyelinase activity is severely reduced. Bone marrow shows sea-blue histiocytes. What is the most likely diagnosis?

A 3-year-old boy from Tamil Nadu presents with progressive hepatosplenomegaly, developmental delay, and cherry-red spot on the macula. His parents are consanguineous. Which investigation is most appropriate to confirm the diagnosis of GM1 gangliosidosis?

A 2-year-old girl presents with coarse facial features, corneal clouding, hepatosplenomegaly, and stiff joints. Her urine shows elevated heparan sulfate and dermatan sulfate. Which is the most specific investigation to confirm the diagnosis of mucopolysaccharidosis type I (Hurler syndrome)?

Which enzyme is deficient in Gaucher disease, the most common lysosomal storage disorder?