An 18-month-old girl is brought to the physician by her parents because of developmental delays since the age of 9 months. She has a history of recurrent otitis media. She underwent bilateral inguinal hernia repair at the age of 12 months. Her vocabulary consists of 2 single words, and she is starting to walk with assistance. She is at the 10th percentile for length and the 25th percentile for weight. Physical examination shows generalized hirsutism, a prominent forehead with full cheeks, cloudy corneas, a depressed nasal bridge, and rhinorrhea. There is moderate hepatomegaly. The catabolism of which of the following is most likely abnormal in this patient?

Question

Quizplus · Accepted Answer

The symptoms and physical findings are suggestive of Hurler syndrome, a type of mucopolysaccharidosis, where there is an abnormal catabolism of glycosaminoglycans. The symptoms present in this child are most closely associated with a deficiency in the β-galactosidase-1 gene (GLB1) which is a lysosomal enzyme involved in the degradation of keratin sulfates, G_M1 gangliosides (G_A1), and glycoprotein-derived oligosaccharides.

An 18-Month-Old Girl Is Brought to the Physician by Her