Mucopolysaccharidoses and oligosaccharidoses — branching viva

Viva brief

A three-year-old who appeared normal at birth is referred for progressive coarsening of the facial features, snoring, and slowing of speech. Examination reveals macroglossia, hepatosplenomegaly, claw-hand deformity, and a thoracolumbar gibbus, with dysostosis multiplex on the skeletal survey. ^{[1] [2]}

Stem question: What is your unifying diagnosis family, what is your stepwise investigation, and how does central-nervous-system involvement govern the treatment? ^{[1] [2]}

Branch 1 (clear cornea, a boy): The cornea is clear. How does this redirect the subtype, what is the inheritance, and which family members should be screened? ^{[1] [2]}

Branch 2 (preserved intellect, striking skeletal dysplasia): The intellect is entirely preserved, but the trunk is short, the neck short, and the cervical spine unstable. Name the subtype, its cardinal complication, and the surveillance it demands. ^[3]

Branch 3 (infant with coarse facies, gingival hyperplasia, elevated plasma lysosomal enzymes): An infant presents with coarse features, striking gingival hyperplasia, restricted joints, and cardiomegaly, but plasma lysosomal enzymes are markedly elevated. Name the disorder and explain the paradox. Contrast its prognosis with severe Hurler and explain why Hurler is transplantable while this disorder is not. ^{[2] [4]}