Table 1.

Common presenting/early symptoms in patients with attenuated MPS I [24, 51]

• Growth delay (normal birth weight, but growth failure or short stature) • Joint contractures (primarily in hands/claw hand deformity), joint pain and stiffness, restricted mobility • Carpal tunnel syndrome (trigger digits) • Recurrent hernias (umbilical and/or inguinal) • Corneal clouding • Hepatosplenomegaly • Skeletal abnormalities/dysostosis multiplex (e.g., kyphosis, scoliosis, hip dysplasia, flattened vertebral bodies, oar-shaped ribs, short thickened clavicles, bullet-shaped phalanges, dysplastic femoral heads, flattened acetabula, coxa valga and genu valgum deformities) • Ear/nose/throat symptoms (recurrent ear infections, noisy breathing, sleep apnea, enlarged tongue, hearing loss) • Heart murmur (valve abnormalities) • Surgical history of multiple hernia repairs, PE tubes, tonsillectomy, adenoidectomy

All symptoms may not be present in the same patient, but are usually progressive. See Fig. 2 for the path to diagnosis