Mucopolysaccharidosis type IVA (MPS IVA) or Morquio syndrome is a multisystem disorder caused by galactosamine-6-sulfatase deficiency. Skeletal manifestations, including short stature, skeletal dysplasia, cervical instability, and joint destruction, are known to be associated with this condition. Due to the severity of these skeletal manifestations, the non-skeletal manifestations are frequently overlooked despite their significant contribution to disease progression and impact on quality of life. This review provides detailed information regarding the non-skeletal manifestations and suggests long-term assessment guidelines. The visual, auditory, digestive, cardiovascular, and respiratory systems are addressed and overall quality of life as measured by endurance and other functional abilities is discussed. Impairments such as corneal clouding, astigmatism, glaucoma, hearing loss, hernias, hepatomegaly, dental abnormalities, cardiac valve thickening and regurgitation, obstructive sleep apnea, tracheomalacia, restrictive and obstructive respiratory compromise, and muscular weakness are discussed. Increased awareness of these non-skeletal features is needed to improve patient care.
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Competing interests C.J. Hendriksz has received consulting fees, symposium support for himself and team personnel, and research grants from BioMarin. S.M. Hawley is an employee of BioMarin. C. G. Summers has received research funding from the National Organization of Albinism and Hypopigmentation and consulting fees from McKesson Consulting. E. Braunlin has received fees for speaking from BioMarin. K.I. Berger, E. Braunlin, C.J. Hendriksz, C. Mc Ardle, C.G. Summers, and E. Wright received reimbursement for participating in a BioMarin sponsored summit. M. Al-Jawad and R. Lawrence have no competing interests to declare.