Mucopolysaccharidosis Type IVA (GALNS)
Mucopolysaccharidosis type IVA (MPS IVA), also known as Morquio syndrome A, is an autosomal recessive disorder caused by pathogenic variants in the gene GALNS. MPS IVA has a variable age of onset and rate of progression. It is generally diagnosed during the second year of life and is associated with joint laxity, ulnar deviation of the wrist, and inguinal hernia, but can also present with kyphoscoliosis, knock-knee, and pectus carinatum, which can lead to short stature, pain, and arthritis. Effects on other organ systems may include respiratory compromise, obstructive sleep apnea, valvular heart disease, hearing impairment, visual impairment, dental abnormalities, and hepatomegaly. Life expectancy for these patients varies depending on the severity of the disorder and the quality of care. Generally, patients with the severe form of the disorder do not survive beyond the third decade of life, while patients with an attenuated form may survive past 70 years of age.
For information about carrier frequency and residual risk, please see the residual risk table.