LATE DIAGNOSIS OF MUCOPOLYSACCHARIDOSIS TYPE IVA IN TWO SIBLINGS IN SOUTH COLOMBIA

Introduction: Mucopolysaccharidosis type IV (MPS IV) is an autosomal recessive hereditary disorder of lysosomal storage due to mutations in the N‐acetylgalactosamine‐6‐sulfatase (GALNS) gene. Its incidence is 1 in 75,000 to 1 in 200,000 births, with an equal distribution in men and women (1). Diagnosis is based on clinical manifestations, radiological findings, biochemical tests, and molecular detection. Unfortunately, there is no cure for MPS IVA; although experimental therapies have recently been implemented and new treatments are under development.

Presentation of the case: Two sibling patients with a late diagnosis of Mucopolysaccharidosis type IVA will be presented, the first 41 years old, female with skeletal manifestations such as kyphoscoliosis, C2/C3 osteochondrodysplasia, pectus carinatum, bilateral Perthes disease, flat feet and extra skeletal limitations. range of motion and gait, obstructive sleep apnea, atypical facial features, and short stature. The second, 41 years old, male, with a broad forehead, concave nose, dental abnormalities, kyphoscoliosis, pectus carinatum, shortened extremities, pain when moving the hands, limited gait, and flat feet. In both, a homozygous variant in the GALNS gene of uncertain clinical significance (VUS) was identified in the exome, c.850 T>G p. (Phe284Val).

Discussion: Type IVA mucopolysaccharidosis is a heterogeneous disorder with a diverse spectrum. Our cases contribute to both local and international literature by presenting clinical and skeletal manifestations typical of this pathology as well as molecular diagnostic confirmation.