LAUSR

A 21-month-old boy (Figure 1a; Figure 1b) presented to the surgery department with foot and spine deformity. He was born after a fullterm pregnancy with no complications. His parents were healthy and nonconsanguineous. Birth anthropometric parameters were within the normal standard range. His birth weight was 3310 g (46th percentile), birth height was 50 cm (52nd percentile), and head circumference was 34 cm (36th percentile). Apgar scores at 1 and 5 min were 10 and 10, respectively. His foot deformity was treated with plaster splints but worsened during the next few months. Throughout his infancy, he suffered from recurrent bronchoconstriction and pneumonia. Further disease progression led to deleterious skeletal and joint manifestations with disproportionate short stature, short neck, pectus carinatum deformity of the chest, short trunk, spinal scoliosis, genus valgus deformity of the knee, and abnormal gait. At 5 years (Figure 1c), he had a body height of 86 cm (less than the 3rd percentile). Due to the worsening of his skeletal manifestations, a rare lysosomal storage disease was suspected. A diagnosis of Morquio A syndrome was established, with enzyme galactosamine-6-sulfate sulfatase activity <0.1 μmol/l/h (reference range ≥ 2.0 μmol/l/h) caused by two heterozygous mutations in the protein-coding GALNS (Galactosamine (N-Acetyl)-6-Sulfatase) gene. The first mutation was located in exon 5, NM_001323544.1:c.364G>A (p.Gly122Ser), and the second in exon 9, NM_001323544.1:c.878C>T (p.Ser293Leu). The GALNS gene was analyzed by PCR and sequencing of the entire coding region and the highly conserved exon-intron splice junctions. The reference sequences of the GALNS gene were NM_001323544.1 and NM_000512.4.