Modelling Morquio A syndrome: an anthropometric study of body characteristics and stature

Abstract Background: Morquio A syndrome, or mucopolysaccharidosis (MPS) IVA is an autosomal recessive, life-limiting lysosomal storage disease caused by deficient activity of the enzyme galactosamine-6-sulfatase. Common early symptoms such as abnormalities of body stature can facilitate timely diagnosis. The aim of this study was to create a pattern of face and body stature based on anthropometric measurements taken from a cohort of Polish patients with MPS IVA. Methods: Analysis of 11 somatometric and 14 craniofacial features was performed on 20 patients with MPS IVA, aged from 3 months to 26 years. Diagnosis of MPS IVA was confirmed by enzymatic and molecular analysis. Two-tailed t-tests were used to compare mean values for body length and weight at birth between the MPS IVA patients and the general population. To show the degree and direction of deviation z-scores were calculated and then used to construct a model of an average MPS IVA patient. Results: Mean values for body height and weight at birth were greater for boys than for the general population. The observed pattern of head and body shape indicated that dwarfism occurred with increasing age as a result of relatively short trunk and lower limbs. Skeletal abnormalities included a bell-shaped chest with ratio of chest depth and chest width was significantly above the norm. The head and neck were relatively elongated in comparison to body height and tucked between narrow shoulders. The head was narrow and elongated, while the nose was short with wide nostrils. Conclusions: Multiple measurements – including age ranges – allowed the creation of a model that showed the most characteristic features of the MPS IVA phenotype.