Mucopolysaccharidosistype IX (HYAL1)
Mucopolysaccharidosis type IX is a very rare autosomal recessive disorder caused by pathogenic variants in the gene HYAL1. Clinical features include short stature and joint abnormalities, including cysts and swelling. Frequent ear infections have also been reported. Life expectancy is not known, but is not likely to be significantly reduced. No genotype-phenotype correlation has been reported.
For information about carrier frequency and residual risk, please see the residual risk table.