BioMarin Pharmaceutical Inc.'s medicine Vimizim became the first therapy to be approved in China for treating patients with a type of ultra-rare metabolic disorder called Morquio A syndrome.

Mucopolysaccharidosis type IVA, also called Morquio syndrome type A, is a rare metabolic disorder that primarily affects the skeleton. The condition, which becomes apparent during early childhood, is caused when the body does not produce an enzyme needed in the breakdown and removal of glycosaminoglycans called keratan sulfate and chondroitin-6-sulfate. As a result, glycosaminoglycans collect in cells, blood and connective tissue and cause damage over time.

The rate of incidence of the disorder is estimated to vary between one in 200,000 live births and one in 450,000 live births, the company said in its June 4 press release. BioMarin said an estimated 3,000 patients in the developed world are affected by Morquio A syndrome.

In May 2018, the Chinese government issued its first national list of rare diseases, which included Morquio syndrome and in August 2018, the country posted a list of 48 drugs already approved in the U.S., EU or Japan that could be eligible for priority review, which included Vimizim.