March 16 (Reuters) - BioMarin Pharmaceutical ( BMRN )

will discontinue mid-stage trials of its bone disorder treatment

after reports of several cases of patients' hip joint slipping

out of place, the drugmaker said on Monday, sending its shares

down 4%.

* BioMarin was testing its drug Voxzogo in patients with

Turner Syndrome, SHOX-deficiency and Aggrecan (ACAN)-deficiency,

which are distinct genetic conditions that causes severe short

stature and in some cases abnormal bone development.

* Turner syndrome occurs in females missing part or all of

an X chromosome, SHOX deficiency results from a missing or

faulty growth-related gene, and ACAN deficiency is caused by

mutations in a gene important for cartilage structure.

* During the mid-stage trials, several patients faced

slipped capital femoral epiphysis, where the ball of the hip

joint slips off the thigh bone at the area where the bone is

still growing.

* BioMarin said it will continue testing the drug in

patients with Noonan syndrome where typical development stops in

various parts of the body, and in patients with a form of

unexplained short stature.

* The U.S. Food and Drug Administration approved the

injection Voxzogo in 2021 for patients with achondroplasia, a

form of dwarfism.

* Last month, the FDA approved Ascendis Pharma's ( ASND )

once-weekly injection Yuviwel, making it the second treatment

for achondroplasia to gain U.S. approval.