Turner syndrome (TS) is characterized by a missing whole or part of the second sex chromosome
in a phenotypic female, resulting in short stature due to haploinsufficiency of the SHOX
gene. Growth hormone (GH) is an approved therapy for this condition, although not associated
with GH deficiency, and benefits are modest. Vosoritide, a C-type natriuretic peptide (CNP)
analog, targets chondrocytes within the growth plate leading to increased cell proliferation
and hypertrophy. We hypothesize that patients with TS and short stature will respond to
vosoritide treatment leading to increased growth velocity. This study will enroll
pre-pubertal girls with TS who are either naïve to GH or have had a poor response to GH
therapy. All subjects will be treated with vosoritide for 12 months and will be assessed for
safety monitoring and improvement in height outcomes. Annualized growth velocity (AGV) on
vosoritide will be compared to AGV in the 6-18 months prior to initiation of vosoritide based
on historical data available in the medical record. Subjects with a positive response to
therapy will be given the option to continue in the extension phase of the study during which
they will continue to receive vosoritide until growth cessation.