ObjectiveThis study assessed growth patterns in patients with mucopolysaccharidosis (MPS) VII before enzyme replacement therapy.MethodsHeight, weight, and body mass index (BMI) measurements andZ-scores from patients from three clinical studies were compared with those from CDC healthy population growth charts. Relationships with age/sex and history of non-immune hydrops fetalis (NIHF) were assessed by linear regression and ANOVA, respectively.ResultsAmong 20 enrolled patients with MPS VII, heightZ-scores were near normal until 1 year of age but declined thereafter, particularly among males. There was no consistent pattern in weightZ-score. BMIZ-scores were above normal and increased slightly with age among males and were slightly below normal among females. Male patients with a history of NIHF had greater declines in height and weightZ-scores over time versus males without history of NIHF. There was no clear effect of NIHF history on height and weightZ-scores in female patients.ConclusionsIn patients with MPS VII, declines in heightZ-score began early in life, particularly among males, while changes in BMI varied by sex. Patients with MPS VII and a history of NIHF had greater declines in heightZ-score with age than did patients without a history of NIHF.Clinical trial registration:This retrospective analysis included patients enrolled in an open-label phase 2 study (UX003-CL203;ClinicalTrials.gov,NCT02418455), a randomized, placebo-controlled, blind-start phase 3 study (UX003-CL301;ClinicalTrials.gov,NCT02230566), or its open-label, long-term extension (UX003-CL202;ClinicalTrials.gov,NCT02432144). Requests for individual de-identified participant data and the clinical study report from this study are available to researchers providing a methodologically sound proposal that is in accordance with theUltragenyx data sharing commitment. To gain access, data requestors will need to sign a data access and use agreement. Data will be shared via secured portal. The study protocol and statistical analysis plan for this study are available on the relevant clinical trial registry websites with the tabulated results.