Background: Mucopolysaccharidosis type I (MPS I) is a rare, progressive multisystem genetic disorder. A homozygous pathogenic variant causing frameshift (IDUA c.19_20insCGGCCCCC) has been reported in Boston Terriers with MPS I. However, clinical data, particularly regarding disease progression and long-term outcome, are poorly understood.
Objectives: To characterize clinical features, disease progression, and long-term outcome of MPS I in Boston Terriers with the previously reported pathogenic variant. Animals: Five client-owned Boston Terriers with MPS I confirmed by genetic testing.
Methods: A case series of dogs with MPS I for which medical records, follow-up contact with owners, and completed questionnaires were available.
Results: The median age at genetic diagnosis was 21 months (range: 12–53 months old). Four dogs were still alive at the time of the abstract submission, and their median age was 59 months old (range: 34–84 months old), while the other dog was euthanized at 54 months old due to disease progression. The most common initial clinical signs owners noticed were corneal clouding (3/5) or neck pain (2/5). All dogs eventually developed corneal clouding; other findings included joint stiffness, neck/back pain, gait abnormalities, abnormal spine morphology, and heart murmurs. Conclusions and clinical importance: Although the number of cases included in this study is limited, Boston Terriers with MPS I demonstrated progressive multisystem involvement with a prolonged survival into mid-adulthood. Considering the survival period observed to date following genetic diagnosis, disease progression does not appear to be rapidly progressive; this information may aid owner counseling.
.jpg "Yoshihiko Yu, BVetMed, PhD (he/him/his) photo")