Dataset Information

Mucopolysaccharidosis VII in a Cat Caused by 2 Adjacent Missense Mutations in the GUSB Gene.

ABSTRACT:

Background

Mucopolysaccharidoses (MPS) are common lysosomal storage disorders causing typically progressive skeletal and ocular abnormalities.

Objectives

To describe the clinic features, metabolic profile and a unique mutation in a domestic shorthair (DSH) kitten with MPS VII.

Animals

Affected kitten and 80 healthy cats.

Methods

Serum lysosomal enzyme activities and urinary glycosaminoglycan (GAG) accumulation were assessed. Exons of the β-glucuronidase gene (GUSB) were sequenced from genomic DNA and genotyping was conducted.

Results

A 3-month-old DSH cat was presented for stunted growth, paresis, facial dysmorphia, multiple skeletal deformities, and corneal opacities. Evaluation of blood smears disclosed metachromatic granules in leukocytes and a urinary mucopolysaccharide spot test was positive. The proband had no GUSB activity but normal or increased activities for other lysosomal enzymes. Sequencing of the GUSB gene from the proband and comparison to the sequence of 2 healthy cats and the published feline genome sequence demonstrated 2 unique single base transitions (c.1421T>G and c.1424C>T) in exon 9, altering 2 adjacent codons (p.Ser475Ala and p.Arg476Trp). These amino acid changes are in a highly conserved domain of the GUSB protein and nontolerable to maintain function. Moreover, the p.Arg476Trp mutation previously has been identified in human patients. None of the other clinically healthy cats had these mutations.

Conclusions and clinic importance

The diagnostic approach to MPS disorders is delineated. This is only the second mutation known to cause MPS VII in cats. Similarly, 2 different mutations have been described in MPS VII dogs, thereby showing the molecular heterogeneity of MPS VII in companion animals.

SUBMITTER: Wang P

PROVIDER: S-EPMC4624456 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Mucopolysaccharidosis (MPS) VII is a lysosomal storage disorder characterized by deficient activity of β-glucuronidase, leading to progressive accumulation of incompletely degraded heparan, dermatan and chondroitin sulfate glycosaminoglycans (GAGs). Patients with MPS VII exhibit progressive skeletal deformity including kyphoscoliosis and joint dysplasia, which decrease quality of life and increase mortality. Previously, using the naturally-occurring canine model, we demonstrated that one of the earliest skeletal abnormalities to manifest in MPS VII is failed initiation of secondary ossification in vertebrae and long bones at the requisite postnatal developmental stage. The objective of this study was to obtain global insights into the molecular mechanisms underlying this failed initiation of secondary ossification using whole transcriptome sequencing (RNA-Seq). Epiphyseal tissue was isolated from the vertebrae of control and MPS VII affected dogs at 9 and 14 days-of-age (n=5 for each group). Differences in global gene expression across this developmental window for both cohorts were established using RNA-Seq. A targeted analysis focused on signaling pathways important in the regulation of endochondral ossification, and a subset of gene expression changes were validated using qPCR. Principal Component Analysis revealed clustering of samples from each group, indicating clear effects of both age and disease state. At 9 days-of-age, 1375 genes were significantly differentially expression between MPS VII and control, and by 14 days-of-age, this increased to 4719 genes. Osteoactivin (GPNMB) was the top upregulated gene in MPS VII at both ages. Targeted analysis revealed temporal changes in gene expression from 9 to 14 days-of-age in control samples consistent with chondrocyte maturation, cartilage resorption, and osteogenesis. In MPS VII samples, however, elements of key osteogenic pathways such as Wnt/β-catenin and BMP signaling were dysregulated. In conclusion, this study represents the first step towards identifying druggable therapeutic targets and putative biomarkers for bone disease in MPS VII patients during postnatal growth.

Project description:ObjectiveThis study assessed growth patterns in patients with mucopolysaccharidosis (MPS) VII before enzyme replacement therapy.MethodsHeight, weight, and body mass index (BMI) measurements and Z-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, height Z-scores were near normal until 1 year of age but declined thereafter, particularly among males. There was no consistent pattern in weight Z-score. BMI Z-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 weight Z-scores over time versus males without history of NIHF. There was no clear effect of NIHF history on height and weight Z-scores in female patients.ConclusionsIn patients with MPS VII, declines in height Z-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 height Z-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 the Ultragenyx 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.