Mucopolysaccharidoses in Cats: 2025 Vet Insights 🐱🔬

Hello! I’m Dr Duncan Houston BVSc, feline veterinarian and founder of Ask A Vet. In 2025, we explore mucopolysaccharidoses (MPS)—inherited lysosomal storage diseases in cats caused by enzyme deficiencies that prevent breakdown of glycosaminoglycans (GAGs). Accumulation of GAGs damages tissues, triggering progressive skeletal, ocular, cardiac, and neurologic disease. We focus on MPS I, VI & VII, common in Siamese and other breeds, and discuss diagnosis, supportive care, and cutting-edge therapies like enzyme replacement and gene therapy. Plus, learn how telehealth tools—Ask A Vet, Woopf & Purrz—support at-home monitoring. 💙

📌 What Are Mucopolysaccharidoses?

MPS are inherited metabolic disorders where lysosomal enzymes needed to degrade GAGs are missing or inactive, leading to their toxic buildup in cells and tissues :contentReference[oaicite:3]{index=3}. In cats, the notable subtypes are:

• MPS I – α-L‑iduronidase deficiency (similar to Hurler syndrome in humans) :contentReference[oaicite:4]{index=4}.
• MPS VI – arylsulfatase B deficiency (Maroteaux–Lamy syndrome) often seen in Siamese ancestry :contentReference[oaicite:5]{index=5}.
• MPS VII – β-glucuronidase deficiency (Sly syndrome), very rare :contentReference[oaicite:6]{index=6}.

⚠️ Why It Matters

• Progressive, multi-system disease—skeletal dysplasia, facial dysmorphia, corneal opacity, heart murmurs, neurologic deficits :contentReference[oaicite:7]{index=7}.
• Severe cases appear early—growth stagnation, deformities by 6–8 weeks; spinal cord compression by months :contentReference[oaicite:8]{index=8}.
• Historically fatal, but emerging treatments offer hope for quality of life and lifespan extension :contentReference[oaicite:9]{index=9}.

👥 Which Cats Are Affected?

• Autosomal recessive inheritance—two carrier parents needed :contentReference[oaicite:10]{index=10}.
• MPS VI is most noted in Siamese and related breeds; domestic shorthairs also affected by MPS I, VI or VII :contentReference[oaicite:11]{index=11}.
• Genetic testing (particularly for the L476P ARSB mutation in MPS VI) is recommended for breeding cats :contentReference[oaicite:12]{index=12}.

🔍 Signs & Symptoms

Common to all MPS

• Growth retardation—small stature, dwarfism, broad/flat face, large paws :contentReference[oaicite:13]{index=13}.
• Skeletal and joint abnormalities—vertebral fusion, limb stiffness, hip luxation :contentReference[oaicite:14]{index=14}.
• Ocular changes—corneal clouding, optic issues :contentReference[oaicite:15]{index=15}.
• Cardiac valvular thickening and murmurs :contentReference[oaicite:16]{index=16}.
• Neurologic deficits—especially in MPS VI: hind-limb weakness, proprioceptive loss :contentReference[oaicite:17]{index=17}.
• Organ enlargement—liver, spleen—+ potential respiratory compromise :contentReference[oaicite:18]{index=18}.

🔬 Diagnostic Approach

1. History & exam: Note early-onset physical and neurologic signs; breed information :contentReference[oaicite:19]{index=19}.
2. Laboratory tests: CBC, biochemistry, urinalysis often reveal vacuolated leukocytes :contentReference[oaicite:20]{index=20}.
3. Radiographs: Evaluate skeletal dysplasia, joint and spinal changes :contentReference[oaicite:21]{index=21}.
4. Enzyme assays: Confirm α‑L‑iduronidase (MPS I) or ASB (MPS VI) deficiencies :contentReference[oaicite:22]{index=22}.
5. Genetic testing: Identify mutations such as L476P ARSB in Siamese lines :contentReference[oaicite:23]{index=23}.
6. Ocular & cardiac exams: Check for corneal clouding and valve anomalies :contentReference[oaicite:24]{index=24}.

🛠️ Management & Care

A. Supportive & Symptomatic Care

• Pain relief—NSAIDs or opioids—for musculoskeletal discomfort.
• Physiotherapy and gentle exercise to relieve stiffness and maintain mobility.
• Regular ocular lubrication to ease corneal clouding symptoms :contentReference[oaicite:25]{index=25}.
• Cardiac monitoring and supportive care for valvular lesions.
• Soft bedding and stair access to protect fragile joints.

B. Advanced Therapies (2025)**

• Enzyme Replacement Therapy (ERT): α‑L‑iduronidase administration in MPS I shows biochemical and histologic improvement :contentReference[oaicite:26]{index=26}.
• Stem Cell Transplant & Gene Therapy: HSCT and AAV-based gene transfer show promising results in feline MPSVI models :contentReference[oaicite:27]{index=27}.
• Emerging treatments may correct storage in the brain and heart—ongoing research :contentReference[oaicite:28]{index=28}.

🌱 Prognosis & Monitoring

• Prognosis varies—mild cases may live into adolescence; severe early-onset cases may succumb by months :contentReference[oaicite:29]{index=29}.
• Ongoing supportive care and advanced therapies can significantly enhance quality of life.
• Lifelong monitoring—growth, vision, mobility, and heart health—key to timely intervention.

🏠 Telehealth & Home-Care Tools

• Ask A Vet: Guides symptom tracking, pain management, exercise plans, and when to seek in-clinic care.
• Woopf: Delivers joint supplements, pain meds, physiotherapy tools, and ocular care supplies.
• Purrz: Tracks mobility, appetite, behavior changes, ocular/respiratory signs with smart alerts for veterinarians.

🛡️ Prevention & Breeding Strategies

• Genetic testing is essential to prevent breeding of carriers—especially in Siamese and related breeds :contentReference[oaicite:30]{index=30}.
• Do not breed known carriers or affected cats.
• Educate breeders about MPS inheritance to reduce prevalence clinically.

🔬 2025 Innovations & Research

• AAV gene therapies that restore enzyme production system‑wide are being trialed :contentReference[oaicite:31]{index=31}.
• Improved ERT dosing and immune modulation to reduce antibody responses :contentReference[oaicite:32]{index=32}.
• Expansion of breed-specific DNA panels for early detection and elimination from breeding populations.
• Smart home and telehealth integration via Purrz to alert owners and vets to early changes.

✅ Vet‑Approved Care Roadmap

1. Identify early signs—stunted growth, dysmorphic features, joint issues.
2. Pursue enzyme assays and genetic testing for MPS subtype identification.
3. Implement supportive care—pain relief, joint management, ocular support.
4. Evaluate eligibility for advanced therapies—ERT or gene therapy.
5. Utilize telehealth tools for home monitoring and intervention guidance.
6. Reassess physical, ocular, and cardiac status every 3–6 months.
7. Work with breeders on genetic screening protocols to prevent future cases.
8. Adjust long‑term care to maintain comfort and mobility.

✨ Final Thoughts from Dr Houston

Mucopolysaccharidoses in cats are rare but potentially devastating. However, with early detection, supportive management, and 2025’s cutting-edge treatments—ERT, gene therapy—and home-care via tools like Ask A Vet, Woopf, and Purrz, affected cats can live fuller, more comfortable lives. Genetic testing ensures we reduce future incidence and protect feline health long-term. Your vigilance and care truly make a positive difference. 💙🐾

Need expert guidance? Visit AskAVet.com or download our app for personalized support—from symptom monitoring to therapy access and at-home care tips for cats with mucopolysaccharidosis.