Carnosinemia is a sporadic genetic disorder that specifically affects the metabolism of dietary protein.¹ Impacting men and women equally, the disease has only been diagnosed in 30 people worldwide and remains relatively unheard of, with key characteristics including developmental delays and seizures.¹ 

Unfortunately, there is currently no approved treatment for this condition.² However, interventions including physical, occupational and speech therapy can help to alleviate symptoms. This article aims to empower both patients and their families by examining the role of therapy in care. 

Understanding carnosinemia 

In cases of carnosinemia, mutations passed on through both the mother and the father (autosomal recessive) result in a deficiency of the carnosinase enzyme.² When the body functions normally, this enzyme is responsible for breaking down proteins (carnosine and anserine) found within meat.¹ However, in patients with carnosinemia, this does not occur and means levels of carnosine build up within body fluids and tissues.² It is thought that this biochemical imbalance affects the brain and the way nerves control muscles. 

Symptoms usually begin in childhood. However, some patients remain without them (asymptomatic). Notably, early signs to look out for include:

• Drowsiness and or seizures that are followed by involuntary, sudden jerking movements¹
•  Low muscle tone (hypotonia)¹
•  Developmental delays, such as impaired speech or learning difficulties¹ 

Treatment focuses on managing symptoms due to a lack of understanding of the underlying cause.

Physical therapy 

Hypotonia, also known as low muscle tone, is a primary characteristic of this disease. Infants with this condition typically appear floppy and struggle to maintain their head position up.³ Additionally, this means children with carnosinemia may take longer to achieve milestones like rolling, sitting, and walking.⁴ Physical therapy is an excellent way to both manage and work towards these goals.

Therapeutic goals:

•  Enhance muscle strength and coordination⁵
• Promote key development milestones (rolling, sitting, crawling, standing, and walking)⁶
• Prevent contractures (shortening of muscles due to limited range of motion), deformity, and misalignment of the spine⁶

These issues are addressed through a combination of training interventions, including:

• Strength training for proper posture⁴
• Treadmill training to promote gait development⁷
• Stretching, joint mobilisation, and positioning techniques to maintain range of motion⁷ 

For families, it is essential to note that progress takes time. Improvements in posture and key milestones may take weeks to months and require consistency and patience. Sessions are needed at school, in the clinic, and at home to maintain an effective treatment regimen. Having small achievable goals gives you the proper steps forward. Consider small accomplishments, such as being able to sit upright unassisted or crawl over a short distance. With small and achievable milestones, the bigger ones are quick to follow.

Occupational therapy

This is crucial in ensuring patients can perform their daily tasks. Over time, this will lead to increased independence and improved quality of life.⁸

Therapeutic goals: 

• Enhancing coordination and control:
  • Grasping, manipulating objects, handwriting, and using utensils⁸
• Supporting self-care:
  • Dressing, eating, and performing daily tasks using adaptive equipment⁸
• Encourage engagement:
  •  Through therapeutic play, crafts, and schoolwork⁸

Interventions & tools:

• Activities to promote grasping, coordination (bilateral and hand-eye), and manipulation of small objects (beads or Lego)⁹
• Adaptive equipment:
  • Pencil grips, modified cutlery and button or zipper aids⁹
• Sensory strategies:
  •  Tactile play, weighted vests, and sensory balls⁹

Early occupational therapy in hypotonic infants can help reduce movement difficulties and support the brain in processing touch, sound, and other sensory inputs.⁴ Additionally, parent-delivered interventions are shown to improve developmental outcomes.⁴ Effectiveness further increases when caregivers use these techniques daily. With occupational therapy, families can integrate exercises into their daily routines at home, school, and during play.

Speech and language therapy (SLT)

Hypotonia of the facial muscles in carnosinemia can affect both speaking and feeding.¹⁰ For patients, speech and language therapy addresses communication and swallowing issues that may arise, which are critical for independence and safety.

Therapeutic goals: 

• Develop expressive/receptive language
• Improve oral-motor function for speech clarity and feeding
• Implement Augmentative and Alternative Communication (AAC) when speech is delayed
•  Ensure safe and age-progression-appropriate feeding

Techniques:

• Play-based language stimulation, including naming, requesting, and singing in daily routine¹⁰
• Oral-motor exercises:
  • Lip and tongue resistance, puffing cheeks, improving articulation¹⁰
• Systems like picture exchange, sign language, or speech-generating devices to support early communication¹⁰
• Feeding/swallowing therapy:
  • Texture progression, safe posture, swallowing exercises, and strategies to prevent choking.

Although not specific to carnosinemia, studies on hypotonia have shown that early SLT improves feeding safety and language performance.¹¹ In chronic conditions, therapy in naturalistic, family-centred settings boosts communication outcomes.¹² Parents learn and apply daily communication and feeding methods. SLTs collaborate with educators to provide classroom speech support.

Starting therapy: what to expect

Beginning therapy can feel overwhelming at first, but knowing what to expect helps ease the transition. Your child will start with an initial evaluation from each therapist. In doing so, these assessments help provide a comprehensive understanding of the whole picture and how to support your child most effectively. 

The team will work to set realistic and achievable milestones to improve quality of life. This can be broken down further into short-term goals, such as sitting up independently or crawling for a short distance, and longer-term objectives, like improving walking or speech. Therapy sessions will be scheduled as needed, based on the patient’s individual needs. However, it is essential to note that these sessions may take place at home, in school, at a clinic, or virtually, offering flexibility that suits the patient and their family. Crucially, therapy continues at home. Patients and caregivers play a central role in creating consistent progress. Therapists will further help guide you through this process. As your child’s progress is monitored, the plan will be adjusted and evaluated to meet their ever-changing needs. 

Emotional and practical support

Caring for a child, especially with a rare disease, can also take its toll, both emotionally and practically. Many families find support through early intervention programs. Specifically for children under three with developmental needs. Importantly, working with your local medical centre will help you to understand the services available in your area. Support also extends to school and classroom accommodations, as well as school therapists, who can all provide tailored learning and support.

Inspiring hope

Although carnosinemia is a lifelong condition, therapy can significantly improve the quality of life for patients. Whilst progress may look different to each child, each step is a way forward to give them independence and lay the foundation for what they want to achieve. With the proper support and tailored plan, every step can be one worth celebrating and bringing families closer together.  

Summary

Carnosinemia is a sporadic genetic disorder that affects how the body breaks down specific proteins, leading to developmental delays, low muscle tone, and seizures. While there is no cure, therapy plays a key role in improving daily function and overall quality of life.

Physical, occupational, and speech-language therapies each target different needs. Physical therapy helps children gain strength and coordination to reach movement milestones. Occupational therapy focuses on developing everyday skills such as feeding, dressing, and playing. Speech therapy supports communication and safe eating, especially when facial muscle tone is weak.

These interventions must be personalised and adjusted as the child grows. Sessions may take place at home, school, or in a clinic, but real progress depends on consistency and caregiver involvement. Parents play a crucial role in helping children apply therapeutic skills to their daily lives.

Though carnosinemia is rare, it does not limit potential. With patience, dedication, and the proper support, children can develop greater independence and confidence. Every small step forward is a meaningful achievement and a reason to stay hopeful.