Clinical trials on Allan-Herndon-Dudley Syndrome

Allan-Herndon-Dudley Syndrome

Allan-Herndon-Dudley Syndrome, also known as Monocarboxylate Transporter 8 Deficiency, is a rare genetic disorder that affects brain development and function. This condition primarily impacts males and causes problems with movement, muscle tone, and cognitive development due to issues with thyroid hormone transportation in the brain.


  • Cognitive Impairment: Severe learning disabilities due to brain development issues.
  • Muscle Weakness and Hypotonia: Reduced muscle tone can hinder basic physical activities.
  • Motor Skill Delays: Slowed achievement of milestones like crawling or walking.
  • Spasticity: Increased muscle stiffness that can be painful and limit movement.
  • Communication Challenges: Speech development can be significantly delayed or absent.
  • Feeding Difficulties: Problems with swallowing and nutrition can lead to growth issues.
  • Respiratory Problems: Weakness in the respiratory muscles may cause frequent infections and breathing difficulties.

Treatment Methods

  • Thyroid Hormone Therapy: Regulating thyroid hormone levels to support metabolism and brain development.
  • Physical Therapy: Exercises to improve motor functions and muscle strength.
  • Occupational Therapy: Assisting with daily activities and enhancing life skills.
  • Speech Therapy: Focused on improving communication abilities.
  • Supportive Care: Addressing nutrition, respiratory health, and overall wellbeing.


The outlook for individuals with Allan-Herndon-Dudley Syndrome varies widely. While the disorder leads to significant developmental delays and physical limitations, consistent and comprehensive medical and therapeutic intervention can improve quality of life and functionality. Without appropriate treatment, the complications can severely impact longevity and quality of life.
  • CT-EU-00118061

    Withdrawal of tiratricol in males with Monocarboxylate Transporter 8 (MCT8) Deficiency

    This study focuses on Monocarboxylate Transporter 8 (MCT8) Deficiency, a rare genetic disorder that disrupts thyroid hormone transport, leading to severe developmental and neurological issues. The trial investigates the effects of withdrawing tiratricol (a thyroid hormone replacement therapy) in male patients. The goal is to observe changes in thyroid hormone levels and determine if levels rise above normal when tiratricol is stopped, which would require restarting the medication. Participants will receive either tiratricol or a placebo for 30 days or until specific criteria necessitate changes. Regular assessments and monitoring will be conducted to evaluate the effects.

    • Tiratricol
    • placebo