Craniometaphyseal dysplasia dominant type

Craniometaphyseal Dysplasia, Dominant Type (CMD-D) is a rare genetic disorder characterized by abnormal bone growth and development, particularly affecting the skull (cranium) and the long bones in the arms and legs (metaphyses). This condition is one of the types of Craniometaphyseal Dysplasia (CMD), with the dominant type indicating its pattern of inheritance.

Symptoms and Characteristics

Individuals with CMD-D typically exhibit a range of symptoms, which can vary significantly in severity. Common features include:

• Facial Abnormalities: Prominent forehead, wide nasal bridge, and an increased distance between the eyes (hypertelorism).
• Dental Issues: Delayed tooth eruption, misaligned teeth due to jaw abnormalities.
• Bone Thickening: Abnormal thickening of the cranial bones, leading to increased intracranial pressure, and possibly affecting vision and hearing.
• Narrowing of Nasal Passages: Leading to breathing difficulties and chronic sinusitis.
• Skeletal Abnormalities: Including bowing of the long bones, and sometimes leading to pain or mobility issues.

Causes and Genetics

CMD-D is caused by mutations in the ANKH gene, which plays a crucial role in the regulation of mineral deposition in bones. The condition is inherited in an autosomal dominant pattern, meaning a single copy of the altered gene in each cell is sufficient to cause the disorder. Individuals with a parent who has CMD-D have a 50% chance of inheriting the condition.

Diagnosis

Diagnosis of CMD-D is primarily based on clinical examination and the characteristic features observed in radiographic studies. Genetic testing can confirm the diagnosis by identifying mutations in the ANKH gene.

Treatment

There is no cure for CMD-D, and treatment focuses on managing symptoms and improving quality of life. Interventions may include:

• Surgical Procedures: To relieve increased intracranial pressure, correct skeletal deformities, or address severe dental malocclusions.
• Hearing and Vision Support: Use of hearing aids or corrective lenses as needed.
• Physical Therapy: To maintain mobility and manage pain.

Prognosis

The prognosis for individuals with CMD-D varies depending on the severity of symptoms. With appropriate management, most can lead a normal life, although they may require ongoing treatment for complications such as hearing loss or vision problems.

See Also

• Craniometaphyseal Dysplasia
• Genetic Disorders
• Bone Dysplasia