Severe achondroplasia with developmental delay and acanthosis nigricans

Autosomal dominant - en

Severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN) is a rare genetic disorder characterized by achondroplasia, significant developmental delay, and acanthosis nigricans. This condition is caused by mutations in the FGFR3 gene, which plays a crucial role in bone growth and development.

Clinical Features

Individuals with SADDAN typically present with:

• Severe short stature due to achondroplasia
• Delayed developmental milestones
• Acanthosis nigricans, a skin condition characterized by dark, thick, velvety patches in body folds and creases
• Macrocephaly (abnormally large head)
• Hydrocephalus (accumulation of cerebrospinal fluid within the brain)
• Hypotonia (reduced muscle tone)

Genetics

SADDAN is caused by specific mutations in the FGFR3 gene, which encodes the fibroblast growth factor receptor 3. This gene is crucial for the regulation of bone growth and development. The mutations lead to an overactive FGFR3 protein, which disrupts normal bone growth and leads to the characteristic features of the disorder.

Diagnosis

Diagnosis of SADDAN is based on clinical evaluation, family history, and genetic testing to identify mutations in the FGFR3 gene. Prenatal diagnosis is possible if the mutation is known in the family.

Management

There is no cure for SADDAN, and treatment is primarily supportive and symptomatic. Management strategies may include:

• Physical therapy to improve motor skills and muscle strength
• Special education services to address developmental delays
• Regular monitoring and treatment of complications such as hydrocephalus and spinal stenosis
• Dermatological treatments for acanthosis nigricans

Prognosis

The prognosis for individuals with SADDAN varies depending on the severity of the symptoms and the presence of complications. Early intervention and supportive care can improve the quality of life for affected individuals.

Related Pages

• Achondroplasia
• Acanthosis nigricans
• FGFR3
• Developmental delay
• Genetic disorders

See Also

• Hypochondroplasia
• Thanatophoric dysplasia
• Skeletal dysplasia