Summary about Disease
Thanatophoric dysplasia (TD) is a severe skeletal disorder characterized by extremely short limbs and a narrow thorax (chest). It is a type of skeletal dysplasia, specifically a chondrodysplasia, meaning it affects cartilage and bone development. There are two main types, type I and type II, distinguished by specific features, most notably the shape of the femurs (thigh bones) and skull. TD is a lethal condition, with most infants dying shortly after birth due to respiratory failure.
Symptoms
Extremely short limbs (micromelia)
Narrow thorax (chest), leading to respiratory problems
Relatively large head with a prominent forehead
Short ribs
Curved, shortened femurs (thigh bones) – often resembling a telephone receiver in Type I
Cloverleaf skull (Kleeblattschädel) may be present, especially in Type II
Flattened vertebrae (platyspondyly)
Causes
Thanatophoric dysplasia is caused by mutations in the FGFR3 gene. This gene provides instructions for making a protein called fibroblast growth factor receptor 3, which plays a role in bone and brain tissue maintenance and growth. The mutations in the *FGFR3* gene lead to an overactive receptor, which interferes with normal bone growth, particularly in the limbs and ribs. The condition is autosomal dominant, meaning that only one copy of the mutated gene is needed to cause the disorder. Most cases result from new mutations, meaning they occur spontaneously and are not inherited from parents.
Medicine Used
There is no cure for Thanatophoric dysplasia. Medical management focuses on providing supportive care. Potential interventions include:
Respiratory Support: Mechanical ventilation to assist with breathing.
Tracheostomy: A surgical procedure to create an opening in the trachea (windpipe) to assist with breathing.
Chest Tube Placement: May be required to drain air or fluid from around the lungs (pneumothorax or pleural effusion)
Pain Management: Providing comfort and pain relief.
Is Communicable
No, Thanatophoric dysplasia is not communicable. It is a genetic disorder caused by a mutation in a gene and cannot be spread from person to person.
Precautions
Since TD is a genetic condition, there are no precautions to prevent its occurrence in the general population. For families with a history of TD or related skeletal dysplasias, genetic counseling and prenatal testing (such as amniocentesis or chorionic villus sampling) may be offered to assess the risk of recurrence.
How long does an outbreak last?
Thanatophoric dysplasia is not an infectious disease and does not occur in outbreaks. It is a genetic disorder present from conception.
How is it diagnosed?
Prenatal Ultrasound: Shortened limbs, a narrow chest, and other skeletal abnormalities may be detected during routine prenatal ultrasound examinations.
Radiography (X-rays): X-rays after birth can confirm the diagnosis by revealing the characteristic skeletal abnormalities, such as short ribs, curved femurs, and flattened vertebrae.
Genetic Testing: Molecular genetic testing to identify mutations in the FGFR3 gene can confirm the diagnosis.
Timeline of Symptoms
Symptoms are present in utero and can be detected by prenatal ultrasound. After birth, the most immediate and critical symptoms relate to respiratory distress. There is no progressive timeline of symptoms, as the condition is typically lethal within a short period after birth.
Important Considerations
Prognosis: The prognosis for infants with TD is extremely poor. Most infants die shortly after birth due to respiratory failure.
Ethical Considerations: Decisions regarding medical interventions and palliative care should be made in consultation with medical professionals, ethicists, and the family, considering the infant's quality of life and comfort.
Family Support: Families affected by TD require significant emotional and psychological support.
Recurrence Risk: Genetic counseling is essential to discuss the recurrence risk in future pregnancies and options for prenatal diagnosis.
Variability: The severity of TD can vary somewhat, and in very rare cases, infants may survive longer with intensive medical support, although they typically have significant developmental challenges.