Triphalangeal thumb polysyndactyly syndrome

Triphalangeal Thumb Polysyndactyly Syndrome (TPTPS) is a rare genetic disorder characterized by the presence of an extra phalanx in the thumb, resulting in a three-phalangeal thumb, combined with polysyndactyly, which is the condition of having more fingers or toes than normal. This syndrome falls under the broader category of limb malformations, which can affect the development of the hands and feet.

Etiology

The etiology of Triphalangeal Thumb Polysyndactyly Syndrome is genetic. It is often associated with mutations in specific genes that are crucial for limb development during embryogenesis. These mutations can be inherited in an autosomal dominant manner, meaning only one copy of the altered gene in each cell is sufficient to cause the disorder. However, cases have been reported where the syndrome appears without any known family history, suggesting de novo mutations or previously undetected genetic variations in families.

Clinical Features

Individuals with TPTPS exhibit a range of phenotypic manifestations, primarily including:

• The presence of a three-phalangeal thumb, which is longer than a normal thumb and may have limited function or be fully functional.
• Polysyndactyly, which involves the duplication of fingers or toes. This can vary in severity from partial to complete duplication, and can affect one or more limbs.
• Other possible limb anomalies, such as syndactyly (fusion of fingers or toes), brachydactyly (shortening of fingers or toes), or oligodactyly (fewer fingers or toes than normal).

Diagnosis

Diagnosis of Triphalangeal Thumb Polysyndactyly Syndrome is primarily based on physical examination and the clinical features observed. Radiographic imaging can confirm the presence of extra phalanges and detail the extent of polysyndactyly and other bone abnormalities. Genetic testing may be utilized to identify mutations associated with the syndrome, aiding in confirmation of the diagnosis and understanding of the genetic basis.

Management and Treatment

Management of TPTPS is multidisciplinary, involving orthopedic surgeons, geneticists, and physical therapists, among others. Treatment is primarily surgical and aims to improve the function and appearance of the hands and feet. This may include separation of fused digits, removal of extra digits, and reconstruction of the thumb to enhance its functionality. Physical therapy is often recommended to improve mobility and strength post-surgery.

Prognosis

The prognosis for individuals with Triphalangeal Thumb Polysyndactyly Syndrome largely depends on the severity of the limb malformations and the success of surgical interventions. With appropriate management, most individuals can achieve good functional outcomes and lead normal, active lives.

See Also

• Syndactyly
• Polydactyly
• Brachydactyly
• Limb malformation