From the Guidelines
Syndactyly is primarily caused by genetic factors, with both inherited and spontaneous genetic mutations playing significant roles, as supported by recent studies 1. The condition occurs when the normal separation of fingers or toes fails during fetal development, typically between the 6th and 8th weeks of pregnancy. Risk factors include a family history of syndactyly, as it can be inherited in an autosomal dominant pattern, meaning a child has a 50% chance of inheriting the condition if one parent has it. Syndactyly can also occur as part of genetic syndromes such as Apert syndrome, Poland syndrome, and Saethre-Chotzen syndrome. Environmental factors during pregnancy may contribute to risk, including exposure to certain medications like thalidomide, maternal smoking, and alcohol consumption. In many cases, syndactyly occurs without any identifiable cause as an isolated birth defect. The condition affects approximately 1 in 2,000-3,000 live births, with males slightly more affected than females, and is more common in white populations. The webbing most frequently occurs between the third and fourth fingers or the second and third toes.
Some key points to consider:
- Genetic factors play a significant role in the development of syndactyly, with both inherited and spontaneous genetic mutations contributing to the condition 1.
- Family history is an important risk factor, with a 50% chance of inheriting the condition if one parent has it.
- Environmental factors during pregnancy, such as exposure to certain medications or maternal smoking, may also contribute to the risk of syndactyly.
- Syndactyly can occur as part of genetic syndromes, such as Apert syndrome or Poland syndrome.
- The condition affects approximately 1 in 2,000-3,000 live births, with males slightly more affected than females.
It's worth noting that while there are various studies on syndactyly, the most recent and highest-quality study 1 provides the most reliable information on the causes and risk factors of the condition. This study highlights the importance of genetic factors in the development of syndactyly and provides valuable insights into the risk factors and characteristics of the condition. By prioritizing the most recent and highest-quality study, we can ensure that our understanding of syndactyly is based on the best available evidence.
From the Research
Causes of Syndactyly
- Syndactyly can be caused by multiple familial or spontaneous genetic abnormalities, which typically involve the canonical wingless-type (WNT) pathway 2
- It may occur as an isolated entity or a component of more than 300 syndromic anomalies 3
- At least nine non-syndromic syndactylies with additional sub-types have been characterized, with most being inherited as autosomal dominant, but two autosomal recessive and an X-linked recessive entity have also been described 3
Risk Factors for Syndactyly
- The severity of the malformation depends on the fusion level, the tissues involved in the union, and whether it is isolated or syndromic 4
- The prognosis for these deformities directly depends on their severity, with excellent outcomes in cases of cutaneous fusion, and much less predictable ones when osteoarticular and/or tendinous tissues are involved 4
- The degree of deformity also affects the ultimate outcome of surgical treatment and rehabilitation 5
Classification of Syndactyly
- Syndactyly can be categorized as simple, involving just the skin and soft tissue, or complex, involving the phalanges 2
- It can also be categorized as complete, involving the entire digit (including the nail fold), or incomplete, which does not involve the nail fold 2
- A 'current classification scheme' has been presented, based on an overview of well-characterized isolated syndactylies, their cardinal phenotypes, inheritance patterns, and clinical and genetic heterogeneities 3