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Understanding the difference between syndactyly and polydactyly helps you know what to expect and how to support your baby’s development.
What is Syndactyly?
Syndactyly happens when two or more fingers or toes are fused or webbed together. This occurs during early pregnancy, around the 6th to 8th weeks, when the digits don’t fully separate as they develop. It’s fairly common, and it’s more likely to happen in boys than girls. Types of Syndactyly
The fusion can vary:- Simple syndactyly: Only skin connects the digits.
- Complex syndactyly: Fusion involves shared bones, nerves, or blood vessels.
It may affect:
- One hand or foot (unilateral)
- Both hands or feet (bilateral)
Impact
If the fused digits are of different lengths, it could limit finger growth or function. Simple things like holding or picking up objects might feel harder.For toes, it’s often more of a cosmetic concern, but it could affect wearing shoes comfortably.
Causes
Syndactyly can happen by chance, be inherited, or, be part of a syndrome with other symptoms.Sometimes, it’s linked to genetic factors, like an autosomal dominant trait. This means there’s a 50 per cent chance a child inherits it if one parent carries the gene.
What is Polydactyly?
Polydactyly means your baby has an extra finger or toe. This can vary from a small, soft tissue tag to a fully formed, functioning digit. It’s another congenital deformity.Types of Polydactyly
Polydactyly is classified into two main types:- Preaxial: An extra digit near the thumb.
- Postaxial: An extra digit near the little finger.
Impact
Polydactyly usually doesn’t cause functional problems, but an extra thumb might affect how your child uses their hand. The extra digit is usually removed for cosmetic or functional reasons.Causes
Like syndactyly, it’s often genetic with a 50 per cent chance of passing from a parent with the autosomal dominant trait. It can also occur randomly or be linked to syndromes or toxic exposures during pregnancy.What is the Difference Between Syndactyly and Polydactyly?
Both syndactyly and polydactyly are congenital hand or foot differences, but they’re opposites in a way.In syndactyly, two or more fingers or toes are joined together. In polydactyly, there is an extra finger or toe. Sometimes both can occur at the same time in a condition called polysyndactyly, where the extra finger or toe is also joined.
Syndactyly might affect your child’s ability to use their hand if it involves complex fusion, whereas polydactyly is often more about appearance unless it involves the thumb.
How Are Syndactyly and Polydactyly Diagnosed?
Both conditions are usually noticeable at birth because your baby’s hands or feet will look different. Doctors can also spot these conditions during pregnancy using an ultrasound.If your baby has either condition, the doctor will check whether it is isolated or part of a syndrome. Syndactyly can be linked to Poland’s Syndrome or Apert Syndrome, while polydactyly can be linked to Meckel Syndrome. This evaluation might include X-rays to understand the structure of the affected digits.
How Are Syndactyly and Polydactyly Treated?
Treatment for both conditions involves surgery, but the type of surgery and the right time for it depend on your baby’s condition.Most surgeries are planned after 6 months of age, often between 1 and 2 years. This age is safer for your child to undergo general anaesthesia and their hand or foot is developed enough.
Syndactyly Treatment
Surgery aims to separate the fused digits to improve function and sometimes appearance. The surgeon makes zig-zag incisions to create a new web space and may use skin grafts from the groin to cover gaps.If multiple digits are fused, more than one surgery might be needed to avoid damaging the blood supply.
Polydactyly Treatment
Surgery removes the extra digit, which could be a simple procedure for a soft tissue tag or more complex if the digit has bones or joints.For preaxial polydactyly (extra thumb), surgeons might combine parts of both thumbs to create one functional thumb.
Emergency surgery might be needed if an extra digit twists and risks tissue damage (gangrene).
What to Expect After Surgery?
This is what you can expect after your child’s surgery:- Their hand or foot will be covered with bandages to protect the healing skin, especially if skin grafts were used.
- Their limb needs to be kept elevated to reduce swelling and pain.
- You should regularly check the visible fingertips or toes for warmth, colour, and movement to confirm good blood flow.
- Follow-up visits with the doctor will track healing and check for issues such as scarring or webbing (when the skin between separated fingers or toes slowly grows back, causing them to partly join again).
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FAQs on Syndactyly Vs Polydactyly: How They Differ and What They Mean for Your Baby
- What is type 4 syndactyly?
Type 4 syndactyly is a rare congenital condition where all fingers are completely fused on both hands, often with extra digits. This fusion gives the hand a cup-shaped appearance. - Is polydactyly linked to autism?
Polydactyly can be linked to autism, but only in rare genetic disorders where the same mutation causes both extra digits and autism-related symptoms.
