Polydactyly: Causes, Symptoms & Treatment

Polydactyly describes the existence of more than five fingers on a hand or more than five toes on a foot. Through an autosomal dominant inheritance, the affected individual inherits this deformity from one parent. Polydactyly exists in various classifications and expressions.

What is polydactyly?

The term polydactyly is used in medicine to describe extra fingers or toes in the upper or lower extremities. The anomaly is present at birth and is therefore a congenital condition. It is caused by increased longitudinal segmentation during the embryonic period. The additional toes and fingers can be differently pronounced. Both shape and size as well as localization can vary enormously. These can be approximately very small and non-functional as well as existing only as skin flaps. A large addition usually has a complete bone structure and skeletal connections. Polydactyls very often occur bilaterally and mostly in the upper extremities. An anomaly on only one foot or only one hand is less common, but also possible. Classification can be made according to localization. On the side of the hands, a distinction is made between radial, ulnar, and central:

  • Radial, when the extra finger is next to that of the thumb. So in this case, it is a thumb duplication.
  • Ulnar, if this is present next to the little finger.
  • Central between the second to fourth fingers.

Polydactyly can occur in both humans and animals.

Causes

In most cases, the cause of polydactyly is autosomal dominant inheritance. Different mutations can be passed to the child and manipulate the control of expression of a gene. The variety of mutations is responsible for the different localizations and forms. During embryonic development in the mother’s womb, the embryo‘s hands initially have the shape of a paddle. Only after the sixth week of gestation does the surface of the paddle split into separate fingers. This process is possible with the help of apoptosis, the programmed death of body cells. Accordingly, the unnecessary cells between the fingers are driven to self-destruction. Irregularities during this phase can form polydactyly. This anatomical anomaly occurs when one finger splits into two. Advanced maternal age or elevated testosterone levels during pregnancy increase the risk. Alternatively, polydactyly may be one of the many accompanying symptoms of various syndromes. It is often observed in Ellis-van-Crevelt syndrome, Bardet-Biedl syndrome, Carpenter syndrome, and Down syndrome. As well as in trisomy 13 and 18.

Symptoms, complaints, and signs

Because toes or fingers are abundant in polydactyly, the foot or hand is disseminated. A widened forefoot can be problematic when acquiring footwear. There may also be difficulties in locomotion and maintaining body balance. This can eventually lead to back and hip problems. Additional structures can cause spatial constraints and axis deviations in the foot space. Centrally located polydactyls are particularly affected by this problem. If there is not enough free space between the adjacent toes and fingers, impression marks and excessive sweating can occur. Possible consequences on the feet are corns, fungal infections, calluses, blisters and unpleasant foot sweat odor. If the additional structure is particularly large and affects the entire tissue, it can form severe bone deformities. Such as the hallux varus or hallux valgus. In addition, those affected complain of aesthetic discomfort. Polydactyly is enormously noticeable and appears strange. The deformity can also be extremely pronounced.

Diagnosis and course of the disease

If the foot or hand is affected by a giant growth, polydactyly is uncomplicated to detect with the naked eye. In this case, the findings are clinically very clear. Minimal formation, height, and shape can be diagnosed with an x-ray. Sonography can identify polydactyly as early as the fourteenth week of pregnancy.

Complications

Those affected by polydactyly suffer from extra fingers or extra toes on the feet.As a rule, polydactyly does not pose any particular health risk, so that the patient’s life expectancy is usually not negatively affected by the disease. However, it can lead to various complaints and restrictions in the patient’s everyday life, so that familiar activities can sometimes no longer be carried out without further ado. Furthermore, in addition to the extra fingers or toes, patients also suffer from discomfort in the hip or back. This can also lead to restrictions in movement under certain circumstances. Polydactyly also leads to excessive sweat production and further to unpleasant odors or fungal infections. The patient’s quality of life is therefore significantly reduced by this disease. Without treatment, deformations of the bones also occur, which are usually associated with pain. The extra toes or fingers can be removed by surgical procedures. No complications occur in this process. The other symptoms can also be limited and alleviated with various therapies.

When should you go to the doctor?

Polydactyly should always be evaluated by a doctor. There is no self-healing in this disease. The symptoms significantly limit the life of the affected person, so treatment can significantly improve the quality of life. A doctor should be consulted for this disease if the affected person has an excessive number of toes or fingers. The extra toes or fingers can occur either on both limbs or only on one of the limbs, making life more difficult. The doctor should also be consulted if the polydactyly causes a strong secretion of sweat or if blisters and corns form on the limbs. A psychologist can also be consulted if there are psychological complaints due to the limited aesthetics, as bullying and teasing can occur, especially in children. Polydactyly can be diagnosed by a general practitioner or by a pediatrician. Further treatment is then usually surgical without complications. The patient’s life expectancy is also not negatively affected by this condition.

Treatment and therapy

Surgical treatment can be performed to improve aesthetics and function. The extra fingers and toe are thus removed. Many other corrections are required and ensure the comfort and usability of the hand or foot. Movable skin appendages are usually tied off shortly after birth and fall off. In the case of thumb duplication, surgery from the eighth month of life is optimal. However, restricted movement and joint instability often follow. In some cases, nail deformity develops. The outcome often depends on the severity of the anomaly. The greater the deformity, the more likely it is to require follow-up correction. Central polydactyly is treated surgically in the first or second year of life. This prevents contracture and deviation. Postoperative unfavorable vascular distribution can lead to circulatory disturbances with subsequent necrosis. The result is usually very poor with many subsequent corrections. If the parents of the affected child decide against surgical treatment, the appropriate footwear must be orthopedically made from the beginning of the walking age. The foot must have sufficient space to counteract skin diseases and further bone deformations. Special shoe inserts are most likely required as well.

Prevention

Because polydactyly is an autosomal dominant inherited disorder, no preventive measures exist. If one parent is affected by this anatomical feature, there is a fifty percent risk for offspring to inherit it as well. However, the structure can be detected by sonography from the fourteenth week of pregnancy.

Follow-up

In most cases, no special or direct measures of aftercare are available to affected individuals with polydactyly. However, affected individuals should ideally see a doctor at an early stage to avoid further complications or limitations in everyday life. The disease itself does not always need to be treated. In most cases, patients are dependent on surgical intervention, which can alleviate the symptoms.In any case, the patient should rest and take care of his body after such an operation. Here, efforts or other stressful and physical activities are to be refrained from in order not to stress the body unnecessarily. If polydactyly occurs on the feet, special shoes and insoles can also be used to counteract the discomfort. Likewise, regular checkups and examinations by a doctor are very important. In children, parents should recognize the signs and symptoms of polydactyly early and then consult a doctor. Further measures of aftercare are usually not available to the patient and are not necessary in this case.

What you can do yourself

Polydactyly does not necessarily require medical treatment. The most important self-help measure is to avoid exposing the affected limb to further stress. This can be achieved, for example, by wearing a special bandage that fixes the supernumerary limb. After surgery, the affected hand should initially be rested. Physiotherapy and physical therapy support recovery by optimizing the mobility of the remaining fingers. Polydactyly is not a serious condition and therefore does not require any further measures. After the supernumerary limbs have been surgically removed, the majority of patients are symptom-free. Nevertheless, the affected hand or foot should be monitored. If inflammation occurs or other unusual symptoms appear, the physician must be informed. If the optical blemish has a negative effect on the mental condition, the doctor must be informed. Usually a psychological discussion with a therapist is sufficient to overcome the insecurity. In the case of severely pronounced polydactyly, in which seven or more fingers or toes appear on one hand or foot, further medical measures may be necessary. The patient should contact the appropriate orthopedic surgeon and discuss appropriate self-help measures such as range-of-motion exercises or muscle relaxation.