Ectrodactyly: Lobster claw syndrome

Ectrodactyly is a rare congenital deformity of the hand where the middle digit is missing, and the hand is cleft where the metacarpal of the finger should be. This split gives the hands the appearance of lobster claws. And hence the known as the lobster claw syndrome.

But ectrodactyly patients can have any number of unusual arrangements of the digits. Ectrodactyly is an inherited condition which can be treated surgically to improve function and appearance.

It often occurs in both the hands and the feet. This syndrome is also called Split hand/foot malformation (SHFM). The person affected with this disease often faces social stigmatization due to the malformed digits.

Symptoms of Ectrodactyly (Lobster Claw Syndrome):

Gene

This rare syndrome has many forms and varies from person to person.  One of the most common of this forms called Type I is associated with a specific region of human chromosome 7 that contains two homeobox genes, DLX5 and DLX6. These genes are similar to a gene in insects called distal-less that controls limb development.

When this gene is defective in the fruit fly the distal part of the insect limb is missing. It was therefore assumed that DLX5 and DLX6 might have conserved this function through evolution and could have a role in vertebrate limb development. However, in spite of intensive searches for mutations of these genes in SHFM patients, no direct evidence was found to date on their involvement in mammalian limb development.

In olden days, a person diagnosed with ectrodactyly usually ended up joining a circus sideshow, and used his deformities to his favor. The syndrome affects males and females equally.

Cause:

gene

Most cases of Ectrodactyly happen owing to mutations of the TP63 gene. These mutations are either spontaneous or new or inherited as autosomal disorders. The abnormal gene present as a dominant gene either in the father or mother is inherited by the child. The risk of inheritance of TP63 gene is 50% in pregnancy irrespective of the sex of the offspring.

The TP63 gene contains instructions for producing a protein essential for the normal development of limbs and other structures. Owing to mutation, the functional level of p63 protein gets reduced causing malformation of body structures.

Personalities with Lobster Claw Syndrome:

lobster-boy

Image Source : assets.rebelcircus.com

The Lobster Boys, Grady Stiles Sr. and Grady Stiles Jr., for instance. Apart from the Lobster Boys, the most famous personality to have ectrodactyly syndrome is Bree Walker. She is a news anchor for 20 years with KCBS news in Los Angeles and an actress on HBO drama Carnivale. She also appeared in the fourth season premiere of FX’s Nip/Tuck playing a real estate agent counseling parents expecting a child with ectrodactyly.

Treatment:

Surgery

This condition can however be cured to some extent surgically. And one such case is of Sisters Samantha and Stephanie Wojciechowicz. When the girls were 2 years old they were operated upon by Dr. Joseph Upton, and the result was life changing.

Medical science is continuously keeping an eye on this syndrome and is not leaving any stone unturned to go to the roots of its cause.

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