Phocomelia

What is the

phocomelia?

The focomelia is an extremely rare congenital skeletal disorder which affects the extremities characteristic way from birth. The bones of the upper extremities are severely shortened or absent and the fingers may be attached.

In extreme cases, both the bones of the upper and lower extremities are absent, so that the hands and feet are attached to the body, directly forming what is known as tetraphocomelia.

Like other malformations, it is the consequence of alterations in embryonic development. Children with phocomelia need surgery, as other pathologies develop alongside this disorder.

Those affected with phocomelia have a high mortality rate. Mildly affected individuals can survive to adulthood.

Symptoms

-Underdeveloped limbs and absence of pelvic bones. The upper extremities are usually not fully formed and parts of the hand may be missing. Short arms, fused fingers, and missing fingers are often the most notable consequences.

-The lower extremities also usually show symptoms similar to the upper extremities.

-Phocomelia can also cause mental deficiencies in children. Newborns tend to have a smaller head than children without the disorder and sparse hair with a “gray” gray appearance.

-The pigments in the eyes of the affected person usually have bluish tones.

-Undeveloped noses, disfigured ears, irregularly small mouths (micrognathia) and cleft lip are also usually present.

-It also presents other defects such as large genitalia, congenital heart disease and cystic kidneys.

Some of these conditions are usually diagnosed at birth or even earlier, while others may go unnoticed and develop later in life, necessitating treatments such as reconstructive surgery.

It is difficult to summarize the symptoms that can occur in a phocomelia syndrome, since the spectrum encompasses an abysmal number of organs and tissues, all of which are directly affected in their embryonic development.

Causes

Although several environmental factors can cause phocomelia, the main causes come from the use of thalidomide and genetic inheritance.

Inheritance

Families can carry recessive genes that are passed on to a child who may in turn develop the condition. The inherited form of phocomelia syndrome is transmitted as an autosomal recessive trait with variable expressiveness and the malformation is linked to chromosome 8.

It is of genetic origin with a Mendelian inheritance pattern, which presents with multiple congenital malformations and a premature separation of centromeric heterochromatin from the chromosomes in 50% of cases.

The genetic form of this disease is seen less frequently than its pharmacological counterpart, since being autosomal recessive in nature, genes tend to be transmitted from generation to generation in these families, but rarely become clinically manifested.

Incest can precipitate a future generation with overt phocomelia, as the transmission of the same gene from both parents increases the chances that this weak (or recessive) gene will express itself physically (or phenotypically).

Thalidomide

Cases of drug-induced phocomelia syndrome may be associated primarily with maternal ingestion of thalidomide by pregnant women.

In the middle of the last century, cases of phocomelia increased dramatically due to the prescription of thalidomide.

They were prescribed to relieve morning sickness and were found to have teratogenic effects; the ability to generate clearly visible malformations. The observed malformations caused by thalidomide ranged from hypoplasia of one or more digits to the total absence of all the extremities.

Thalidomide was recognized as a cause of serious congenital deformities and was withdrawn from the market worldwide between 1961 and 1962.

Current incidence

The current incidence of phocomelia is 1 to 4 in 10,000 babies. Despite the fact that the number of babies has been significantly reduced due to the elimination of thalidomide in the treatment during pregnancy, there is still genetically induced phocomelia.

Finally, there are infections that can occur during pregnancy that can affect the baby and manifest as focomelic syndrome.

The most common example that exists today is chickenpox in pregnant women, caused by the same virus that causes it in healthy people, the varicella zoster virus.

In this case, it is also characteristic to observe babies with congenital cataracts in the eyes and alterations in the shape of the skull.

Treatments

There is no treatment, but the enabling of body movements and adjustment to daily activities, and also the use of prostheses to facilitate functioning.

The resulting lack of nerves and bone tissue leaves surgeons with very little to work on during reconstruction, which is why very few surgeries are performed on children or adults with these types of limb malformations.

However, surgery can be useful to correct positional abnormalities of some bones and joints or to control some signs and symptoms associated with the disorder.

Treatment for phocomelia syndrome is often planned while the child is an infant and focuses on the severity of the affected individual’s symptoms. Most treatment for phocomelia syndrome is supportive, allowing the baby to live a more normal life.

Myoelectric prostheses have produced revolutionary results due to the number of functions they provide without wiring. The limbs move when they are connected to the prosthesis through nerves, which send movement signals.

There is also the possibility of grafting bones from other parts of the body to the upper extremities to increase the usefulness of the hands. However, the correction is not complete due to the absence of blood vessels and nerves that are necessary for movement.

Other common treatments are the use of braces and therapies to treat any delays in speech, cognitive and language. Psychological support for babies and children with phocomelia is of great importance, especially if the child has a mental disability.

References

  1. Dr. Karim Mukhtar, (2013), Anesthesia recommendations for patients suffering from Phocomelia, OrphanAnesthesia: orpha.net
  2. Dr. Mrs. Gayatri S. Chakre, (2012), Phocomelia Syndrome – A Case Report: jkimsu.com
  3. Alejandro Medina-Salas, Cecilia Alejandra Carranza-Alva, (2012), Roberts syndrome: a case report, Mexican Journal of Physical Medicine and Rehabilitation: medigraphic.com
  4. Phocomelia – Shortened or Absent Arms or Legs, sf, BabyMed: babymed.com
  5. Phocomelia, nd, anencefalia.org: anencefalia.org

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