What Is Phocomelia Syndrome?
Phocomelia Syndrome (PS) also known as (SC Phocomelia Syndrome, Pseudo-Thalidomide Syndrome, Roberts SC-Phocomelia Syndrome, and Roberts Tetraphocomelia Syndrome) is a very rare congenital birth defect that causes extreme defects of the infant, especially in relation to his or her upper extremities. Often, the bones of the arms or other appendages are notably shortened or absent. Fingers may be fused together, and in very severe cases of Phocomelia Syndrome, the infant is born with tetraophocomelia, or without bones to the upper arms and legs, so that the hands and feet are directly attached to the torso of the body.
Phocomelia Syndrome can be the result of autosomal recessive traits from genetic transmission between family members, or it may occur as a result to a random change in the gene. Phocomelia Syndrome very closely mimics the disorder caused by prenatal ingestion of thalidomide and is often called "pseudo-thalidomide."
The inherited form of Phocomelia Syndrome is extremely rare - affecting only approximately twelve babies each year, PS affects males and females in similar ratios.
What Causes Phocomelia Syndrome?
The inheritable form of Phocomelia Syndrome is a genetic disorder that is transmitted by an autosomal recessive trait on chromosome 8 at gene map locus 8p21.1.
Genetic disorders are the result of a combination of genes for a certain trait on a chromosome received by the mother or father.
Genetic disorders caused by recessive traits happen when a person inherits an abnormal gene from each parent, such as the case with the inheritable form of Phocomelia Syndrome. If a person inherits a normal copy of a gene from one parent and an abnormal copy of the gene from the other, the person is considered a "carrier" for that genetic disorder, but is generally asymptomatic.
Read more about genetic disorders.
Phocomelia Syndrome may also be the result of certain drugs taken prenatally or as the result of unknown circumstances. Both the drug thalidomide, which was used to treat severe morning sickness, and Accutane, a drug used to treat acne, can also cause birth defects like Phocomelia Syndrome.
What Are The Symptoms of Phocomelia Syndrome?
While there are many symptoms of Phocomelia Syndrome, the most notable symptom is that of the deficiency of the limbs of the upper body; although, it's important to note that the limb defects are variable. The most common symptoms of Phocomelia Syndrome include:
- Often, the upper limbs are most affected while parts of the hands or arms are malformed or absent.
- Development of the legs and feet may be present.
- The limbs (hands or feet) may be closely attached to the torso.
- Limbs may be abnormally small.
- Intrauterine growth deficiencies may occur.
- Infant growth may be stunted or slowed.
- Cognitive development may be affected.
- Hair may be a very light blond and sparse upon the head.
- Head may be abnormally small (microcephaly).
- A hemangioma (swelling or mass of blood vessels) may be present upon the face.
- Eyes are often wide-set and have blue-tinged sclera.
- The nose may be small and underdeveloped with very thin nostrils.
- Cleft lip - with or without cleft palate - may also be evident.
- Micrognathia - a smaller jawbone structure.
- Cryptorchidism - undescended testicles may occur in male infants.
Less common symptoms of Phocomelia Syndrome may include:
- Encephalocele - a gap in the skull with or without brain herniation
- Hydrocephalus - excess accumulation of cerebrospinal fluid, that can cause headaches, small eyeballs, seizures, and vomiting
- Hypospadias - the urethra may open underneath the penis or the into vagina
- Bicornate uterus
- Short neck
- The corneas of the eye may be cloudy, have cataracts, and eyelid defects may be present
- Kidney abnormalities
- Heart defects
How Is Phocomelia Syndrome Diagnosed?
Generally speaking, Phocomelia Syndrome is usually diagnosed on a prenatal ultrasound of the fetus. While not a 100% success rate at diagnosis, ultrasounds are often reliable enough to suggest further testing. If not detected in utero, a physical examination of the infant can diagnose Phocomelia Syndrome.
Unfortunately, there are no existing definitively accurate prenatal tests for Phocomelia Syndrome available.
How Is Phocomelia Syndrome Treated?
Treatment for Phocomelia Syndrome are often planned while the child is an infant and focuses upon the severity of symptoms of the affected individual. Most of the treatment for PS is supportive, allowing the infant to live a more normal life. Treatment for PS may include the following:
- Artificial limbs may be used to replace any missing or shortened extremities
- Prosthetic appliances may be used for missing teeth
- Orthopedic braces
- Orthopedic appliances
- Therapies to treat any speech, cognitive and language delays
- Genetic counseling for the child and the family to ascertain if PS is genetically inherited or the result of an unknown mutation
Additional Phocomelia Syndrome Resources:
US Clinical Trials - US government's database of ongoing clinical trials for a variety of rare - and not so rare - disorders.
National Rehabilitation Information Center - online gateway to an abundance of disability- and rehabilitation-oriented information organized in a variety of formats designed to make it easy for users to find and use.