Cardiofaciocutaneous syndrome Health Article

Definition

Cardiofaciocutaneous syndrome is an extremely rare genetic condition present at birth and characterized by mental retardation, slow growth, and abnormalities of the heart, face, skin, and hair. There is no cure for cardiofaciocutaneous syndrome. Treatment centers on the correction of heart abnormalities and strategies to improve the quality of life of the affected individual.

Description

Cardiofaciocutaneous syndrome was first identified and described in 1986 by J. F. Reynolds and colleagues at the Shodair Children's Hospital in Helena, Montana and at the University of Utah. These physicians identified and described eight children with a characteristic set of mental and physical changes including abnormal skin conditions, an unusual face, sparse and curly hair, heart defects, and mental retardation. These physicians named the syndrome based on the changes of the heart (cardio), face (facio), and skin (cutaneous). Since that time, physicians have used the descriptions originally put forth by Dr. Reynolds to identify other children with cardiofaciocutaneous syndrome.

Scientific research conducted over the past decade suggests that cardiofaciocutaneous syndrome is associated with a change in the genetic material. However, it is still not known precisely how this change in the genetic material alters growth and development in the womb to cause cardiofaciocutaneous syndrome.

Cardiofaciocutaneous syndrome can sometimes be confused with another genetic syndrome, Noonan syndrome. Children with Noonan syndrome have abnormalities in the same genetic material as those with cardiofaciocutaneous syndrome, and the two syndromes share some similar physical characteristics. Many scientists believe that the two diseases are different entities and should be regarded as separate conditions, while others believe that Noonan syndrome and cardiofaciocutaneous syndrome may be variations of the same disease.

Genetic profile

Recent research has shown that people with cardiofaciocutaneous syndrome have changes in a gene located on a region of human chromosome 12 (locus 12q24), but the precise gene and genetic alteration is unknown.

In almost all cases of cardiofaciocutaneous syndrome, there is no family history of the disease. These cases are thought to represent new genetic changes that occur randomly and with no apparent cause and are termed sporadic. While the cause of the genetic change is still unclear, some studies suggest that the age of the father might be important in the genesis of the disease. In 20 cases for which information was available, scientists noted that fathers of affected children tended to be older (average age of 39 years) when the child was conceived. Therefore, it is believed that a change in the genetic material of the father's sperm may occur as the man ages, and that he may, in turn, pass this genetic change to the child, resulting in cardiofaciocutaneous syndrome.

Only one abnormal gene in a gene pair is necessary to display the disease. This is an example of a dominant gene (i.e. the abnormal gene of the gene pair dominates over the normal gene, resulting in the syndrome).

Demographics

Cardiofaciocutaneous syndrome is an extremely rare condition. Because the syndrome is relatively new and only a small number of physicians have actual first-hand experience with the diagnosis of the syndrome, some children with the syndrome may not be diagnosed, particularly if they are living in areas where sophisticated medical care is not available. As a result, it is difficult to know how many children are affected by cardiofaciocutaneous syndrome. However, scientists estimate that less than 200 children worldwide are presently affected by this condition.

Because the syndrome is so rare, it is not known whether the disease is distributed equally among different geographic areas or whether different ethnic groups have higher incidences of the syndrome.

Signs and symptoms

Individuals with cardiofaciocutaneous syndrome have distinct malformations of the head and face. An unusually large head (macrocephaly), a prominent forehead, and abnormal narrowing of both sides of the forehead (bitemporal constriction) are typical. A short, upturned nose with a low nasal bridge and prominent external ears that are abnormally rotated toward the back of the head are also seen. In most cases, affected individuals have downward slanting eyelid folds, widely spaced eyes, drooping of the upper eyelids, inward deviation of the eyes, and other eye abnormalities. In addition to having unusually dry, brittle, curly scalp hair, affected individuals may lack eyebrows and eyelashes.

Individuals with cardiofaciocutaneous syndrome may also have a range of skin abnormalities, varying from areas of skin inflammation to unusually dry, thickened, scaly skin over the entire body. Most affected individuals also have congenital heart defects, particularly obstruction of the normal flow of blood from the right chamber of the heart to the lungs and/or an abnormal opening in the wall that separates two of the heart chambers.

In addition, most individuals with the disorder experience growth delays, mild to severe mental retardation, and abnormal delays in the acquisition of skills requiring the coordination of muscular and mental activity. Other abnormalities encountered in children with cardiofaciocutaneous syndrome include seizures, abnormal movements of the eye, poor muscle tone, and poor digestion. In some cases, additional abnormalities may be present.