Progeria. Hutchinson-Gilford Syndrome.
Incidence
Probably autosomal dominant with rare instances of affected sibs due to germinal mosaicism. Progeria affects approximately one out of every eight million children, with only a few hundred cases seen worldwide. Signs usually first develop between the age of 6 and 12 months, though the disease occasionally does not develop until 2 years of age or later. Nearly 97% of all children with the disease are Caucasian, and slightly more males than females develop the disease. There is a paternal age effect.
Clinical Characteristics
Progeria is an extremely rare genetic disease that results in rapid aging, beginning early in childhood. The aging process of progeria very closely resembles normal human aging except that it occurs in the very young. At an early age, the children affected by this disease develop many of the problems usually not seen till much later in life, such as atherosclerosis (clogging of the arteries), baldness, cardiovascular disease, loss of subcutaneous fat, and joint stiffness. Children with progeria appear perfectly healthy at birth. Typically, the first signs of the disease appear between 6 and 12 months when the child fails to gain weight and his/her skin starts to become thick and inelastic, particularly on the arms, legs, and hips. Scalp hair and eyelashes are then progressively lost, usually progressing to complete baldness. At about the same time, much of the body\\\'s fat is lost. As a result of this loss of hair and subcutaneous fat, many of the body\\\'s veins become prominent, particularly those on the scalp. Children with progeria usually will also not grow to a full height, will develop thin limbs with prominent joints, and will have a small jaw (micrognathia). As the disease progresses, individuals with progeria develop widespread thickening and loss of elasticity of the artery walls, severe joint stiffness similar to that of arthritis, and frequent hip dislocations. A few children have been reported who have muscle weakness as well, and the disease is related to a form of muscular dystrophy. However, most children do not have muscle problems. Children with progeria have normal intellectual capabilities and can learn just as well as (if not better than) other children of their same age and also demonstrate the same range of emotions and feelings as other children. They do often remain very reserved in the presence of strangers, however, because they are aware very early on in life that they appear very different than their peers. Progeria is caused by a change in the lamin A (LMNA) gene. This mutation causes the gene to make an abnormal form of the lamin A protein. This abnormal protein seems to destabilize the membrane surrounding the nucleus of cells. It is thought that this loss of stability contributes to many of the symptoms of the disease. There seem to be several other genes that contribute to the symptoms of the disease, but these have not yet been identified. It is unclear at this point how exactly the changes in the lamin A lead to the typical disease symptoms. This change is not believed to be passed down from parent to child and is thought to occur at random. Nothing is known to cause the change in the gene, nor is anything known to prevent it. Progeria is a disease that continually worsens with no treatment that has yet been proven effective in slowing this progression until recently (using lonafarnib). The average life expectancy of a child diagnosed with progeria is 13 years, but some children with the disease have died as early as 7 and some have survived till the age of 27. Over the course of the disease, the child\\\'s heart and circulatory abnormalities become progressively worse and are usually the most significant health problem for children with progeria. These children usually die from cardiovascular problems such as atherosclerosis, but some have died due to convulsions or various types of malnutrition.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
A genetic test was recently developed that can test for and diagnosis progeria. Prior to the development of this test, the disease was diagnosed based solely on the physical symptoms mentioned above. With the genetic test, children can be diagnosed at a much earlier age than they were before the test was available, allowing an earlier start to treatment.