There are today over 300 forms of dwarfism, achondroplasia is one of them. Achondroplasia is the most common form of short stature. It occurs in approximately 1 in 26,000 to 1 in 40,000 births. The characteristic features of achondroplasia are apparent at birth. These include typical facial features, disproportionate short stature, and rhizomelic (the proximal ends of the limbs) shortening. Diagnosis of achondroplasia is made by physical exam and skeletal x-rays. Most individuals have normal intelligence. Infants and children often have motor delays but cognitive delays are not present.
Final adult height is in the range of about 100 to 135 cm.
The facial features include a large head with a prominent forehead. The midface is often small with a flat nasal bridge and narrow nasal passages. In infancy and childhood, middle ear infections often occur because of the small nasal passages and Eustachian tube dysfunction. If the ear infections are left untreated, hearing loss can occur. "Ear tubes" are probably indicated for a child with multiple ear infections. The jaw appears to be prominent. Occasionally dental crowding can occur since the jaw is small.
Respiratory problems can occur in infants and children. Airway obstruction can be "central" in origin (due to foramen magnum compression) or "obstructive" in origin (due to narrowed nasal passages). Symptoms of airway obstruction include snoring, sleeping with the neck in a hyperextended position, or apnea. A sleep study is done if these symptoms exist to determine the cause of the airway obstruction. Treatment depends on the type of obstruction. If central obstruction is present, a foramen magnum decompression is performed. If obstructive airway obstruction is present, therapy can include tonsillectomy, adenoidectomy, or tracheostomy placement.

Achondroplasia is an autosomal dominant condition . This means that a person with achondroplasia has a 1 in 2 or 50% chance of having children with achondroplasia. However, approximately 75% of individuals with achondroplasia are born at parents with average size. In these cases, achondroplasia is due to a new mutation or genetic change. The gene for achondroplasia has been found. It is called FIBROBLAST GROWTH FACTOR RECEPTOR (FGFR3). It is often seen, that two individuals with achondroplasia have children. (Not in Denmark while there are only about 500 with dwarfism) Those couples risk having a child with 2 copies of the changed gene, or double homozygosity. Infants with homozygous achondroplasia are either stillborn or die shortly after birth. Couples at risk often have prenatal diagnosis via serial ultrasounds. A DNA test is now also available to detect double homozygosity.
Today, it is possible to treat people with short stature, so they can become a few cm. higher. The possible treatments are either with hormones, or the legs can be extended by surgical interference.

Hereditary of having a child whit achondroplasia
Couples where none of the parents have achondroplasia
Couples where one of the parent have achondroplasia
Couples where both of the parents have achondroplasia

0 % chance for Achondroplasia

50% chance for Achondroplasia

75% chance for Achondroplasia

SOURCE:  Greenberg Center for Skeletal Dysplasias

In United States there is a lot of knowledge about achondroplasia, and the treatment forms for people who wants to be higher. They have the largest organization in the world, for people with short stature. LPA (Little People of America) you can read more about them, on the site Web-Sites. Here is also links to other Web-Sites about achondroplasia.
This page was last edited 02. april 2000