Genetic Testing for Achondroplasia

Submitted on March 27, 2012

What Is Achondroplasia?

Achondroplasia is a rare kind of genetic disorder which, although it develops as the child grows, is evident even at the time of birth. The occurrence of this genetic disorder is very rare and it is estimated that its incidence is only about 1 in 40,000 births. The disorder is not specific to any sex or race and manifests itself right from birth. There are evidences of this disorder in the art depiction of the oldest of paintings of the Egyptian civilization, making this one of the oldest ever congenital disorders.

Though rare, achondroplasia is the commonest group of disorders that are characterized by abnormally proportionate body parts. In this disorder, it is typical to have a normally grown torso, with both arms and legs abnormally short. In fact, the etymology of the term 'achondroplasia' itself is an indicator of the kind of disorder this is. In Greek, the term literally means; without cartilaginous formations. However, though in reality, those suffering from this disorder do have cartilage in their body, in a few places of the body, cartilage doesn't develop at all.

At birth, our bone structure is cartilaginous and the cartilage keeps turning into bones as we grow. However, in those who suffer from this disorder, the cartilage takes a lot of time turning into bones, because of which the person experiences a short stature and largely stunted growth.

Typically, a child suffering from this disorder would have a normal trunk, but as compared to the torso, the arms and the legs appear rather disproportionately small. The upper arms and the thighs especially, are shorter than they ought to be. The head may also appear larger as compared to the rest of the body. The forehead too appears to be abnormally large and the nose may not have a properly formed bridge, because of which it too appears to be abnormal.

Diagnosis of Achondroplasia Genetic Testing

Since this is a genetic disorder, the best way to diagnose it is genetic testing for achondroplasia. If a child has already been born, test for achondroplasia includes a physical examination and an x-ray to see the skeletal structure of the baby. Achondroplasia genetic testing still seems to be the best test for this disorder. This genetic testing is done through a blood analysis. Prenatal testing for achondroplasia is done by performing an ultrasound. The ultrasound is usually able to show whether the bones are forming normally or not. If the ultrasounds finds anomalies in growth, further achondroplasia tests which include amniocentesis, may be performed.