What causes achondroplasia?

Answer 1

Achondroplasia is inherited by an autosomal dominant gene that causes abnormal cartilage formation. Autosomal dominant inheritance means that the gene is located on one of the autosomes (chromosome pairs 1 through 22). This means that males and females are equally affected. Dominant means that only one gene is necessary to have the trait. When a parent has a dominant trait, there is a 50 percent chance that any child they have will also inherit the trait. So, in some cases, the child inherits the achondroplasia from a parent with achondroplasia. The majority of achondroplasia cases (80 percent), however, are the result of a new mutation in the family - the parents are of average height and do not have the abnormal gene.

As mentioned, persons with achondroplasia have a 50 percent chance to pass the gene to a child, resulting in the condition. If both parents have achondroplasia, with each pregnancy, there is a 50 percent chance to have a child with achondroplasia, a 25 percent chance that the child will not inherit the gene and be of average height, and a 25 percent chance that the child will inherit one abnormal gene from each parent, which can lead to severe skeletal problems that often result in early death.

Geneticists have found that fathers who are older than 45 have a higher chance of having children with certain autosomal dominant conditions such as achondroplasia, but no cause for the new mutations in sperm has been discovered at this time.

The gene responsible for achondroplasia was discovered in 1994 making accurate prenatal diagnosis available, in most cases.

Answer 2

Achondroplasia is inherited by an autosomal dominant gene that causes abnormal cartilage formation. Autosomal dominant inheritance means that the gene is located on one of the autosomes (chromosome pairs 1 through 22). This means that males and females are equally affected. Dominant means that only one gene is necessary to have the trait. When a parent has a dominant trait, there is a 50 percent chance that any child they have will also inherit the trait. So, in some cases, the child inherits the achondroplasia from a parent with achondroplasia. The majority of achondroplasia cases (80 percent), however, are the result of a new mutation in the family - the parents are of average height and do not have the abnormal gene.

Answer 3

a) The condition is caused by a new mutation in the fibroblast growth factor receptor 3 (FGFR3) gene. This gene is believed to be responsible for achondroplasia dwarfism; however, scientists do not know why this mutation occurs. c)Characteristic symptoms of achondroplasia dwarfism include: * An average-size trunk. * Short arms and legs, with particularly short upper arms and thighs. * An enlarged head (macrocephaly) with a prominent forehead. * Fingers that are typically short. The ring finger and middle finger may diverge, giving the hand a three-pronged (trident) appearance. d) Achondroplasia dwarfism can also be inherited in an autosomal dominant pattern, which means that one copy of the altered gene in each cell is sufficient to cause the disorder. In these cases, one of the parents with achondroplasia dwarfism passes on the FGFR3 gene to the child. f, g )Although there are no achondroplasia treatments that will cure achondroplasia, there are treatments that involve preventing or treating the signs, symptoms or health conditions that occur as a result of achondroplasia. Achondroplasia treatments also focus on social and family support.

Answer 4

Please see the webpages for more details on Achondroplasia.