Achondrogenesis is a genetic disorder that results in skeletal abnormalities such as small limbs, short trunk and a narrow chest. It occurs when a person’s body does not produce enough growth hormone.
Achondrogenesis affects cartilage and bone development. As a result of serious health problems, infants with achondrogenesis usually die before birth, are stillborn, or die soon after birth from respiratory failure. Some infants have lived for a short time with intensive medical support.
The baby with achondrogenesis type 1A has a very soft skull bone and his/her limbs are short. The baby’s chest is narrow, owing to which it hard for the baby to breathe. The bones in the spine and pelvis do not develop well. Moreover, the baby also has short ribs that break easily. Based on a few infants with achondrogenesis type 1A, researchers believe that this form of the disorder is inherited in an autosomal recessive pattern.
Achondrogenesis type 1B is similar to achondrogenesis type 1A, and can be differentiated on a genetic test. In addition to achondrogenesis type 1A characteristics, the baby has round belly and sometimes a pouch near the groin or belly button. Besides, his or her feet may be inwardly rotated and toes are also very short.
Achondrogenesis type 1B also has an autosomal recessive pattern of inheritance. Autosomal recessive inheritance means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.
Babies born with type 2 achondrogenesis have short limbs, a narrow chest, short ribs and their lungs are not well developed. The roof of their mouth may have an opening (cleft palate) besides a small chin and large forehead. Some infants with the disorder have too much fluid in their bodies before they are born.
Achondrogenesis type 2 is considered an autosomal dominant disorder because one copy of the altered gene in each cell is sufficient to cause the condition. It is almost always caused by new mutations in the COL2A1 gene and typically occurs in people with no history of the disorder in their family.
Determining whether a condition in a family is inherited is not easy. If you think the disorder runs in your family, consult a genetic professional who will study a person’s family history to figure out the genetic association. They will enquire about the health of people from several generations of the family, usually first-, second-, and third-degree relatives.
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