Achondrogenesis

Once the disease causing mutations in achondrogenesis type 1A and IB have been identified in an affected family member the parents should be tested to confirm that they are carriers of the condition. Prenatal testing as well as preimplantation genetic diagnosis can be offered to the appropriate carrier. Referral to a genetic counselor is beneficial at this time to discuss the impact on the extended family.

Both Compassionate Friends and Helping After Neonatal Death Support Groups may be beneficial to parents.

Due to the fact that these conditions are lethal there are no specialists to see besides genetics to discuss family planning options and inheritance.

The TRIP11 gene provides instructions to create a protein that plays a roll in the Golgi apparatus formation which ensures the cell proteins work properly. Changes in the Golgi apparatus causes the cells to have problems converting cartilage to bone.
The SLC2A2 gene creates a protein that is essential in the development of cartilage and how it becomes bone. In Achondrogenesis type 1B the change in the SLC2A2 gene causes the structure of the cartilage to be abnormal and therefore it cannot be transformed into bone.

Achondrogenesis type 2 is caused by a change in the COL2A1 gene. This gene normally provides instructions for making a protein that creates type 2 collagen. This collagen is found mostly in cartilage. Changes in the COL2A1 gene causes the collagen not to form correctly and therefore disrupt the development of bone.

There is nothing that prevents achondrogenesis

This condition is most often referred to as achondrogenesis, however each subtype has additional names.

In achondrogenesis type 1B there are 4 mutations that have been seen in a number of affected individuals. Other variants seem to cause related disorders.

If a familial mutation(s) are known then other pregnancies can be tested for during the pregnancy.

There is not a usual abbreviation for achondrogenesis.

Achondrogenesis is a group of conditions that affect the cartilage and bone development. Individuals with achondrogenesis have a small body, short limbs, and other skeletal abnormalities.

The gene change for achondrogeneis type 1A is not well understood as of 5/20/2016 but in 2010 mutations in the TRIP11 gene was seen in 10 unrelated patients. Achondrogenesis type 1B is caused by a mutation in the SLC26A2 gene. Achondrogenesis type 2 is caused by mutations in the COL2A1 gene.

There are no forms of achondrogenesis that are not found to have a genetic change in one of these three genes.

There are no environmental or other outside influences that make the symptoms worse in achondrogenesis.

Achondrogenesis is usually a lethal condition. They infants are often stillborn or die shortly after birth from respiratory failure.

Achondrogenesis type 1A infants have extremely short limbs, a narrow chest, short ribs that fracture easily and a lack of normal bone development in the skull, spine and pelvis.
Achondrogenesis type 1B infants have extremely short limbs, narrow chest, and a prominent rounded abdomen. The fingers and the toes are short and there may be club feet. The often have an umbilical hernia and will sometimes have a hernia in the groin.
Achondrogeneis type 2 infants have short arms and legs, a narrow chest with short ribs and underdeveloped lungs. There is also a lack of normal bone development in the spine and pelvis. There are facial features that include a prominent forehead, a small chin and a cleft palate.

There is not routine newborn screening for achondrogenesis since most cases are diagnosed by ultrasound abnormalities during the pregnancy or at birth.

An individual with clinical features of achondrogenesis would benefit from a genetics consultation including molecular testing as well as a skeletal survey.

There are no clinical trials as of May 20, 2016 according to clinicaltrials.gov

There is no organ specific treatments/symptoms for achondrogenesis.

If your children are developing normal in utero and after birth then a diagnosis of achondrogenesis is not possible.

Due to the fact that the conditions are lethal the only management is palliative neonatal care.

Achondrogenesis types 1A and 1B are inherited in an autosomal recessive manner. Both parents are unaffected carriers of a genetic change and have a 1 in 4 or 25% chance of having an affected child. Achondrogenesis type 2 is inherited in an autosomal dominant manner and only one copy of the gene needs to be abnormal in order to be affected with the condition. Due to the lethality of achondrogenesis type 2 is it always a new mutation.

The patients with achondrogenesis often present in breech presentation and the pregnancy is complicated with polyhydramnios as well as the skeletal features in utero.

The short limbs and small chest can be seen as early as the anatomy scan routinely done at 20 weeks gestation. The small chest and short limbs may be identified earlier.

There is no specific place to donate money for research. Organizations such as Little People of America will be able to guide a family.

An individual with clinical features of achondrogenesis would benefit from a genetics consultation including molecular testing as well as a skeletal survey.

To find clinical research visit www.ClinicalTrials.gov.

As of May 20, 2016 there are no centers of excellence for achondrogenesis

The incidence of achondrogenesis type 1A and 1B is not known. The incidence of achondrogenesis type 2 is less than 1/40000 newborns.

Individuals with achondroplasia can have a normal life span and have limb abnormalities, but the size of the chest and ribs is not affected. It is also caused by mutations in a different gene.

Achondrogenesis is not likely if prenatal ultrasounds are normal.

Due to the severity of the condition and it being a lethal skeletal dysplasia, all have been found to be new mutations, or rarely gonadal mosaicism.

Your child may have a diagnosis of hypochondorgenesis, which is similar to achondrogenesis with different mutations in the same gene.

Achondrogenesis type 1A is also called Houston-Harris. Achondrogenesis type 1B is known as Parenti-Fraccaro. Achondrogenesis type 2 has been called Langer-Saldino type.

Carriers of a mutation in the SLC26A2 gene are not at an increased risk for a degenerative bone joint disease.