HomeHealth articlesachondrogenesisAchondrogenesis | Types | Causes | Diagnosis | Treatment

Achondrogenesis - Types, Causes, Diagnosis and Treatment

Verified dataVerified data
0

4 min read

Share

Infants with achondrogenesis either are stillborn or die immediately after birth, as it is a fatal disorder. The health problems associated with it are life-threatening. The article below will guide you in detail.

Medically reviewed by

Dr. Keerthi

Published At March 25, 2022
Reviewed AtApril 18, 2023

What Is Achondrogenesis?

Achondrogenesis refers to the group of severe disorders that affect the cartilage and the development of bone. The term was first given by Italian pathologist Marco Fraccaro. This term is derived from a Greek word meaning "not producing cartilage." Children with this disorder have a small body, short limbs, and other skeletal abnormalities.

Achondrogenesis is a serious health problem. Infants with achondrogenesis typically die before birth or die soon after birth from respiratory failure; however, some infants have survived for a short duration of time with the right intensive medical support. It is otherwise known as achondrogenesis syndrome.

What Are the Different Types of Achondrogenesis?

Achondrogenesis is classified into three different types. Their characteristics, inheritance pattern, and genetic causes differ accordingly. Here are the types of achondrogenesis:

  • Type 1A.

  • Type 1B.

  • Type 2.

Type 1A:

Type 1A is the least understood among the three forms of achondrogenesis. Achondrogenesis type 1A is otherwise known as the Houston-Harris type. The infants affected with this type have the following characteristics:

  • Extremely short limbs.

  • Narrow chest.

  • Short ribs that can fracture easily.

  • Lack of bone formation in the skull, spine, and pelvis.

Type 1B:

Type 1B is otherwise known as the Parenti-Fraccaro type. This type shows the following features:

  • Extremely short limbs.

  • Narrow chest.

Type 1A and type 1B are hard to diagnose without genetic testing.

Type 2:

Achondrogenesis type 2 is otherwise known as the Langer-Saldino type. Infants affected by this type 2 have the following features:

  • Short arms and legs.

  • Narrow chest with short ribs.

  • Underdeveloped lungs.

  • Lack of bone development in the spine and pelvis.

  • Prominent forehead.

  • Small chin.

  • Cleft palate.

The affected infants often have a condition known as hydrops fetalis, in which excess fluid builds up in the body before birth, and their abdomen is enlarged.

What Are the Causes for Achondrogenesis?

Typically achondrogenesis is a genetic condition. So parents can do nothing to cause it or to prevent it. Infants develop this condition due to abnormalities in the genes. Among the distinct types of achondrogenesis, type 1A and type 1B are autosomal recessive disorders. Infants develop this type when their parents copy an abnormal copy of a specific gene. A change (mutation) in the TRIP11 gene causes type 1A achondrogenesis, and a change in the SLC26A2 gene causes type 1B achondrogenesis.

Achondrogenesis is most often seen in parents who are closely related, as it is more likely that close relatives have the same genetic mutation.

In most cases, type 2 achondrogenesis is caused due to a de novo mutation and not something that is passed down from the parents. It is considered an autosomal dominant disorder as one copy of the mutated gene in each cell is sufficient. Mutation in the COL2A1 gene is responsible for causing type 2 achondrogenesis. Mutations in these particular genes cause the production of proteins that are not able to perform their functions properly within the body. Though it is clear that mutation in particular genes is the causative factor for achondrogenesis, scientists are not clear about what is causing these mutations (changes) and if anything can prevent them from occurring.

What Happens When Both the Parents Carry the Mutation in the Genes?

When both parents carry a mutation in the genes linked with achondrogenesis, then the child is likely to have:

  • 25 % probability of having achondrogenesis.

  • 50 % probability of carrying the mutation but not having the disorder.

  • 25 % chance of neither having the disorder nor carrying the mutated gene.

How Is Achondrogenesis Diagnosed?

Screening during pregnancy helps determine achondrogenesis. When diagnosed with this condition, genetic counseling is given to the parents to weigh the risks and benefits of pregnancy.

Ultrasound:

The ultrasound taken between the 12th and 14th week of pregnancy helps determine the condition. Achondrogenesis can resemble other conditions as well. To confirm the diagnosis, the doctor may recommend additional tests such as amniocentesis.

Genetic Testing:

Genetic testing is suggested for parents who have a higher chance of passing down the disorder, such as people with a family history of achondrogenesis or parents being closely related. Genetic testing can also help determine the type of achondrogenesis.

X-Ray:

After birth, it can be diagnosed when the infant has extremely short arms and legs, short ribs, short chest, and short trunk. X-ray findings help determine the underdeveloped skull, vertebrae, and rib cage.

Is Achondrogenesis a Common Condition?

Achondrogenesis is a rare condition. Among the different types of achondrogenesis, type 1A and type 1B are so rare that their prevalence has not been estimated yet. Type 2 achondrogenesis is seen in around 1 in 40,000 to 1 in 60,000 infants. If both parents carry the mutated gene, then around 1 in 4 infants have the chance of developing the disorder. Having family members affected with this disorder, then there is an increased likelihood of the child being a carrier.

Can Achondrogenesis Be Treated?

There is no cure found yet for achondrogenesis. With the results that come out from 12 weeks to 14 weeks screening, parents are guided with genetic counseling and about the risks of the condition. Some parents decide to terminate, whereas there are parents who are willing to continue their pregnancy. Most frequently, babies die before birth or soon after birth. So when the baby is born, treatment mainly focuses on alleviating the symptoms and giving support to both parents.

What Kind of Support Do Parents Require During Pregnancy or After Loss of the Baby?

The infants affected with achondrogenesis do not survive long after birth. So when the parents choose to terminate the pregnancy, they tend to experience painful emotions. They may have a fear of facing societal judgment and stigma. There are a lot of organizations to give mental support to the parents before or after the loss of the baby.

In instances when the infant dies in later pregnancy or immediately after birth, the woman is more likely to develop postpartum depression. Offering appropriate psychological and medical care to those women helps improve their well-being.

The parents who lost their child require maximum support from relatives and friends. It is good if relatives and friends could acknowledge the parents' decision as reasonable and right. Do not judge or insult the parents when they have decided to terminate the pregnancy. Give them moral and physical support.

What Is the Prognosis for Children Born With Achondrogenesis?

The affected infants usually die before birth or shortly after birth. When born with achondrogenesis, they may have underdeveloped lungs that may lead to serious breathing issues leading to lung failure. Eventually, they die.

Conclusion

There is no cure for achondrogenesis, so parents should be offered genetic counseling to weigh the risks and benefits of the subsequent pregnancies. Infant loss gives absolute distress, and parents should know that they are not alone. There are various organizations and social forums to help them with mental support for overall well-being.

Frequently Asked Questions

1.

How Many Newborns Are Affected by Achondrogenesis?

Achondrogenesis is a rare and severe genetic disorder that affects bone and cartilage development. The disease is more severe in infants, leading to death at or before birth due to lung failure. Nearly 1 in 40,000 to 60,000 newborns are affected with type 2 achondrogenesis. The chances are high if both the parents carry and pass on the defective gene (COL2A1) responsible for causing achondrogenesis. In such cases, 1 in 4000 infants is affected by achondrogenesis.

2.

Which Organelle Is Affected by Achondrogenesis?

Golgi apparatus is a cell organelle responsible for processing and transporting proteins. The genetic alterations in achondrogenesis affect the Golgi apparatus. It leads to the lack of protein transmission to the growth hormones. Therefore the growth of bone and cartilage is disturbed, leading to short limbs, a narrow chest, underdeveloped lungs, and a lack of bone development in the spine and pelvis.

3.

Is Achondrogenesis Life-Threatening?

Achondrogenesis is a severe condition characterized by shortening arms, legs, and various skeletal abnormalities. The classical features include premature birth, abnormal head shape, and fluid deposition in the body. It is a severe life-threatening disorder, and the infants usually do not survive after birth due to undeveloped or small lungs.

4.

Can Achondrogenesis Disease Be Inherited?

Achondrogenesis is an inherited disorder classified as type 1A, 1B, and 2. It is caused by genetic changes (mutations), namely:
- Type 1A- mutations in TRIP11 gene.
- Type 1B- mutations in SLC26A2 gene.
- Type 2- mutation in the COL2A1 gene.
- The mutations of the genes mentioned above lead to a deficiency of microtubules in the Golgi apparatus (cell organelle). It then leads to the lack of protein transfer essential for cartilage's proper development and functioning. The cartilage is a specialized tissue and is later converted to bone.

5.

How to Treat Achondrogenesis?

Achondrogenesis is a life-threatening disorder, and there is no treatment available to cure it. The life expectancy of the child is very less. Supportive and psychological care is essential for both the child and parents. It is prevented by avoiding inter-relation marriage, and genetic testing is done during pregnancy to detect the risk of such severe conditions and make decisions on it.

6.

What Happens if the Golgi Apparatus Malfunctions?

Golgi apparatus or Golgi body is a cell organelle responsible for processing and transporting proteins and lipids to target cells. Any malfunctioning of the Golgi apparatus leads to improper transport of proteins required for growth and development. As a result, it leads to several skeletal, neurological and connective tissue disorders.

7.

How Frequent Is Achondrogenesis?

Achondrogenesis is a rare disorder, and it affects males and females equally. Type 2 of achondrogenesis affects 1 in 40,000 to 1 in 60,000 newborns. The prevalence of type 1A and 1B is not known. There is a 25 % risk of acquiring the disease if both the mother and father carry the same defective gene. There is a 50 % chance of the infant carrying the defective gene and not possessing any symptoms.

8.

What Are the Characteristics of Achondrogenesis on Fetal Ultrasound?

The fetal ultrasound of achondrogenesis shows the following features:
- Short limbs.
- High abdomen.
- Narrow thorax.
- Poor mineralization of skull and spinal columns.
- Low-lying ears.
- Excessive accumulation of amniotic fluid (polyhydramnios).
- Pleural effusion (accumulation of fluid around the lungs).
Dr. Keerthi

Dr. Keerthi

Orthopedician and Traumatology

Tags:

achondrogenesis
Community Banner Mobile
By subscribing, I agree to iCliniq's Terms & Privacy Policy.

Source Article ArrowMost popular articles

Do you have a question on

achondrogenesis

Ask a doctor online

*guaranteed answer within 4 hours

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.

This website uses cookies to ensure you get the best experience on our website. iCliniq privacy policy