Introduction
Kniest dysplasia is a rare genetic disorder that affects the development of bones and cartilage in the body. This condition is characterized by short stature, a round face, and a compressed chest. People with Kniest dysplasia may also experience hearing and vision problems, joint pain, and difficulty breathing. Despite its rarity, Kniest dysplasia is a fascinating condition that has captured the attention of medical professionals and researchers around the world.
What Is Kniest Dysplasia?
Kniest dysplasia is a rare genetic disorder that affects how human bodies grow and develop. It results from changes or mutations in a particular gene that instructs the body how to produce the protein collagen, which is necessary for the formation of bones and cartilage. People with Kniest dysplasia typically have short stature, meaning they are shorter than most people their age. In simpler terms, it leads to dwarfism (short stature) and other deformities that can affect the quality of life of the affected individual.
What Is the Cause of Kniest Dysplasia?
Kniest dysplasia is caused by mutations in the COL2A1 gene, which provides instructions for making type II collagen. Type II collagen is an essential protein for building bones and cartilage throughout the body. Mutations in this gene disrupt the structure and function of type II collagen, which leads to the abnormal bone and cartilage development characteristic of Kniest dysplasia.
Kniest dysplasia is passed down through generations in an autosomal dominant manner. This indicates that in order for a person to develop the disorder, they only need to inherit one copy of the mutated gene from either of their parents. In some cases, however, the condition may occur as a new mutation with no family history of the disorder.
Interestingly, mutations in the COL2A1 gene have also been associated with other skeletal dysplasias, including spondyloepiphyseal dysplasia congenita (SEDC, a genetic disorder that affects bones), Stickler syndrome (a connective tissue disorder that affects eyes) and achondrogenesis type II (a skeletal disorder). These conditions share some similar features with Kniest dysplasia, such as short stature and skeletal abnormalities, but have distinct differences as well.
What Are the Symptoms of Kniest Dysplasia?
The symptoms of Kniest dysplasia can vary widely, even among individuals with the same genetic mutation. However, some common features of Kniest dysplasia include the following:
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Short Stature: Children with Kniest dysplasia are usually shorter than their peers due to a shortened trunk and shortened limbs. The average height of an adult suffering from this rare disease ranges from 42 to 58 inches.
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Facial Abnormalities: Children with Kniest dysplasia may have a flat facial profile, a small chin, and a prominent forehead.
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Joint Problems: Children with Kniest dysplasia may have joint pain and stiffness due to abnormal cartilage growth. It can also cause arthritis. This can also lead to joint instability, which increases the risk of dislocations.
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Vision and Hearing Problems: Some children with Kniest dysplasia may face vision and hearing problems due to abnormalities in the structure of the eyes and ears.
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Breathing Difficulties: In severe cases, the chest and airway may be affected, leading to respiratory problems.
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Foot Deformities: Some children with Kniest dysplasia may have foot deformities, such as clubfoot, which can affect mobility and cause pain.
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Cleft Palate: Kniest dysplasia can cause a cleft palate, a condition in which the roof of the mouth (palate) does not fully develop.
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Progressive Abnormal Curvature of the Spine: Kniest dysplasia can lead to kyphoscoliosis, a progressive abnormal curvature of the spine that can cause back pain, difficulty breathing, and other complications.
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Flattened Vertebrae: Kniest dysplasia can cause flattened vertebrae, known as platyspondyly, which can also contribute to spinal deformities.
It is important to remember that Kniest dysplasia is a rare disease, and some people may have milder symptoms and be able to live relatively normal lives.
How Is Kniest Dysplasia Diagnosed?
Sometimes, Kniest dysplasia can be detected before a baby is born if a special test called a prenatal ultrasound shows that the baby's arms and legs are shorter than expected. To confirm the diagnosis, doctors can use genetic testing by collecting a sample of amniotic fluid through a procedure called amniocentesis. Genetic testing can confirm a diagnosis of Kniest dysplasia by identifying mutations in the COL2A1 gene.
If there is a history of Kniest dysplasia in the family and the specific gene change is known, doctors can also use a test called chorionic villus sampling (CVS) to check the baby for the same gene change while the baby is still in the womb.
Kniest dysplasia can also be diagnosed after the baby is born by looking at their growth (age milestones), and physical features, and taking X-rays. Doctors can also perform genetic testing to confirm the diagnosis.
In addition, doctors may also use imaging tests, such as X-rays, CT (computed tomography) scans, or MRI (magnetic resonance imaging) scans, to get a closer look at the bones and joints. These tests can reveal specific abnormalities that are associated with Kniest dysplasia, such as flattened vertebrae or abnormalities of the long bones in the arms and legs.
It is important to note that Kniest dysplasia is a rare disorder, and it can be difficult to diagnose. Some people with mild forms of the disorder may go undiagnosed for many years, while others may be misdiagnosed with other types of skeletal dysplasia.
What Is the Life Expectancy of Kniest Dysplasia?
The life expectancy for individuals with Kniest dysplasia can vary depending on the severity of the condition and the individual's overall health. In general, however, individuals with Kniest dysplasia have a normal lifespan and can live into adulthood.
It is important to note that Kniest dysplasia can cause a range of health problems, including breathing difficulties, spinal cord compression, and hearing loss. These complications can affect an individual's quality of life and may require medical intervention to manage.
With proper medical care and management of associated health problems, individuals with Kniest dysplasia can live a long and fulfilling life. It is important for individuals with Kniest dysplasia and their families to work closely with their healthcare team to ensure they receive the necessary support and care to manage the condition and any associated health issues.
What is the Treatment for Kniest Dysplasia?
People with Kniest dysplasia require care from a team of specialized healthcare professionals who have expertise in different areas of the body. This team may include an orthopedic surgeon for bone and joint problems, a neurologist or neurosurgeon for spinal cord issues, a genetics doctor to help families understand the genetic changes and plan for future medical care, an ophthalmologist for eye problems, an ear, nose, and throat doctor for hearing problems, a pulmonologist for breathing problems, a pediatrician for routine care, a physical therapist for muscle strength and joint motion, and an occupational therapist for help with everyday activities like writing and eating.
How Should Parents Care for Their Child Having Kniest Dysplasia?
Here are some important ways in which parents can support their children with Kniest dysplasia
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Treat the child according to their age, not their size, and encourage others to do the same.
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Talk about Kniest dysplasia positively and encourage their self-esteem.
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Adapt the environment to suit their needs, like using a light switch extender and a stepstool.
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Answer questions about Kniest dysplasia simply and highlight their unique qualities.
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Always give them emotional support.
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Encourage the child to try different activities, but check with a doctor before participating in sports.
Conclusion
To sum up, Kniest dysplasia can affect the physical and emotional health of the affected individual. Because it is a rare disease, not many people get it. But if it occurs, good family support, good treatment, and a good surrounding environment can help the individual ease their life.
