By Nick Albano and Leo Cavedagne
Dwarfism:
About Dwarfism: The most common type of dwarfism is called Achondroplasia. In Achondroplasia the problem is not in forming cartilage but in converting it to bone (a process called ossification), particularly in the long bones of the arms and legs. Achondroplasia is similar to another skeletal disorder called Hypochondroplasia, but the features of Achondroplasia tend to be more severe.
Description of the inheritance pattern: Achondroplasia is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. About 80 percent of people with achondroplasia have average-size parents; these cases result from new mutations in the FGFR3 gene. People that have achondroplasia have inherited an altered FGFR3 gene from one or two affected parents. Individuals who inherit two altered copies of this gene will have a severe form of achondroplasia. These individuals are usually stillborn or die shortly after birth from respiratory failure.
About the Gene:
- What does the gene normally do on a molecular/cellular/tissue level: Mutations in the FGFR3 gene cause achondroplasia. The FGFR3 gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. This gene is normally involved in just the tissue level.
- What the abnormal gene does or does not do: The result of the abnormal gene is that Two specific mutations in the FGFR3 gene are responsible for almost all cases of achondroplasia. Researchers believe that these mutations cause the FGFR3 protein to be overly active. Because of this, it interferes with skeletal development and leads to the disturbances in bone growth seen with this disorder.
- Where the gene is located: The FGFR3 gene located at 4p16.3 is translocated to chromosome 14q32 as a result of a novel and karyotypically undetectable t(4;14)(p16.3;q32) chromosomal translocation in multiple myeloma (MM), a malignant proliferation of plasma. cells.
Phenotypic expression (symptoms for Achondroplasia) may include:
- - A large head with a prominent forehead
- A flattened bridge of the nose
- Protruding jaw
- Crowded and misaligned teeth
- Forward curvature of the lower spine
- Bowed legs
- Flat, short, broad feet
- Double- jointedness
Possible treatments: People with Dwarfism related to growth hormone deficiency can be treated with a growth hormone. Other treatments may include
- insertion of a shunt to drain excess fluid and relieve pressure on the brain
- A tracheotomy to improve breathing through small airways.
- Corrective surgeries for deformities such as cleft palate club foot, or bowed legs.
- Surgery to remove tonsils or adenoids to improve breathing problems related to large tonsils, small facial structures, and/or a small chest.
- Surgery to widen the spinal canal (the opening through which the spinal cord passes) to relieve spinal cord compression
- Physical therapy to strengthen muscles and increase joint range of motion.
- Back braces to improve curvature of the spine.
- Placement of draining tubes in the middle ear to help prevent hearing loss due to repeated ear infections.
- Orthodontic treatment to relieve crowding of teeth caused by a small jaw.
- Nutritional guidance and exercise to help prevent obesity which can aggravate skeletal problems.
Prevalence of the disorder: Achondroplasia is the most common type of short-limbed dwarfism. The condition occurs in 1 in 15,000 to 40,000 newborns. As long as you get the defective gene, the prevalence of this disease will be common anywhere.
Informational Video on Dwarfism: