What is it?
Achondroplasia is a rare genetic disorder affecting an average of one in 25,000 people, caused by a mutation in the FGFR3 gene, located on chromosome 4, that leads to changes in the bone in the cartilage-forming zone, resulting in a disharmonious short stature. For this reason, it is classified as a skeletal dysplasia and is better known as achondroplastic dwarfism. Achondroplasia is not treatable, except for the possibility of surgical limb lengthening to achieve growth to enhance the quality of life.
Which are the symptoms?
Patients are characterized by short stature, shortened limbs in relation to the trunk, brachydactyly, macrocephaly, characteristic facial anomalies such as high forehead, prominent frontal cusps and sunken nasal root. Motor development can be delayed while cognitive development is not impaired. Adult height is 131±5.6 cm (males) and 124±5.9 cm (females).
- disharmonious short stature
- prominent forehead
How is it diagnosed?
The diagnosis is made in utero by chance on an ultrasound scan in the third trimester of pregnancy. In pregnancies when achondroplasia is suspected by ultrasound, the final diagnosis is made by fetal DNA testing with detection of the FGFR3 gene mutation. Preimplantation diagnosis is possible in specialized laboratories. After birth, clinical and radiographic evaluation reveals typical morphological changes, namely rhizomelia, generalized metaphyseal abnormalities, narrowing of the intervertebral distance of the lower lumbar vertebrae, abnormal pelvis with small square-shaped iliac wings, narrow sacroiliac incisura.
How is it treated?
Currently, there are no specific treatments except for the possibility of surgical limb lengthening to achieve growth that provides a better quality of life. This goal is achieved gradually through osteotomy operations and the use of external fixators, distraction and fixation devices placed outside the limb, which are then removed once bone consolidation is complete. Lengthening primarily affects the lower extremities and may involve the upper extremities at a later stage to limit the disproportion between the segments. The total number of operations is divided into 4 stages for the lower extremities and only 1 for the upper extremities. Each of these stages, which lengthens approximately 1/3 of the original length of the treated segment, takes an average of 8 to 12 months. This process involves a lengthy surgical and rehabilitative procedure that affects the life of the patient and his family, and is preferably performed at school age and is preceded by adequate cognitive, emotional and psychological preparation with dedicated staff.
- First stage of bilateral tibial lengthening
- First stage of bilateral femoral lengthening
- Second stage of bilateral tibia lengthening
- Second stage of bilateral femoral lengthening
- Possible stage of bilateral humerus lengthening
Where do we treat it?
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