Langer mesomelic dysplasia
Langer Mesomelic Dysplasia (LMD) is a rare congenital disorder characterised by altered bone formation which typically causes affected individuals to experience shortening of the bones of the extremities, as well as an abnormally short stature.
| Langer mesomelic dysplasia | |
|---|---|
| Specialty | Medical genetics |
Signs and symptoms
The disease is characterized by severe shortening of long bones, affecting the limb's proximal and median segments. There is a severe underdevelopment or complete absence of the ulna and fibula (hypoplasia or aplasia), along with a thickened and curved radius and tibia. Additionally, these anomalies can lead to deformities of the hands and feet, and there may be hypoplasia of the mandible as well.
Pathogenesis
The disease is primarily caused by genetics, resulting from homozygous or compound heterozygous mutations or deletions of either the SHOX, SHOXY, or PAR1-gene. These genetic abnormalities are inherited in a pseudosomal recessive manner.
Diagnosis
Diagnosis may be suspected on the basis of the clinical and radiologic findings, and can supported by molecular analysis of the SHOX, SHOXY and PAR1 genes. The disease may also be suspected through ultrasound during the second trimester of gestation.
Classification
LMD is part of the mesomelic and rhizomelic skeletal dysplasias, which are primary bone diseases where the person's short stature is due to a lack of complete bone development of the limb's long bones. LMD is related to the disease Léri–Weill dyschondrosteosis.
Treatment
There is no known cure for LMD. In selected patients, orthopaedic surgery may be helpful to try to gain some functionality of severely impaired joints.
Prognosis
Life expectancy is normal.