Langer mesomelic dysplasia
|Langer mesomelic dysplasia|
|a)Schematic view SHOX protein b) cellular factors that interact with SHOX|
Langer mesomelic dysplasia (LMD) is a rare congenital disorder characterized by an altered bone formation that causes a severe short and disproportionate stature.
Signs and symptoms
Clinically and radiologically the disease is characterized by severe shortening of long bones (limb's both proximal and median segments are affected), aplasia or severe hypoplasia of ulna and fibula, thickened and curved radius and tibia. These anomalies can cause deformities of the hands and feet. Hypoplasia of the mandible can also be present.
At the core of the disorder there is a homozygous or compound heterozygous mutation or deletion of the SHOX (Short Stature Homeobox), SHOXY (Short Stature Homeobox Y-linked) or PAR1 (where SHOX enhancer elements are located) genes, which is inherited in a pseudosomal recessive manner.
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. May also be suspected by ultrasound during the second trimester of gestation.
It's part of the mesomelic and rhizomelic skeletal dysplasias, primary bone diseases in which the short stature is due to a lack of complete bone development of the limb's long bones. It's strictly related to another disease, the Léri–Weill dyschondrosteosis, of which it seems to be the homozygothic variant, clinically more severe (it differs from this disorder for the absence, in some cases, of the Madelung deformity too).
There is no known cure. In selected patients orthopaedic surgery may be helpful to try to gain some functionality of severely impaired joints.
Life expectancy is normal.
- ↑ "Langer mesomelic dysplasia | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Archived from the original on 20 April 2021. Retrieved 20 December 2021.