Metaphyseal chondrodysplasia Schmid type
Definition[edit | edit source]
Metaphyseal chondrodysplasia, Schmid type (MCDS) is a type of skeletal disorder in which there is abnormal bone formation at the end of the long bones (metaphyses).
cause[edit | edit source]
MCDS is caused by a mutation in one of the collagen genes known as COL10A1.
Inheritance[edit | edit source]
The mutation may be inherited from a parent or may happen for the first time in an affected individual.The MCDS mutation is passed on in an autosomal dominant manner.
Signs and symptoms[edit | edit source]
- Symptoms include short stature with abnormally short arms and legs (short-limbed dwarfism) and bowed legs (genu varum).
- Additional signs and symptoms may include lumbar lordosis, leg pain, joint pain, hip deformities, and an outward flaring of the bones of the lower rib cage. As a result of the hip and leg findings, individuals with this condition may have an unusual walk that resembles a waddle.
Clinical presentation[edit | edit source]
For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.
80%-99% of people have these symptoms
- Coxa vara
- Distal femoral metaphyseal abnormality(Abnormality of wide portion of outermost thighbone)
- Limb undergrowth(limb shortening)
- Thick growth plates
- Waddling gait('Waddling' gait)
30%-79% of people have these symptoms
- Abnormalities of the metaphyses of the hand(Abnormality of the wide portion of the hand bone)
- Anterior rib cupping
- Broad proximal phalanges of the hand(Broad innermost finger bones of the hand)
- Disproportionate short-limb short stature(Short limb dwarfism, disproportionate)
- Distal femoral metaphyseal irregularity
- Femoral bowing(Bowed thighbone)
- Flared metaphysis(Flared wide portion of long bone)
- Genu varum(Outward bow-leggedness)
- Hip dysplasia
- Metaphyseal cupping of metacarpals(Cupping of wide portion of long bone of hand)
- Metaphyseal cupping of proximal phalanges
- Osteosclerosis of ribs(Increased bone density in ribs)
- Proximal femoral metaphyseal irregularity
- Short tubular bones of the hand
- Widened proximal tibial metaphyses(Wide innermost wide portion of shankbone bone)
5%-29% of people have these symptoms
- Arthralgia(Joint pain)
- Irregular vertebral endplates
- Lumbar hyperlordosis(Excessive inward curvature of lower spine)
- Obesity(Having too much body fat)
- Platyspondyly(Flattened vertebrae)
- Radial metaphyseal irregularity
- Ulnar metaphyseal irregularity
Diagnosis[edit | edit source]
- No formal diagnostic criteria for Schmid metaphyseal chondrodysplasia (SMCD) have been established. The diagnosis should be suspected in individuals with the following clinical, laboratory, and radiographic findings.[1][1].
Clinical findings
- Short-limbed short stature by age two years (in >60%)
- Genu varum (bowed legs) (>60%)
- Waddling gait (>80%)
- Lumbar lordosis by age three to five years
- Normal craniofacies and absence of extraskeletal manifestations
Laboratory findings. Normal serum calcium, phosphate, vitamin D, and alkaline phosphatase
Radiographic findings
- Shortening of the tubular bones (>60%)
- Metaphyseal irregularities of the long bones (e.g., splaying, flaring, cupping) especially the proximal and distal femora (~100%)
- Widening of the growth plates
- Coxa vara (>80%)
- Anterior cupping, sclerosis, and splaying of the ribs (>90%)
- Mild hand involvement including shortening of the tubular bones and metaphyseal cupping of the metacarpals and proximal phalanges (~50%).
- Radiographic phalangeal and metacarpal findings may resolve with age.
The diagnosis of SMCD is established in a proband with characteristic clinical and radiographic features and/or a heterozygous pathogenic variant in COL10A1 identified by molecular genetic testing.
Treatment[edit | edit source]
- Management of orthopedic complications by orthopedist, physiotherapist, occupational therapist, and pain specialist as indicated.
- Joint-friendly exercise, weight management
- Mobility device as needed
- Corrective osteotomy by guided growth surgery or valgus osteotomy may be considered in late childhood / adolescence in those with progressive or symptomatic varus deformity, significant coxa vara, triangular fragment in the interior femoral neck, or poor or deteriorating function
- Exercise and support from nutritionist to maintain healthy weight
- Psychosocial support
- Environmental or occupational modifications as needed for short stature with recommendations from occupational therapy as needed.[2][2].
References[edit | edit source]
- ↑ Richmond CM, Savarirayan R. Schmid Metaphyseal Chondrodysplasia. 2019 Oct 21. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2021. Available from: https://www.ncbi.nlm.nih.gov/books/NBK547823/
- ↑ Richmond CM, Savarirayan R. Schmid Metaphyseal Chondrodysplasia. 2019 Oct 21. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2021. Available from: https://www.ncbi.nlm.nih.gov/books/NBK547823/
External links[edit | edit source]
Classification | |
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External resources |
NIH genetic and rare disease info[edit source]
Metaphyseal chondrodysplasia Schmid type is a rare disease.
Metaphyseal chondrodysplasia Schmid type Resources | ||
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