Metatrophic dwarfism is characterized by abnormal skeletal development. Infants typically present with a long trunk with disproportionately short extremities. Length is usually normal. The chest may be narrow and a tail-like appendage may be present at the level of the coccyx (tailbone). The joints are prominent with decreased mobility. The fingers and toes are long. The proportions change during childhood with relative shortening of the trunk due to progressive kyphosis and relatively long extremities. Chest deformity and flexion contractures of major joints is common. Hyperextensibility of the fingers may also be present. Intellectual development is usually normal.[3]
Radiologic features include severe platyspondyly (flattened bones of the spine), severe metaphyseal enlargement, and shortening of the long bones.[2]
The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
| Signs and Symptoms | Approximate number of patients (when available) |
| Abnormal cortical bone morphology | Very frequent (present in 80%-99% of cases) |
| Abnormal enchondral ossification | Very frequent (present in 80%-99% of cases) |
| Abnormal form of the vertebral bodies | Very frequent (present in 80%-99% of cases) |
| Abnormality of the intervertebral disk | Very frequent (present in 80%-99% of cases) |
| Abnormality of the metaphyses | Very frequent (present in 80%-99% of cases) |
| Abnormality of the ribs | Very frequent (present in 80%-99% of cases) |
| Halberd-shaped pelvis | Very frequent (present in 80%-99% of cases) |
| High forehead | Very frequent (present in 80%-99% of cases) |
| Hypoplastic cervical vertebrae | Very frequent (present in 80%-99% of cases) |
| Joint stiffness | Very frequent (present in 80%-99% of cases) |
| Kyphosis | Very frequent (present in 80%-99% of cases) |
| Long thorax | Very frequent (present in 80%-99% of cases) |
| Micromelia | Very frequent (present in 80%-99% of cases) |
| Narrow chest | Very frequent (present in 80%-99% of cases) |
| Rough bone trabeculation | Very frequent (present in 80%-99% of cases) |
| Scoliosis | Very frequent (present in 80%-99% of cases) |
| Severe short stature | Very frequent (present in 80%-99% of cases) |
| Skeletal dysplasia | Very frequent (present in 80%-99% of cases) |
| Aplasia/Hypoplasia of the lungs | Occasional (present in 5%-29% of cases) |
| Camptodactyly of finger | Occasional (present in 5%-29% of cases) |
| Cataract | Occasional (present in 5%-29% of cases) |
| Cleft palate | Occasional (present in 5%-29% of cases) |
| Clinodactyly of the 5th finger | Occasional (present in 5%-29% of cases) |
| Fetal akinesia sequence | Occasional (present in 5%-29% of cases) |
| Flexion contracture | Occasional (present in 5%-29% of cases) |
| Hydrocephalus | Occasional (present in 5%-29% of cases) |
| Low-set, posteriorly rotated ears | Occasional (present in 5%-29% of cases) |
| Peripheral axonal neuropathy | Occasional (present in 5%-29% of cases) |
| Abnormal metaphyseal vascular invasion | - |
| Absent primary metaphyseal spongiosa | - |
| Anisospondyly | - |
| Autosomal dominant inheritance | - |
| Brachydactyly syndrome | - |
| Caudal appendage | - |
| Dumbbell-shaped metaphyses | - |
| Epiphyseal dysplasia | - |
| Flared femoral metaphysis | - |
| Flared humeral metaphysis | - |
| Hyperplasia of the femoral trochanters | - |
| Long coccyx | - |
| Platyspondyly | - |
| Relatively short spine | - |
| Respiratory failure | - |
| Short finger | - |
Recent evidence suggests that metatropic dwarfism is caused by mutations in the TRPV4 gene on chromosome 12q24.1.[2] Inheritance may be autosomal recessive or autosomal dominant.[2][3]
Individuals affected by metatropic dwarfism may benefit from genetic counseling. Information about how to locate a genetics professional can be found within the Services section on the resources page.
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
Treatment of metatropic dwarfism is symptomatic and supportive. Physiotherapy and occupational therapy can help with prevention of progressive joint disease. Bracing may be used for kyphosis with adjustment and/or replacement as the child grows. This type of treatment should be maintained until skeletal maturity is reached or until spinal fusion is feasible. Spinal fusion is used to prevent damage to the cervical part of the spinal cord.[3]
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
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I was diagnosed with a rare disease as a child. Recently, at age 21, I learned that I have metatropic dwarfism. My doctors haven't been able to give me much information. Can you tell me more about this condition, including treatment options? See answer
