Opsismodysplasia

Presentation

Opsismodysplasia can be characterized by a delay in bone maturation, which refers to "bone aging", an expected sequence of developmental changes in the skeleton corresponding to the chronological age of a person. Factors such as gender and ethnicity also play a role in bone age assessment. The only indicator of physical development that can be applied from birth through mature adulthood is bone age. Specifically, the age and maturity of bone can be determined by its state of ossification, the age-related process whereby certain cartilaginous and soft tissue structures are transformed into bone. The condition of epiphyseal plates (growth plates) at the ends of the long bones (which includes those of the arms, hands, legs and feet) is another measurement of bone age. The evaluation of both ossification and the state of growth plates in children is often reached through radiography (X-rays) of the carpals (bones of the hand and wrist). In opsismodysplasia, the process of ossification in long bones can be disrupted by a failure of ossification centers (a center of organization in long bones, where cartilage cells designated to await and undergo ossification gather and align in rows) to form. This was observed in a 16-month-old boy with the disorder, who had no apparent ossification centers in the carpals (bones of the hand and wrist) or tarsals (bones of the foot). This was associated with an absence of ossification in these bones, as well as disfigurement of the hands and feet at age two. The boy also had no ossification occurring in the lower femur (thigh bone) and upper tibia (the shin bone).

Genetics

Opsismodysplasia is inherited in an autosomal recessive manner. This means the defective gene(s) responsible for the disorder is located on an autosome, and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder. Currently, no specific mutation in any gene has been found to cause the disorder.

It appears that the gene inositol polyphosphate phosphatase-like 1 is the cause of this condition in at least some cases.

Epidemiology

Opsismodysplasia is a very rare disorder, and is estimated to occur in less than 1 in 1,000,000 people.

History

The disorder was first described by Jonathan Zonana and associates in 1977. and Maroteaux was the first to call the disorder "opsismodysplasia", in a 1984 journal report of three affected individuals. The name derives from the Greek opsismos, meaning "late", while the term dysplasia refers to development.

References

References

1. "OMIM Entry - # 258480 - OPSISMODYSPLASIA; OPSMD".
2. (1977). "A unique chondrodysplasia secondary to a defect in chondroosseous transformation". Birth Defects Original Article Series.
3. (Sep 1984). "Opsismodysplasia: A new type of chondrodysplasia with predominant involvement of the bones of the hand and the vertebrae". American Journal of Medical Genetics.
4. (Mar 2003). "Clinical, radiological, and chondro-osseous findings in opsismodysplasia: Survey of a series of 12 unreported cases". Journal of Medical Genetics.
5. (Mar 1999). "Five familial cases of opsismodysplasia substantiate the hypothesis of autosomal recessive inheritance". American Journal of Medical Genetics.
6. "::Opsismodysplasia". Orphanet.
7. (1991). "Approach to skeletal maturation". Hand Clinics.
8. (1996). "The assessment of skeletal maturation". Hormone Research.
9. (1997). "The biology of bone maturation and ageing". Acta Paediatrica. Supplement.
10. (Jun–Jul 2007). "Automatic bone age assessment for young children from newborn to 7-year-old using carpal bones". Computerized Medical Imaging and Graphics.
11. (Jun–Jul 2007). "Bone age assessment of children using a digital hand atlas". Computerized Medical Imaging and Graphics.
12. (1910). "Anatomy, descriptive and applied". Lea & Febiger.
13. (Feb 1994). "Additional case of opsismodysplasia supporting autosomal recessive inheritance". American Journal of Medical Genetics.
14. Chai EC, Singaraja RR (2013) Opsismodysplasia: Implications of mutations in the developmental gene INPPL1. Clin Genet doi: 10.1111/cge.12136
15. (1982). "Four recently described osteochondrodysplasias". Progress in Clinical and Biological Research.