Multiple Synostosis Syndromes
Multiple Synostosis Syndromes are skeletal disorders in which inappropriate fusions across joints have occurred. At least two forms of this condition have been described. One form, SYNS1, is an autosomal dominant condition. It typically affects finger joints, large joints (such as the hip), and the joints of the spinal column. Hearing loss can occur if the small bones of the middle ear become fused. This can be surgically treated. The second form, SYNS2, is also autosomal dominant. It typically affects finger, wrist, and elbow joints. The spine and hearing are generally not involved. While these joint fusions may not be evident at birth, they become problematic in childhood. The majority of affected people are of normal intelligence.
The gene responsible for the SYNS1 form of multiple synostosis syndrome is called NOG. It maps to human chromosome 17q22. NOG encodes a secreted protein, called NOGGIN, that inhibits a class of growth factors. A related disorder, proximal symphalangism (SYM1), is caused by a different change in the NOG gene. We are currently performing mutation detection on the NOG gene on a research basis. To the best of our knowledge, molecular testing to make the diagnosis or to identify unaffected carriers is not clinically available. Physicians seeking assistance in making this diagnosis are welcome to contact us. Additional resources that may be of value are listed below.
We are currently seeking additional individuals and families with SYNS1 to participate in our research. We would like to identify additional disease causing genetic changes and correlate them with the specific pattern of joint involvement seen in the corresponding patient. These genotype/phenotype correlations will enable us to better understand how joints form. Blood samples with accompanying X-rays and clinical information from additional patients would be greatly appreciated.
The gene responsible for the SYNS2 form of multiple synostosis syndrome has been mapped to human chromosome 20. Less is known about this gene. The participation of additional families in this research would aid in the search for the gene. Blood samples with accompanying X-rays and clinical information from additional patients would be greatly appreciated. Adding understanding and finding the responsible gene for SYNS2 are necessary steps to opening new diagnostic and therapeutic avenues.
If you are a patient, or have a patient with one of the multiple synostosis syndromes interested in participating in our research, please contact us. For sample submission instructions, click on How to submit samples". Have the participant sign our consent form.
If you are a patient or family member interested in communicating with other families, please email Dr. Warman Whenever new consenting family members contact us, emails (or phone numbers) will be exchanged. The Center for the Study of Genetic Bone and Joint Disorders does not monitor communications directly between families, and therefore cannot be responsible for the accuracy of information exchanged.
Additional information can be obtained through Online Mendelian Inheritance in Man, a database catalogue of human genes and genetic disorders edited by Victor A. McKusick and colleagues.The OMIM number for SYNS1 is 186500.
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