The diagnostic dilemmas of skeletal dysplasia:classification, frequency and mode of inheritance of different type (a clinical and radiological overview)
11 till 15 October 2012، Tehran - Iran
Presentation Type: Speech
There are more than 5000 known congenital malformation syndromes so far identified, about 400 involve skeleton, including 200 different type of skeletal dysplasia’s. Usually skeletal dysplasia are a primary result of mutation genes that are expressed in chondro-osteus tissue, however there are also some other secondary dysplasia caused by abnormalities of extra-osteus factors with effects on the skeletal system as by metabolic errors as by hypophosphatemic rickets. The classification of skeletal dysplasia is principally based on radiological features of skeletal changes. Thanks to progress in molecular genetics especially in the last decade distinctions at the DNA level permit refinements in classification resulting in an increasing number of subtype of dysplasia. Some dysplasia with similar morphological findings with or without the same inheritance as well as their rare incidence are all reasons for diagnostic dilemma in this field. The first step in diagnosis of skeletal dysplasia is the responsibility of the pediatricians to observe a disproportionate skeletal development, unusual habitués with or without mental retardat ion as well as other clinical signs.The second step is more difficult and includes: Genetic counseling and interpretation of skeletal changes by radiological findings in affected patients and their families.The rare incidence of skeletal dysplasia on one hand and it’s diversities in morphology on other hand require some experience and therefore is recommended to be centralized. In this manner genetic clinicians and radiologists gain the ability and expertise in this field. Such a centralization exists in the Netherlands for many years as a study group (club) for skeletal dysplasia. As a member of this study group I would like to give an overview of lethal and non-lethal types of skeletal dysplasia and their genetic transmission.The importance of radiological approach and the specific findings of skeletal dysplasia will be demonstrated within scope of this meeting probably in 2 sessions. From each of the 22 categories classified by Lachman one or two cases will be shown including clinical findings, inheritance and characteristical radiological findings.