Height, Ulnar Length and Forearm Function in Multiple Hereditary Exostoses

Study Overview
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Brief Summary
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the purpose of the present registry is to describe the epidemiology of forearm deformities in patients with Hereditary Multiple Exostoses and to identify, independent predictors of severity of the disease and potential association with genotypic patterns

Detailed Description
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Hereditary Multiple Exostoses (HME) is a rare pediatric autosomal dominant disorder caused by loss-of-function mutations in the genes encoding the heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. HME affects 1 in 50,000 people and has 100% penetrance but great variability in phenotypic expression. HME is characterized by formation of cartilaginous outgrowths, called osteochondromas or exostoses, next to the growth plates of many axial and appendicular skeletal elements, causing multiple, painful disfiguring and disabling skeletal deformities, and potential malignant transformation into peripherral chondrosarcoma. The involvement of upper-limb bones by HME is associated with greater loss of function than elsewhere in the body, but even here the loss of function may be limited. Moreover, the constant relationship between height and ulnar length has long been recognized in forensic medicine and has been recently analyzed also in HME, in order to predict the clinical and functional outcomes of the upper limb. the present registry aims to collect demographic, clinical, functional and radiographic information from patients with HME in order to establish phenotypic predictors of severity of the disease and potential association with genotypic patterns

Official Title
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Analysis of the Relationship Among Height, Ulnar Length and Forearm Function in Patients With Multiple Hereditary Exostoses and Association With the Genotypic Pattern

Conditions
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Exostoses, Multiple Hereditary

Intervention / Treatment
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* Diagnostic Test: blood and buccal swab genetic test
* Diagnostic Test: PUL
* Diagnostic Test: Range of motion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - patients with HME (> 2 exostoses) Exclusion Criteria: Patients with solitary exostoses Patients, adults or minors, who are unable to give their timely informed consent.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| HME group<br>204 children and adult patients with HME, admitted to our Hospital for diagnosis and treatment. the patients will be stratified by age in four subgroups: subgroup I (0-7 Years) subgroup II (8-12 Years) subgroup III (13-18 Years) subgroup IV (>18 Years) | Diagnostic Test: blood and buccal swab genetic test<br>* blood samples and buccal swabs will be obtained from patients with HME in order to analyze the genotype (EXT1 or EXT2 mutations) and correlate the genotypic pattern with the phenotypic presentation<br>Diagnostic Test: PUL<br>* measurement of ulnar length with anthropometer and patient's height<br>Diagnostic Test: Range of motion<br>* measurement of range of motion of elbow, forearm and wrist<br>|
| healty control group<br>204 children and adult voluntary healty controls will be stratified in the same manner and matched with the population in study in order to assess normal and pathologic growth. | Diagnostic Test: PUL<br>* measurement of ulnar length with anthropometer and patient's height<br>Diagnostic Test: Range of motion<br>* measurement of range of motion of elbow, forearm and wrist<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| proportional ulnar length (PUL) | proportional ulnar length (PUL) is the ratio between ulnar lenght and the height of the patient | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| genotype | identify potential association among the genotypic pattern (EXT1 or EXT2) and phenotypic presentation | 1 year | 
| forearm function | elbow, forearm and wrist range of motion (ROM) measured by a goneometer | 1 year | 
| EuroQol 5D | EQ-5D is a standardised measure of health-related quality of life developed by the EuroQol Group | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Multiple Hereditary Exostoses, forearm, height, ulnar length