Flashcards on Congenital Malformations of Pediatric Wrist and Forearm
Pediatric Wrist & Forearm Malformations: A Student Guide
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Hereditary multiple exostoses
39 cards
Card 1
Question: What is hereditary multiple exostoses (HME)?
Answer: An inheritable disorder of enchondral bone growth characterized by multiple cartilaginous exostoses (osteochondromas) growing from physes of long bone
Card 2
Question: How is HME inherited?
Answer: Autosomal dominant with high penetrance and variable expressivity.
Card 3
Question: List other names that have been used for HME.
Answer: Multiple cartilaginous exostoses, diaphyseal aclasis, dyschondroplasia, hereditary deforming chondrodysplasia, and osteochondromatosis.
Card 4
Question: Which condition is frequently confused with HME but is entirely different?
Answer: Multiple enchondromatosis (Ollier’s disease).
Card 5
Question: What other conditions can include multiple exostoses?
Answer: Metachondromatosis and Langer-Giedion syndrome.
Card 6
Question: What is the approximate prevalence of HME?
Answer: About 1 in 50,000.
Card 7
Question: Which bones and sites are most commonly involved in HME?
Answer: Knee, humerus, hip, scapula, ribs, distal radius and ulna, ankle, elbow, hands, feet, and pelvis.
Card 8
Question: Approximately what fraction of patients with HME have forearm involvement?
Answer: About half of all patients.
Card 9
Question: What genes are implicated in HME and what is their general function?
Answer: EXT genes (located on different chromosomes); they are tumor suppressor genes.
Card 10
Question: Why has HME been classified as a familial neoplastic syndrome?
Answer: Because the EXT genes involved are tumor suppressor genes, linking the condition to neoplastic behavior.