🦴 Chapter 735 · General Considerations in Skeletal Dysplasias

Nelson Textbook of Pediatrics 22nd Edition | Skeletal dysplasias (chondrodysplasias) — genetic disorders of cartilage and bone, incidence ~1/4000 births. FGFR3 group: achondroplasia (most common), thanatophoric dysplasia (lethal), hypochondroplasia. Type 2 collagenopathies: spondyloepiphyseal dysplasia (SED) congenita, Kniest, Stickler. Metaphyseal dysplasias: Schmid type. Osteogenesis imperfecta (bone fragility). Lethal neonatal dysplasias: thanatophoric dysplasia, achondrogenesis type II, osteogenesis imperfecta type II. Treatment: vosoritide (CNP analogue) for achondroplasia (age ≥5 years), supportive care, genetic counseling.

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📋 30 Clinical Scenarios — Skeletal Dysplasias

📇 High‑Yield Review Cards

🩺 Clinical Recognition: Skeletal Dysplasias

Select a presentation to review diagnostic clues and management per Nelson Ch 735.

📋 Stepwise Management of Skeletal Dysplasias

🔑 Key Principles — Nelson Chapter 735
• Achondroplasia: Most common skeletal dysplasia. FGFR3 mutation (G380R). Rhizomelic shortening, macrocephaly, trident hands, midface hypoplasia. Treatment: vosoritide (CNP analogue, ≥5 years), monitor for spinal stenosis, foramen magnum stenosis. Avoid obesity.
• Thanatophoric dysplasia: Lethal neonatal dysplasia (FGFR3). Severe micromelia, narrow thorax, respiratory insufficiency.
• Type 2 collagenopathies (COL2A1): Spondyloepiphyseal dysplasia congenita (SED), Kniest, Stickler (myopia, retinal detachment, cleft palate).
• Skeletal survey: AP and lateral of all bones. Identify rhizomelic vs mesomelic vs acromelic shortening.
• Genetic counseling: Autosomal dominant (achondroplasia new mutation 80%), autosomal recessive, X-linked.

    ⚡ Reflex Prompts — Clinical Decisions

    📖 Summary: Skeletal Dysplasias (Nelson 735)