= rare autosomal recessive disorder presumably on the basis of abnormal neural crest development

Age: presenting at birth

Prevalence: 15 reported cases

Path: absence of dorsal + sympathetic ganglia, deficiency of neural fibers <6 µm in diameter + disproportionate number of fibers of 6–10 µm in diameter

• history of painless injuries + burns (DDx: familial dysautonomia, congenital sensory neuropathy, hereditary sensory radicular neuropathy, acquired sensory neuropathy, syringomyelia)
• abnormal pain + temperature perception
• burns, bruises, infections (common); absence of sweating
• biting injuries of fingers, lips, tongue; mental retardation

Criteria:

1. defect must be present at birth
2. general insensitivity to pain
3. general mental / physical retardation

• epiphyseal separation in infancy → epiphyseal injuries → growth problems
• metaphyseal fractures in early childhood
• diaphyseal fractures in late childhood
• Charcot joints = neurotrophic joints (usually weight-bearing joints) with effusions + synovial thickening
• ligamentous laxity
• bizarre deformities + gross displacement + considerable hemorrhage ← unnoticed fractures + dislocations
• ± osteomyelitis + septic arthritis → may progress extensively

DDx:

1. Sensory neuropathies (eg, diabetes mellitus)
2. Hysteria
3. Syphilis
4. Mental deficiency
5. Syringomyelia
6. Organic brain disease