Congenital trigeminal anaesthesia.

Two patients with congenital trigeminal nerve anaesthesia are described. The first (male, aged 14 years) had an isolated unilateral loss of sensation in all three divisions of the trigeminal nerve with no other abnormalities. The second patient (male, aged 3 years 6 months) had bilateral loss of sensation in all three divisions of the trigeminal nerve, associated with other neurological abnormalities. No explanation for their abnormalities was found. The Rosenberg classification of congenital trigeminal anaesthesia is discussed with reference to these patients and also with reference to the developmental biology of the trigeminal nerve.