A treatable inborn error of metabolism presenting in the sixth decade.

Phenylketonuria (PKU) is an inborn error of amino acid metabolism. If untreated, PKU can result in global developmental delay, learning difficulties or seizures. For that reason, PKU is included in the UK neonatal screening programme.

The Guillain-Mollaret triangle in action.

The Guillain-Mollaret triangle comprises the ipsilateral red nucleus in the midbrain, the inferior olive in the medulla and the contralateral dentate nucleus in the cerebellum: together, these form the dentato-rubro-olivary pathway. Pathology in this triangle disinhibits (and so activates) the inferior olivary nucleus. The olivary nucleus then hypertrophies and its rhythmical discharges may manifest clinically as oculopalatal tremor.

A question of taste.

A 38-year-old woman presented with bilateral lower facial weakness and reduced taste, but preserved involuntary facial movements and smell.