Glycine encephalopathy

4 cases of nonketotic hyperglycinemia (glycine encephalopathy), one with autopsy, are presented and the literature on 61 cases is reviewed. Major clinical signs include early hypotonia, lethargy and erratic and massive myoclonias with respiratory distrubances, starting during the first days of life after a symptom-free interval. Early death is common. Survivors are severely retarded and exhibit various types of seizures including infantile spasms. The EEG pattern consists initially of periodical paroxysmal bursts on an almost flat tracing, evolving later into a hypsarrhythmic pattern. Spongiosis of the myelinated pathways is the main pathological finding. Elevated CSF glycine seems to be the essential determinant of the neurological disturbances and it is, therefore, suggested that the term glycine encephalopathy be used instead of non-ketotic hyperglycinemia. A classification of disorders associated with hyperglycinemia is proposed

Paroxysmal extreme pain disorder (previously familial rectal pain syndrome)

OBJECTIVE: To describe the clinical phenotype of paroxysmal extreme pain disorder (previously called familial rectal pain syndrome), an autosomal dominant condition recently shown to be a sodium channelopathy involving SCN9A. METHODS: An international consortium of clinicians, scientists, and affected families was formed. Clinical details of all accessible families worldwide were collected, including age at onset, features of attacks, problems between attacks, investigational results, treatments tried, and evolution over time. A validated pain questionnaire was completed by 14 affected individuals. RESULTS: Seventy-seven individuals from 15 families were identified. The onset of the disorder is in the neonatal period or infancy and persists throughout life. Autonomic manifestations predominate initially, with skin flushing in all and harlequin color change and tonic attacks in most. Dramatic syncopes with bradycardia and sometimes asystole are common. Later, the disorder is characterized by attacks of excruciating deep burning pain often in the rectal, ocular, or jaw areas, but also diffuse. Attacks are triggered by factors such as defecation, cold wind, eating, and emotion. Carbamazepine is effective in almost all who try it, but the response is often incomplete. CONCLUSIONS: Paroxysmal extreme pain disorder is a highly distinctive sodium channelopathy with incompletely carbamazepine-sensitive bouts of pain and sympathetic nervous system dysfunction. It is most likely to be misdiagnosed as epilepsy and, particularly in infancy, as hyperekplexia and reflex anoxic seizures