Sleep disorders in succinic semialdehyde dehydrogenase deficiency: a family report.

BACKGROUND

Succinic semialdehyde dehydrogenase deficiency (SSADH) is a rare neurometabolic disorder involving the degradation of gamma-aminobutyric acid. Clinically, SSADH deficiency causes progressive or static encephalopathy with late infantile to early childhood onset. It is known that sleep disorders are a common clinical finding in these patients. However, very few studies have investigated sleep disorders with polysomnographies.

AIM OF THE STUDY: To analyze sleep disorders breathing, sleep architecture and paroxysmal EEG activity through polysomnographic recordings of two siblings suffering from SSADH deficiency

METHOD: Each patient underwent laboratory diurnal and overnight video-polysomnographic recordings in a room specially dedicated to mothers and their children.

RESULTS

The background EEG activity during quiet wakefulness consisted in abnormal, diffuse, low-voltage, disorganized slow theta waves. In both patients there was a general disorganisation of the sleep architecture with an increase of light sleep and a decrease of REM sleep. In patient 1, during sleep, there were 36 hypopneas, 13 central apneas and one obstructive apnea with a variable duration of 7-30s. The apnea/hypopnea index (AHI) was 7/h and oxygen saturation dropped to 80% during the respiratory events. In patient 2, the respiratory events consisted in 8 central apneas and 23 hypopneas of 6-20s; no obstructive apneas or hypopneas were observed. The oxygen saturation dropped to 90% during the apneas and the AHI was 5/h.

CONCLUSION

Sleep-disordered breathing (SDB) is a common finding in patients with SSADH deficiency and polysomnography recording is a useful tool for its diagnosis.