Polysomnographic abnormalities in succinic semialdehyde dehydrogenase (SSADH) deficiency.

OBJECTIVES

Patients with SSADH deficiency, a disorder of chronically elevated endogenous GABA and GHB, were studied for sleep symptoms and polysomnography. We hypothesized that patients would have excessive daytime somnolence and decreased REM sleep.

DESIGN

Polysomnography and MSLT were performed on patients enrolled for comprehensive clinical studies of SSADH deficiency.

SETTING

Sleep studies were obtained in the sleep laboratories at CNMC and NIH.

PATIENTS: Sleep recordings were obtained in 10 patients with confirmed SSADH deficiency.

INTERVENTIONS: Thirteen overnight polysomnograms were obtained in 10 patients (7 male, 3 female, ages 11-27 y). Eleven MSLT studies were completed in 8 patients.

MEASUREMENTS AND

RESULTS

Polysomnograms showed prolongation of REM stage latency (mean 272 +/- 89 min) and decreased percent stage REM (mean 8.9%, range 0.3% to 13.8%). Decreased mean sleep latency was present in 6 of 11 MSLTs.

CONCLUSIONS

SSADH deficiency is associated with prolonged latency to stage REM and decreased percent stage REM. This disorder represents a model of chronic GABA and GHB accumulation associated with suppression of REM sleep.