Disease Directory West Syndrome
Neurological

West Syndrome

Also known as: Infantile spasms, IS, hypsarrhythmia with epileptic spasms

Prevalence

1-5 per 10,000 (Orphanet)

Onset

Infantile

Type

Multiple etiologies (structural, genetic, metabolic, unknown)

Gene

Multiple (CDKL5, ARX, STXBP1, TSC1/TSC2 and others)

About West Syndrome

West syndrome (infantile spasms) is an age-specific severe epileptic encephalopathy defined by the triad of epileptic spasms (clusters of brief flexion or extension jerks), hypsarrhythmia on EEG (chaotic high-voltage slow waves with multifocal spikes), and developmental arrest or regression. Onset peaks between 4-8 months of age. ACTH and vigabatrin are established first-line treatments; early treatment initiation is critical for developmental outcomes.

Common Clinical Features

Epileptic spasms in clusters Hypsarrhythmia on EEG Developmental arrest or regression Head drops Arm extension and flexion jerks Irritability Loss of social smile

Clinical Trial Eligibility Tips

What to know before applying to West Syndrome trials.

EEG-confirmed hypsarrhythmia and video-EEG documentation of spasm clusters are required for trial enrollment

Age at spasm onset and time from onset to treatment initiation affect prognosis and trial eligibility windows

Prior ACTH or vigabatrin treatment response history is a critical eligibility factor

Underlying etiology (TSC, genetic, structural, cryptogenic) determines eligibility for etiology-specific trials versus general infantile spasm trials

Patient Resources

Patient Organization

Infantile Spasms Alliance

Visit website ↗

Orphanet

European reference resource for rare diseases (ORPHA:3451)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

Search NORD ↗

Find recruiting West Syndrome trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for West Syndrome. Updated daily.

Related Rare Diseases