NCT00568698.

Methods	A pilot therapeutic, randomised, placebo‐controlled, double‐blind trial using hydroxyurea in children with SMA type I
Participants	Children with SMA type I who never achieved independent sitting with an age of onset before 6 months and confirmation of a homozygous deletion or mutation of the SMN1 gene. Enrolment in study within 6 months after diagnosis up to 2 years of age and not requiring continuous respiratory support before the inclusion
Interventions	Hydroxyurea or placebo (dose route and duration of treatment not mentioned)
Outcomes	Adverse events; length of survival and age of ventilator dependence; motor unit number estimation; biomarker assays: SMN protein and SMN mRNA
Notes	This study is completed (last update received July 8, 2009 (www.clinicaltrials.gov), but results have not yet been published.

mRNA: messenger ribonucleic acid; SMA: spinal muscular atrophy; SMN: survival motor neuron