Newborn screening together with access to disease-modifying therapies can reduce the functional burden of spinal muscular atrophy (SMA) and the effect of other conditions associated with it on affected children, according to a new study published in The Lancet, Child and Adolescent Health.
The scales that have clinical use in determining clinical independence for children who are diagnosed through newborn screening are motor score, compound muscle action potential, and disease status at diagnosis, the authors noted.
Read more about the early signs of SMA
To investigate the effectiveness of newborn screening and access to disease-modifying therapies in the real world, a team of researchers led by Michelle A Farrar, PhD, from the Department of Neurology, Sydney Children’s Hospital Network, in Australia, conducted a prospective, nonrandomized cohort study in 33 children with SMA.
All children were under 16 years of age and had a homozygous mutation in the SMN1 gene. Of these 15 children were diagnosed with the disease by newborn screening between August 2018 and August 2020 and 18 children were diagnosed by clinical referral between August 2016 and July 2018.
The 2-year survival rate was 93% in children who were diagnosed by newborn screening and 89% in those diagnosed by referral.
Among children who survived, 79% of those diagnosed via newborn screening walked independently or with assistance while only 6% of those diagnosed by referral did so.
There was a significantly bigger change in motor function as measured by the Hammersmith Infant Neurological Examination-2 (HINE-2) score between the 2 groups over 2 years.
Moreover, more children diagnosed by referral needed nonintensive ventilation or feeding support at follow-up compared to children diagnosed by newborn screening.
The authors identified the HINE-2 score, The Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders, compound muscle action potential, and disease status at diagnosis as significant predictors of functional motor outcomes.
Kariyawasam DS, D’Silva AM, Sampaio H, et al. Newborn screening for spinal muscular atrophy in Australia: a non-randomised cohort study. Lancet Child Adolesc Health. Published online January 17, 2023. doi:10.1016/S2352-4642(22)00342-X