The diagnosed prevalent cases of type II spinal muscular atrophy (SMA) made up the highest proportion with 10,574 cases, nearly one half of all diagnosed prevalent cases of SMA in the seven major markets (7MM*) in 2018, according to GlobalData, a leading data and analytics company.

More than one third of type II SMA cases, which was around 4,136 cases, were contributed by the US followed by Japan. Type IV SMA had the least amount of cases among the subtypes which was only one tenth of all diagnosed prevalent cases of SMA.

The company’s latest report: ‘Spinal Muscular Atrophy: Epidemiology Forecast to 2028’ reveals that the increased burden of type II SMA cases is partly attributable to the high mortality of type I SMA combined with the increased frequency of the specific type II SMA phenotype due to gene mutations.

Diagnosed prevalent cases of SMA are set to increase in the 7MM from 25,783 cases in 2018 to 26,690 in 2028, at an Annual Growth Rate (AGR) of 0.35%.

Shilpa Shaji, Epidemiologist for GlobalData, comments: “The introduction of new therapies for treating SMA is likely to impact the prevalence of SMA. As more people become aware of the disease, diagnosis and patient enrolment in registries may improve. This could have significant resource implications for health care planning.”

*7MM: US, France, Germany, Italy, Spain, the UK and Japan