Hereditary spastic paraplegia refers to a group of disorders characterized by progressive spasticity of lower extremities. The Genetic Nomenclature Study Group found differing frequency of variant types across 3 HSP genes: ATL1, SPAST and REEP1.

The PubMed literature search and articles obtained through additional sources yielded a total of 239 articles for HSP–ATL1, of which 70 were eligible, 531 articles for HSP–SPAST, for which 187 were eligible, and 334 articles for HSP–REEP1, of which 31 were eligible (Fig. 1, Supplementary File_HSP Article Screening Log).

By classifying these articles according to study type, we found that the most common were genetic screening studies (36.3%), family studies (30.4%), followed by, case reports/series (23.2%), and other/mixed-type studies (10.0%). While genetic screening studies were the most common study type for HSP–SPAST and HSP–REEP1, family studies were the most common study type for HSP–ATL1 (Table S2).