The focus of this work is a review of the literature to explore the frequency and severity of musculoskeletal abnormalities affecting lower limb structure and function in children and young adults with Down Syndrome (DS). Down Syndrome is associated with a variety of co-morbidities and musculoskeletal problems, with pes planus (flat feet) being the most commonly recognised lower limb problem, with a reported prevalence of 60-90%, compared to 3-15% in a non-DS paediatric population. In Down Syndrome pes planus is generally attributed to hypotonia and ligamentous laxity, were the noted prevalence is up to 90%. The almost universally reported joint laxity can be associated with delayed ambulation, an increased risk of a variety of musculoskeletal disorders and delayed acquisition of motor milestones. Other reported musculoskeletal lower limb and foot problems include postural alterations, gait imbalance, inflammatory arthritis, scoliosis, patella instability, hallux valgus and talipes equinovarus. Despite its high prevalence, pes planus appears to be either not rated as a problem or is under recognised. This may be attributed to the absence of a non-standardised approach to screening, assessment or classification of the severity of pes planus and a lack of a standardised care pathway that guides the management of these conditions in paediatric Down syndrome specifically.