Down Syndrome (Trisomy 21)
Extra genetic material on chromosome 21 or translation of additional chromosome 21 onto another chromosome. 1 in 600-1000 live births. Increased incidence with increase maternal age (~1 in 32 live births at age 45). Originally described by John Down in 1866.
Variably characterised by small ears, large tongue, flat appearance to face, mongolian slant to eyes, short broad neck, congenital heart disease (may cause death in infancy), hypothyroidism, deafness, intellectual disability, sensory abnormalities, visual impairments, premature aging; muscle hypotonia and ligamentous laxity.
Physical development is delayed.
An arthropathy, clinically similar to juvenile chronic arthritis is common.
Hallux abducto-valgus; metatarsus primus adductus; flat pronated feet; shoe fitting problems; abducted gait and wider base of support; Simian crease; abnormal dermatoglyphics.
Excessive external hip rotation; lack of trunk rotation; wide base of gait; inadequate heel contact during gait; decreased ankle ROM; poor foot clearance during swing phase.