<unk>  or longitudinal<unk>  deficiency is "the congenital absence of the<unk> and it is the most common congenital absence of long bone of the extremities." It is the shortening of the<unk> at birth, or the complete lack thereof.<unk>  often causes severe knee instability due to deficiencies of the ligaments. Severe forms of<unk>  can result in a malformed ankle with limited motion and stability. Fusion or absence of two or more toes are also common. In humans, the disorder can be noted by ultrasound in utero to prepare for amputation after birth or complex bone lengthening surgery. The amputation usually takes place at six months with removal of portions of the legs to prepare them for prosthetic use. The other treatments, which include repeated corrective osteotomies and leg-lengthening surgery (Ilizarov apparatus), are costly and associated with residual deformity.
Fibular hemimelia
Optokinetic drum
Spotted lunulae
Morning glory disc anomaly
Macrostomia
Acrocephalosyndactylia
Macular hypoplasia
Vitreomacular adhesion