<unk>  is mainly characterized by the fusion of both legs with rotation of the fibula. It may include the absence of the lower spine, as well as abnormalities of the pelvis and renal organs. It was previously thought to be a severe form of sacral agensis/caudal regression syndrome, but more recent research confirms that these two conditions are not related. NORD has a separate report on caudal regression syndrome. In general, the more severe cases of limb fusion correlate with more severe dysplasia in the pelvis. Rather than the two iliac arteries present in fetuses with complete renal agenesis, fetuses with<unk>  display no branching of the abdominal aorta, which is always absent. Associated defects recorded in cases of<unk>  include neural tube defects (rachischisis, anencephaly, and spina bifida), holoprosencephaly, hypoplastic left heart syndrome, other heart defects, esophageal atresia, omphalocele, intestinal malrotation, persistent cloaca, and other limb defects (most commonly absence of the radius).
Sirenomelia
Rhizomelia
Mesomelia
Dolichostenomelia
Phocomelia
Meromelia
Loxoscelism
Adiposogenital dystrophy