<unk> , also called<unk>  dysostosis, is a hereditary congenital disorder characterized by clavicular hypoplasia oragenesis, narrowed thorax that allows approximation the shoulders in front of the chest, delayed closure of the cranial sutures and fontanelles, Wormian bones, short stature, delayed eruption of secondary teeth, and other skeletal abnormalities. The fontanelles may remain open until adulthood, but the sutures often close with interposition of Wormian bones. Bosses of the frontal, parietal, and occipital regions give the skull a large globular shape with small face. The characteristic skull abnormalities are sometimes referred to as the "Arnold head" named after the descendants of a Chinese who settled in South Africa and changed his name to Arnold. More than 100 additional anomalies may be associated, including wide pubic symphysis, dental abnormalities, short middle phalanges of the fifth fingers, delayed skeletal maturation, hearing deficiency, and mild mental retardation in some cases. It was originally found to involve only bones of membranous origin. However, more recent clinical studies suggest that it is a generalized skeletal disorder that affects the entire skeleton and is therefore considered to be a<unk>  rather than a dysostosis.
Cleidocranial dysplasia
Schizencephaly
Lissencephaly
Spina bifida
Cerebral palsy
Holoprosencephaly
Hydranencephaly
Megalencephaly