Researchers are unsure of the cause of<unk> . Some researchers take the stance that it is a congenital disorder (birth defect), but not genetic. Others assume that there is some genetic component. A small sample size test found that in at least some cases, 37% of individuals have an affected first degree family member. As of 2012, a number of genetic markers for<unk>  have also been discovered. It was believed for decades that<unk>  is caused by an overgrowth of costal cartilage, however people with<unk>  actually tend to have shorter, not longer, costal cartilage relative to rib length.<unk>  can be present in other conditions too, including Noonan syndrome, Marfan syndrome and Loeys–Dietz syndrome as well as other connective tissue disorders such as Ehlers–Danlos syndrome. Many children with spinal muscular atrophy develop<unk>  due to their diaphragmatic breathing.
Pectus excavatum
Pectus carinatum
Pes cavus
Pediculosis pubis
Morsicatio buccarum
Protrusio acetabuli
Subungual hematoma
Pediculosis corporis