Pectus excavatum is also a relatively common symptom of Marfan syndrome[12] and Loeys-Dietz syndrome and sometimes is found in other connective tissue disorders such as Ehlers–Danlos Syndrome.[13] Many children with spinal muscular atrophy develop pectus excavatum due to the diaphragmatic breathing that is common with the disease. Pectus excavatum also occurs in about 1% of persons diagnosed with celiac disease for unknown reasons.[citation needed]