ellite ▁DNA ▁and ▁ST S ▁markers ▁as ▁well ▁as ▁compar ative ▁genom ic ▁hy brid ization ▁( CG H ) ▁studies ▁using ▁DNA ▁micro array s . ▁In ▁some ▁cases ▁PC R ▁and ▁sequ encing ▁of ▁the ▁entire ▁SO X 9 ▁gene ▁is ▁used ▁to ▁diagn ose ▁C MD . ▁Many ▁different ▁trans location ▁break points ▁and ▁related ▁chrom os om al ▁aber r ations ▁in ▁patients ▁with ▁C MD ▁have ▁been ▁identified . ▁ ▁Pro gn osis ▁In ▁nearly ▁ 9 5 % ▁of ▁the ▁cases , ▁death ▁occurs ▁in ▁the ▁ne on atal ▁period ▁due ▁to ▁resp ir atory ▁dist ress , ▁generally ▁related ▁to ▁small ▁ch est ▁size ▁or ▁ins u fficient ▁development ▁of ▁the ▁tra che a ▁and ▁other ▁upper ▁air way ▁structures . ▁▁▁ ▁Among ▁surv iv ors ▁of ▁C MD , ▁the ▁ske let al ▁mal form ations ▁change ▁over ▁time ▁to ▁include ▁w ors ening ▁sc ol ios is ▁or ▁k y ph osis ▁resulting ▁in ▁decre ased ▁tr unk ▁size ▁relative ▁to ▁the ▁lim b ▁length . ▁Ne uro log ical ▁damage ▁is ▁also ▁often ▁seen ▁including ▁mental ▁ret ard ation ▁and ▁de af ness . ▁Even ▁among ▁surv iv ors ▁of ▁the ▁pr en atal ▁period , ▁C MD ▁patients ▁have ▁short ened ▁life ▁sp ans ▁due ▁to ▁lif el ong ▁resp ir atory ▁issues . Th ose ▁patients ▁with ▁ambigu ous ▁gen ital ia ▁or ▁sex ▁revers al ▁at ▁birth , ▁of ▁course , ▁maintain ▁that ▁state , ▁and ▁are ▁either ▁ster ile