cle ▁that ▁separ ates ▁the ▁ab d omen ▁from ▁the ▁ch est ▁cav ity ▁( the ▁dia ph rag m ), ▁which ▁is ▁called ▁a ▁dia ph rag m atic ▁h ern ia . ▁This ▁potentially ▁serious ▁birth ▁defect ▁allows ▁the ▁st om ach ▁and ▁int est ines ▁to ▁move ▁into ▁the ▁ch est ▁and ▁possibly ▁crowd ▁the ▁developing ▁heart ▁and ▁l ungs . ▁An ▁opening ▁in ▁the ▁wall ▁of ▁the ▁ab d omen ▁( an ▁om ph alo ce le ) ▁that ▁allows ▁the ▁ab dom inal ▁org ans ▁to ▁pro tr ude ▁through ▁the ▁nav el ▁may ▁also ▁occur ▁in ▁affected ▁individuals . ▁Occ asion ally ▁people ▁with ▁Don na i – B arrow ▁synd rome ▁have ▁ab normal ities ▁of ▁the ▁int est ine , ▁heart , ▁or ▁other ▁org ans ▁and ▁sc ol ios is . ▁ ▁C aus es ▁Mut ations ▁in ▁the ▁L R P 2 ▁gene ▁cause ▁Don na i – B arrow ▁synd rome . ▁The ▁L R P 2 ▁gene ▁provides ▁instructions ▁for ▁making ▁a ▁protein ▁called ▁meg alin , ▁which ▁functions ▁as ▁a ▁re ceptor . ▁Re ceptor ▁prote ins ▁have ▁specific ▁sites ▁into ▁which ▁certain ▁other ▁prote ins , ▁called ▁lig ands , ▁fit ▁like ▁keys ▁into ▁lo cks . ▁T ogether , ▁lig ands ▁and ▁their ▁re cept ors ▁trigger ▁signals ▁that ▁affect ▁cell ▁development ▁and ▁function . ▁Meg alin ▁has ▁many ▁lig ands ▁involved ▁in ▁various ▁body ▁processes , ▁including ▁the ▁absor ption ▁of ▁vit am ins ▁A ▁and ▁D