Enrichment in this large adult Ashkenazi exome database reinforces recent publications of founder mutations for rare pediatric disorders including FKTN (Walker Warburg syndrome)[16], CCDC65 (Primary ciliary dyskinesia)[17], TMEM216 (Joubert syndrome)[18], C11orf73 (Leukoencephalopathy)[19]; PEX2 (Zellweger syndrome)[20], VPS11 (Hypomyelination and developmental delay)[21] and BBS2 (Bardet-Biedl syndrome)[22]. The gene discussed is PEX2; the disease is muscular dystrophy-dystroglycanopathy, type A.