[1] Inst Mexicano Seguro Social, Coordinac Invest Salud, Ctr Med Nacl Siglo 21, Unidad Invest Med Biol Desarrollao, Mexico City 06703, DF, Mexico
[2] Inst Mexicano Seguro Social, Hosp Pediat, Ctr Med Nacl Siglo 21, Unidad Invest Med Genet Humana, Mexico City, DF, Mexico
[3] Inst Nacl Ciencias Med & Nutr Salvador Zubiran, Unidad Biol Mol & Med Genom, Mexico City, DF, Mexico
[4] Ctr Invest Reg Dr Hideyo Noguchi, Dept Salud Reprod & Genet, Reprod Biol Lab, Mexico City, DF, Mexico