[1] IMSS, Unit Med Invest Human Genet, Children Hosp, Med Ctr S 21, Mexico City, DF, Mexico
[2] IMSS, Dept Surg Oncol, Children Hosp, Med Ctr S 21, Mexico City, DF, Mexico
[3] IMSS, Dept Pathol, Children Hosp, Med Ctr S 21, Mexico City, DF, Mexico
[4] IMSS, Dept Pediat Surg, Gen Hosp, Med Ctr La Raza, Mexico City, DF, Mexico