The Eighth Circuit rejected the asylum claim from an applicant who was threatened with harm by the MS-13 gang because his cousin was a member of a rival gang. Members of MS-13 shot his cousin in front of his home and warned him never to return. The Immigration Judge granted asylum on a family-based social group (male, gang-aged family members of his cousin Oscar). The Board of Immigration Appeals reversed, and the Eighth Circuit affirmed, noting that "an alien’s membership in a family that experienced gang violence lacks the visibility and particularity required to constitute a social group under the statute."
The full text of Aguinada-Lopez v. Lynch can be found here: http://media.ca8.uscourts.gov/opndir/16/02/151095P.pdf