Abstract: The ACP1 *A allele provides a means for diagnosing susceptibility of a human subject to hyperlipidemia, especially hyperlipidemia associated with metabolic syndrome, a means for treating, or preventing the onset of, hyperlipidemia and metabolic syndrome, and a means for screening and identifying drugs suitable for use in treating or preventing hyperlipidemia, especially hyperlipidemia associated with metabolic syndrome. Diagnostic kits are also provided.

Abstract: The invention is the discovery of a single nucleotide polymorphism in the gene coding for lymphoid tyrosine phosphatase. This SNP leads to a mutation in the lymphoid tyrosine phosphatase protein that prohibits binding with the SH3 domain of Csk, and leads to a subsequent dysregulation of the T-Cell activation cascade. Such dysregulation can lead to a variety of autoimmune disorders. Thus, the invention provides a series of useful methods for diagnosing, discovering modulators, developing treatments and providing research tools. Also, the invention provides compositions of matter useful for research and useful for the diagnosis and treatment of these disorders.

Abstract: The ACP1 *A allele provides a means for diagnosing susceptability of a human subject to hyperlipidemia, especially hyperlipidemia associated with metabolic syndrome, a means for treating, or preventing the onset of, hyperlipidemia and metabolic syndrome, and a means for screening and identifying drugs suitable for use in treating or preventing hyperlipidemia, especially hyperlipidemia associated with metabolic syndrome. Diagnostic kits are also provided.