Abstract: The invention provides methods of treating schizophrenia in a subject, including for example, administering to the subject an agent that inhibits expression or activity of a C4A polynucleotide or polypeptide. The invention also provides methods of identifying a subject having or at risk of developing schizophrenia involving measuring or detecting an alteration in the level, copy number, and/or sequence of complement component C4A or complement component C4B relative to a reference.

Abstract: The present invention provides CSF protein-based biomarkers and biomarker combinations that are useful in diagnosing dementia or a dementia related neurological disorder a patient. In particular, the biomarkers of this invention are useful to classify a subject sample as Alzheimer's dementia, non-Alzheimer's dementia, as Progressive supranuclear palsy (PSP), non-PSP dementia or normal. In some aspects, the invention relates to methods useful for diagnosing, classifying, and profiling dementia or a dementia related neurological disorder a patient.

Abstract: C1q is shown to be expressed in neurons, where it acts as a signal for synapse elimination. Methods are provided for protecting or treating an individual suffering from adverse effects of synapse loss. These findings have broad implications for a variety of clinical conditions, including Alzheimer's disease.