Autistic Disorder|Breast Neoplasms|Confidence Intervals|DNA Probes|DiGeorge Syndrome|Gene Dosage|Genetic Markers|Genetic Predisposition to Disease|Genetic Variation|Humans|Linear Models|Molecular Probe Techniques|Polymerase Chain Reaction|Prader-Willi Syndrome|Predictive Value of Tests|Reference Standards|Reference Values|Single-Blind Method|Stochastic Processes