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				[ What is a chromosome? ][ What is a gene? ][ What is a locus? ] [ What is schizophrenia? ][ What is 22q Deletion Syndrome? ] What is a chromosome? [ top ] Chromosomes are found in every cell of the human body (except red blood cells). Chromsomes are packages of genes, which are made of deoxyribonucleic acid (DNA). DNA is the genetic material that acts as a "blueprint" for our body to grow, develop and function. We have 2 copies of each chromosome in every cell of our bodies (except reproductive cells) for a total of 46 chromosomes. We inherit one copy from our mother and the other copy from our father. We number them from the largest to the smallest, namely chromosome 1 to 22. The last pair of chromosomes is known as the sex chromosomes as they determine whether we are male or female. What is a gene? [ top ] Genes are the actual instructions that are found scattered along each chromosome; sometime we think of this as beads on a string. Each chromosome contains several hundred to thousands of genes. Each gene has a specific job or function. For instance, some genes contribute to determining height, whereas other genes are involved in controlling brain development. What is a locus? [ top ] The position or location of a gene on a chromosome. (The plural of locus is loci.) What is schizophrenia? [ top ] Schizophrenia is a brain disease. About 1 percent of the population develop schizophrenia during their lifetime. Symptoms can include delusions (false beliefs), hallucinations (false perceptions), disordered thinking, social and emotional withdrawal, and decreased social and vocational functioning. The onset of illness varies from childhood (rare) to elderly (also rare), with most individuals becoming ill in their late teen to early adult years. Schizophrenia is a treatable illness. Available treatments can alleviate many of the symptoms in most people. What is 22q11 Deletion Syndrome? [ top ] 22q Deletion Syndrome (22qDS), also known as velocardiofacial syndrome (VCFS) or DiGeorge syndrome, is a genetic syndrome (collection of features) associated with a deletion (missing information) on one of the pair of chromosomes 22. Individuals with 22qDS can have multiple features that may include congenital (present at birth) heart defects, other birth defects, characteristic but subtle facial features, learning difficulties, and speech difficulties.  About one in four individuals with 22qDS develop schizophrenia.  Adults with 22qDS may have some, but not all of the 43 features that are common in this condition.
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