A point mutation is when a single base pair is altered. Point mutations can have one of three effects. First, the base substitution can be a silent mutation where the altered codon corresponds to the same amino acid. Second, the base substitution can be a missense mutation where the altered codon corresponds to a different amino acid. Or third, the base substitution can be a nonsense mutation where the altered codon corresponds to a stop signal.
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Point mutations are a large category of mutations that describe a change in single nucleotide of DNA, such that that nucleotide is switched for another nucleotide, or that nucleotide is deleted, or a single nucleotide is inserted into the DNA that causes that DNA to be different from the normal or wild type gene sequence.
Leslie G. Biesecker, M.D.
Chief and Senior Investigator, Genetic Disease Research Branch; Head, Human Development Section and Physician Scientist Development Program
Dr. Biesecker's research focuses on the clinical and molecular delineation of human malformation syndromes. Currently, his laboratory is working on two classes of disorders, classic multiple congenital anomaly syndromes and segmental overgrowth disorders. The goals of his research program are to improve the medical care of patients affected by these disorders, provide generalized knowledge about the broad field of birth defects, and better understand basic mechanisms of normal and abnormal human development. Dr. Biesecker's group studies several multiple congenital anomaly syndromes, including Pallister-Hall syndrome, McKusick-Kaufman syndrome, Bardet-Biedl syndrome and Lenz microphthalmia syndrome.