<Tr> <Th> Frequency </Th> <Td> 1 per 1,000 female births </Td> </Tr> <Tr> <Td_colspan="2"> (edit on Wikidata) </Td> </Tr> <P> Triple X syndrome, also known as trisomy X and 47 XXX, is characterized by the presence of an extra X chromosome in each cell of a female . Those affected are often taller than average . Usually there are no other physical differences and normal fertility . Occasionally there are learning difficulties, decreased muscle tone, seizures, or kidney problems . </P> <P> Triple X is due to a random event . Triple X can result either during the division of the mother's reproductive cells or during division of cells during early development . It is not typically inherited from one generation to the next . A form where only a percentage of the body cells contain XXX can also occur . Diagnosis is by chromosomal analysis . </P>

What happens when a female has an extra x chromosome
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