Trisomy 18, also known as Edward's Syndrome, is a chromosomal abnormality that often results in stillbirth or an early death of an infant. Learn more about the symptoms, causes, diagnosis, and Author: Stephanie Watson. Triple X syndrome, also called trisomy X or 47,XXX, is characterized by the presence of an additional X chromosome in each of a female's cells. Although females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features.
Sex chromosome, either of a pair of chromosomes that determine whether an individual is male or female. The sex chromosomes of human beings and other mammals are designated by scientists as X and Y. In humans the sex chromosomes comprise one pair of the total of 23 pairs of chromosomes. An allosome (also referred to as a sex chromosome, heterotypical chromosome, heterochromosome, or idiochromosome) is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction.
Dec 07, 2016 · 47 XXX syndrome, also called trisomy X or triple X syndrome, is characterized by the presence of an additional (third) X chromosome in each of a female's cells (which normally have two X chromosomes). An extra copy of the X chromosome is associated with tall stature, learning problems, and other features in some girls and women. Humans have 23 pairs of chromosomes. A trisomy is a chromosomal disorder characterised by an additional chromosome, so the person has 47 instead of 46. Down syndrome, Edward syndrome and Patau syndrome are the most common forms of trisomy. Genes Page last reviewed: 29 Aug 2013.