Classification and external resources
Patau syndrome, also known as trisomy 13, is a chromosomal abnormality, a syndrome in which a patient has an additional chromosome 13 due to a non-disjunction of chromosomes during meiosis. Chromosome 13 is one of the 23 pairs of Chromosomes in Humans People normally have two copies of this chromosome The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings Q00-Q89 - Congenital malformations and deformations (Q00-Q07 Nervous system ( Anencephaly and similar malformations Q00-Q89 - Congenital malformations and deformations (Q00-Q07 Nervous system ( Anencephaly and similar malformations The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors A chromosome is an organized structure of DNA and Protein that is found in cells. In Medicine and Psychology, the term syndrome refers to the association of several clinically recognizable features signs (observed by a physician Chromosome 13 is one of the 23 pairs of Chromosomes in Humans People normally have two copies of this chromosome Nondisjunction is the failure of chromosome pairs to separate properly during cell division Some are caused by Robertsonian translocations. Robertsonian translocation is a common form of chromosomal rearrangement that occurs in the five acrocentric human Chromosome pairs namely 13 14 15 21 and 22 The extra chromosome 13 disrupts the normal course of development, causing the characteristic features of Patau syndrome. Chromosome 13 is one of the 23 pairs of Chromosomes in Humans People normally have two copies of this chromosome Like all non-disjunction diseases (Down syndrome, Edwards syndrome, etc. Down syndrome, Down's syndrome, or trisomy 21 is a Chromosomal disorder caused by the presence of all or part of an extra 21st chromosome. Trisomy 18 or Edwards Syndrome is a Genetic disorder caused by the presence of all or part of an extra 18th chromosome. ), the risk of disease in the offspring increases with maternal age at pregnancy, with about 31 years being the average.  Patau syndrome affects approximately 1 in 12,000 live births.
Most cases of Patau's syndrome result from trisomy 13, which means each cell in the body has three copies of chromosome 13 instead of the usual two copies. A trisomy is a form of Aneuploidy with the presence of three copies instead of the normal two of a particular Chromosome. A small percentage of cases occur when only some of the body's cells have an extra copy of chromosome 13, resulting in a mixed population of cells with a differing number of chromosomes, such cases are called mosaic Patau.
Patau syndrome can also occur when part of chromosome 13 becomes attached to another chromosome (translocated) before or at conception. Affected people have two copies of chromosome 13, plus extra material from chromosome 13 attached to another chromosome. With a translocation, the person has a partial trisomy for chromosome 13 and often the physical signs of the syndrome differ from the typical Patau syndrome.
Most cases of Patau syndrome are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called non-disjunction can result in reproductive cells with an abnormal number of chromosomes. Nondisjunction is the failure of chromosome pairs to separate properly during cell division For example, an egg or sperm cell may gain an extra copy of chromosome 13. An ovum (plural ova) is a Haploid Female reproductive cell or Gamete. A spermatozoon or spermatozoan ( pl spermatozoa) from the Ancient Greek σπέρμα (seed and ζῷον (living being and more commonly known If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 13 in each of the body's cells.
Mosaic Patau syndrome is also not inherited. It occurs as a random error during cell division early in fetal development. A fetus (or foetus or fœtus) is a developing Mammal or other Viviparous Vertebrate, after the Embryonic stage and As a result, some of the body's cells have the usual two copies of chromosome 13, and other cells have three copies of the chromosome.
Patau syndrome due to a translocation can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 13 and another chromosome. This rearrangement is called a balanced translocation because there is no extra material from chromosome 13. Although they do not have signs of Patau syndrome, people who carry this type of balanced translocation are at an increased risk of having children with the condition.
Of those embryos that do survive to gestation and subsequent birth, common anomalies include:
Unless one of the parents are carriers of a translocation the chances of a couple having another trisomy 13 affected child is less than 1% (less than that of Down Syndrome). In Genetics, a chromosome translocation is a Chromosome abnormality caused by rearrangement of parts between nonhomologous Chromosomes. Down syndrome, Down's syndrome, or trisomy 21 is a Chromosomal disorder caused by the presence of all or part of an extra 21st chromosome.
Trisomy 13 was first observed by Erasmus Bartholin in 1657, but the chromosomal nature of the disease was ascertained by Dr. Rasmus Bartholin (Latinized Erasmus Bartholinus; August 13, 1625, Roskilde - † November 4, 1698, Kopenhagen Klaus Patau in 1960. Klaus Patau (1908–1975 was a German-born American Geneticist who in 1960 first reported the extra Chromosome in Trisomy 13.  The disease is named in his honor. Patau syndrome was also described in Pacific island tribes. These reports were thought to have been caused by radiation from atomic bomb tests. The tribes were temporarily moved before and during the test by an x amount of distance. They were then put back where they had been taken; all of this occurred before it was known how long, or even if, radiation still lingered on after a nuclear explosion.