Trisomy 15

Classification according to ICD-10
Q92.0	Complete trisomy, meiotic nondisjunction
Q92.1	Complete trisomy, mosaic (mitotic nondisjunction)
Q92.2	Partial trisomy, major form A whole arm or more doubled
Q92.3	Partial trisomy, minor form Less than a whole arm doubled
Q92.4	Chromosome duplications that are only visible in the prometa phase
Q92.5	Chromosome duplications, with other complex rearrangements
ICD-10 online (WHO version 2019)

A trisomy 15 is a by tripling ( trisomy caused) of genetic material of chromosome 15 genomic mutation . It is rare and the majority of it is fatal during pregnancy .

to form

A trisomy 15 is genetically characterized in that chromosome 15 or a part of it is present three times (= trisome ) instead of usually two times (= disome) in all or in part of the body cells. There are four types of trisomy 15:

1. Free trisomy 15 : Type in which chromosome 15 is completely trisome in all body cells . The karyotype of free trisomy 15 is: 47, XX + 15 or 47, XY + 15 ([karyogram]).
2. Translocation trisomy 15 : Type in which chromosome 15 is completely trisome in all body cells, but one of chromosomes 15 has attached to another chromosome. A chromosome shift is called a translocation in genetics .
3. Mosaic trisomy 15 : Type in which chromosome 15 is not present in triplicate (trisome) in all body cells, but at the same time a cell line with the usual disomic set of chromosomes exists. The presence of several karyotypes within an organism is called a mosaic in genetics . The karyotype of the mosaic trisomy 15 is: 46, XX / 47, XX + 15 and 46, XY / 47, XY + 15, respectively.
4. Partial trisomy 15 : Type in which chromosomes 15 are present twice (disome) in all body cells, as usual, but part ( part ) of one of the two chromosomes 15 is doubled , which means that one of chromosomes 15 is slightly longer than the other. The hereditary information in this section is therefore available three times (trisom).

forecast

While children with free trisomy 15 and translocation trisomy 15 are not viable, with the mosaic type and partial trisomy 15, depending on the proportion and effect of the trisome chromosome material, longer survival is possible with adequate treatment of any organ malformations that may be present.

Symptoms

Due to the rare occurrence of trisomy 15, few features are documented that have been observed in affected fetuses. These include heart defects , increased neck transparency , flexion contracture of the fingers (fingers crossed) and slowed growth. Newborns usually have skull and facial malformations, malformations of fingers or toes, scoliosis , malformations in the genital area (especially in boys). Babies usually have generalized muscle hypotension , cognitive disabilities become apparent as they get older, and epilepsy can occur.

Web links

• Surgical treatment of epilepsy in trisomy 15. A case report ( Memento of 28 September 2007 at the Internet Archive ) (Engl.)
• Prader-Willi syndrome in a child with mosaic trisomy 15 mosaic Triplo-X: A molecular analysis (Engl.)

literature

• Bennett CP, Davis T., MJ Seller: Trisomy 15 mosaicism in an IVF fetus. In: Journal of Medical Genetics . (1992); 29 (10), pp. 745-746.
• SL Christian, AC Smith, M. Macha, SH Black, FF Elder, JM Johnson, RG Resta, U. Surti, L. Suslak, S. Coldwell, B. Fitzgerald, JM Semmens et al: A case of trisomy of chromosome 15. In: J Med Genet. 1981; 18, pp. 146-148.
• JA Kuller, SA Laifer: Trisomy 15 associated nonimmune hydrops. In: Am J Perinatol. 1991; 8, pp. 39-40.
• J. Lahdetie, T. Lakkala, P. Aula: Mosaic trisomy 15, a case report. In: Am J Hum Genet. 1991; 49 (Suppl), p. 269.

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