A Brief Overview on Autosomal Trisomies | Chapter 5 | Recent Developments in Medicine and Medical Research Vol. 15

 The presence of an extra chromosome to the normal diploid number is referred to as trisomy. It is the most frequent chromosomal number anomaly. Meiotic non-disjunction of chromosomes is the most common source of this numerical error, which results in a gamete with 24 instead of 23 chromosomes and a zygote with 47 chromosomes. Trisomy 21 or Down's syndrome, Trisomy 18 or Edward Syndrome, and Trisomy 13 or Patau Syndrome are the three primary syndromes associated with autosomy trisomy. Trisomy 8, trisomy 9, and trisomy 2 are all rare trisomies. Trisomy 21 is the most prevalent chromosomal anomaly among live births (1 in 730 live births) and the most common kind of intellectual disability caused by chromosomal aberrations that can be seen under a microscope. Trisomy 21 or the presence of the distal part of the long arm of chromosome 21 are the genetic causes of this syndrome. Free trisomy 21, Robertsonian translocations, mosaicism, duplication of the DS crucial area, and other structural rearrangements involving chromosome 21 are all part of the cytogenetic profile of down syndrome. Edward syndrome is the second most frequent autosomal trisomy in live births, with prevalence estimates ranging from 1/3600 to 1/10,000, with 1 in 6,000 being the best overall estimate. The phenotype of trisomy 18 (Edwards syndrome) is caused by full, mosaic, or partial trisomy 18q. The most prevalent form (about 94 percent of cases) is complete or full trisomy 18, in which each cell contains three complete copies of chromosome 18. The third most prevalent autosomal trisomy in live births is Trisomy 13 (Patau Syndrome). Patau syndrome is one of three forms of trisomy disorders, with a frequency of one in every 12000 live births. The most prevalent kind is full trisomy 13. This type has three full copies of chromosome 13 on its chromosomes. People with partial trisomy 13 have two full copies of chromosome 13 plus an additional section of chromosome 13. Mosaic trisomy 13 is a condition in which some of the body's cells contain three copies of chromosome 13 while others have only two.

We want to provide you a quick rundown of the above-mentioned autosomal trisomy disorders, including their incidence, chromosomal abnormalities, clinical aspects, and treatment options.

Author(S) Details

Priyanka Pandey
Department of Anatomy, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India.

Rakesh Kumar Verma
Department of Anatomy, King George’s Medical University, Lucknow, India.

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