Edward s Syndrome (Trisomy 18)- Autopsy Report of a Rare Case
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Date
2020-09
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Akshantala Enterprises Private Limited
Abstract
Edward’s syndrome is a genetic disorder characterized by Trisomy 18. Incidence of Edward syndrome is reported to be around 1 in 3500 to 7000. It is known to be second most common Trisomy after Down’s syndrome (Trisomy 21). It is noted to be more common in girls than in boys in ratio 3:1. But here we report the autopsy report of male foetus. Trisomy 18 has multisystem involvement. Cardiovascular system is most commonly involved, followed by extremities, Urinary system, Head and Neck, Gastrointestinal tract and genitals. There are 3 types of Trisomy 18- Full, Partial and Mosaic type. The most common type is Full Trisomy 18, accounting for about 95% of cases. In Full Trisomy 18, every cell of the body has extra chromosome 18. Both Partial and Mosaic type of Trisomy 18 are very rare, In Partial Trisomy 18, each cell has two copies of chromosome 18 plus a segment of extra material from chromosome 18. In Mosaic Trisomy 18, the extra chromosome is present in some of the cells of the body.1In our case we have used Quantitative fluorescent polymerase chain reaction (QF-PCR) to detect Trisomy 18. It has entered the field of prenatal diagnosis to overcome the need to culture foetal cells, hence to allow rapid diagnosis of some selected chromosomal anomalies like aneuploidy in chromosomes 13, 18, 21, X and Y. QF-PCR is feasible on fewer cells, and since the analysis can easily be automated, many samples can be processed at the same time and the whole process taking around 30 min. QF-PCR is based on the amplification of chromosome-specific DNA sequences (STR, short tandem repeats) polymorphic in length between subjects. By means of fluorescent primers, the amplified segments can be visualized and quantified as peakareas on automated DNA scanners. Normal heterozygous subjects are expected to show two peak areas (peaks ratio 1:1) for each chromosome analysed, while trisomies are visualized either as an extra peak (triallelic subjects) or as a 2:1 ratio peak between the two areas.2,3
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Reddy Chaitra Dasa, Vasireddy Guvera, Induri Sreelakshmi, Nithyananda Bhavani Shankara, Durga Kharidehal. Edward s Syndrome (Trisomy 18)- Autopsy Report of a Rare Case. Journal of Evolution of Medical and Dental Sciences. 2020 Sep; 9(38): 2843-2846