Genetic Etiology of Chromosome 21 Nondisjunction and Down syndrome Birth: Aberrant Recombination and Beyond

Ghosh, Sujay; Ghosh, Prasenjit

doi:10.4172/2472-1115.1000102

Cited by 3 publications

(3 citation statements)

References 34 publications

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“…Pembelahan meiosis II akan dimulai kembali ketika fertilisasi oleh sel sperma. Fase jeda tersebut yang dapat meningkatkan resiko terjadinya non disjungsi pada pembelahan meiosis (Ghosh & Ghosh, 2015).…”

Section: ) Kelainan Genetik Yang Sering Terjadi Adalah Kelainan Pada ...unclassified

Analisis Studi Kasus Mengenai Usia Ibu dan Gambaran Fisik Penderita Sindrom Down

Arvanda,

Izzah

2023

BIOSENSE

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Down syndrome or trisomy 21 is the most common genetic disorder among other genetic disorders. The definition of Down syndrome is a chromosomal abnormality in which there is an extra copy of chromosome 21 due to non-disjunction, mosaicism or the rarest occurrence is translocation. The age of the mother when pregnant is one of the factors causing Down syndrome, the older the mother's age, the greater the chance of Down syndrome. The development of Down syndrome children is different from other normal children, so special care and parenting are needed. The purpose of this research is to analyze through case studies of Down syndrome patients aspects of birth occurrence, aspects of child growth and development, and aspects of the physical description of Down syndrome patients. The results of this study indicate that many factors can influence the occurrence of Down syndrome, namely genetic factors, radiation factors, and the age of the mother. If Down syndrome children receive a form of therapy, health care, and supportive parenting and environment. Then Down syndrome children can adapt well such as how to communicate and interact.

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Section: ) Kelainan Genetik Yang Sering Terjadi Adalah Kelainan Pada ...unclassified

Analisis Studi Kasus Mengenai Usia Ibu dan Gambaran Fisik Penderita Sindrom Down

Arvanda,

Izzah

2023

BIOSENSE

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“…Fuches and his colleagues in 1960 determined gender to rule out sex linked recessive diseases; hemophilia from amniotic fluid [3]. Advancements in the field of prenatal diagnosis starting from intrauterine detection of genetic defects [4] and first prenatal diagnosis of Down's Syndrome [5] to preimplantation genetic diagnosis [6] a broad spectrum of prenatal genetic tests have facilitated the parents about the wellbeing of their unborn child.…”

Section: Introductionmentioning

confidence: 99%

Cell Free Fetal DNA As Biomarker for Pregnancy Loss Disorders

Tahir

2022

AJBSR

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Cell free fetal DNA (cff DNA) is apoptotic fetal DNA that is shed from placenta and flows in maternal blood. This can be used as an indicative biomarker to rule out pregnancy associated complications. The objective of this study is to investigate the correlation of the concentration of cff DNA with intrauterine deaths. The RHD gene (Rh blood group, D antigen) was used as fetal DNA marker for the confirmation of fetal DNA and GAPDH gene (Glyceraldehyde-3-phosphate dehydrogenase) was used as internal control. The control group comprises of 54 healthy singleton pregnant women without any history of pregnancy associated complications or fetal chromosomal abnormalities. The control group was confirmed by follow up for the delivery of normal baby.Case group consisted of pregnant women who were showing abnormal gynecological findings/history of pervious miscarriages or chromosomal abnormalities. Intrauterine death (IUDs) was confirmed after following up the pregnancy. T-test was applied to find out the correlation between control and case groups. We have observed significantly higher quantities of cell free fetal DNA in case group as compared to control group (P value <0.0001, r2=0.4266). The case group was further subdivided into five groups depending upon the reason of intrauterine death of fetus. A significant correlation has been observed among all the five case subgroups as compared to control group (P value <0.0001). Our study concludes there is a significant increase in the concentration of cell free fetal DNA of IUD cases before onset of the conditions.

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“…In search of risk factors associated with DS birth, researchers initially identified advanced maternal age at conception as a major challenge to healthy oocyte maturation and correct chromosome segregation [ 4 ]. Later, the recombination anomaly on Ch21q was characterized as the first molecular correlate that predisposes homologue pairs to segregate erroneously during meiosis [ 5 ]. In characterizing the interactions between maternal age and anomalous recombination patterns on Ch21q in NDJ, two independent studies on US [ 2 ], and, Indian [ 6 ] DS samples revealed that the absence of recombination as well as a single exchange within the telomeric region of 21q are maternal age-independent risk factors for Ch21 MI NDJ.…”

Section: Introductionmentioning

confidence: 99%

The etiology of Down syndrome: Maternal MCM9 polymorphisms increase risk of reduced recombination and nondisjunction of chromosome 21 during meiosis I within oocyte

et al. 2021

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Altered patterns of recombination on 21q have long been associated withthe nondisjunction chromosome21within oocytes and the increased risk of having a child with Down syndrome. Unfortunately the genetic etiology of these altered patterns of recombination have yet to be elucidated. We for the first time genotyped the gene MCM9, a candidate gene for recombination regulation and DNA repair in mothers with or without children with Down syndrome. In our approach, we identified the location of recombination on the maternal chromosome 21 using short tandem repeat markers, then stratified our population by the origin of meiotic error and age at conception. We observed that twenty-five out of forty-one single nucleotide polymorphic sites within MCM9 exhibited an association with meiosis I error (N = 700), but not with meiosis II error (N = 125). This association was maternal age-independent. Several variants exhibited aprotective association with MI error, some were neutral. Maternal age stratified characterization of cases revealed that MCM9 risk variants were associated with an increased chance of reduced recombination on 21q within oocytes. The spatial distribution of single observed recombination events revealed no significant change in the location of recombination among women harbouring MCM9 risk, protective, or neutral variant. Additionally, we identified a total of six novel polymorphic variants and two novel alleles that were either risk imparting or protective against meiosis I nondisjunction. In silico analyses using five different programs suggest the risk variants either cause a change in protein function or may alter the splicing pattern of transcripts and disrupt the proportion of different isoforms of MCM9 products within oocytes. These observations bring us a significant step closer to understanding the molecular basis of recombination errors in chromosome 21 nondisjunction within oocytes that leads to birth of child with Down syndrome.

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Genetic Etiology of Chromosome 21 Nondisjunction and Down syndrome Birth: Aberrant Recombination and Beyond

Cited by 3 publications

References 34 publications

Analisis Studi Kasus Mengenai Usia Ibu dan Gambaran Fisik Penderita Sindrom Down

Analisis Studi Kasus Mengenai Usia Ibu dan Gambaran Fisik Penderita Sindrom Down

Cell Free Fetal DNA As Biomarker for Pregnancy Loss Disorders

The etiology of Down syndrome: Maternal MCM9 polymorphisms increase risk of reduced recombination and nondisjunction of chromosome 21 during meiosis I within oocyte

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