Edwards syndrome, or trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18, is a genetic syndrome caused by the presence of an extra chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 18. The extra chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics is either from 3 full copies of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 18 or an additional segment of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 18. As the 2nd most common trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations, Edwards syndrome is seen in 1 out of every 5,500 live births and increases with maternal age. Many cases are detected prenatally with maternal screening Screening Preoperative Care and ultrasound findings. Abnormalities include intrauterine growth restriction (IUGR), overlapping fingers, typical craniofacial features, rocker-bottom feet, and congenital Congenital Chorioretinitis heart defects. Trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18 frequently results in fetal loss. For term pregnancies, most deaths occur during the 1st 6 months of life. Delivery in a specialized center is recommended for full-term pregnancies and intervention is based on associated abnormalities.
Last updated: 25 Jan, 2022
Edwards syndrome, or trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18, is defined as the presence of 3 copies of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 18.
Mnemonic for Edwards syndrome (trisomy 18): “At 18 you can vote in an election.”
Meiosis Meiosis The creation of eukaryotic gametes involves a DNA replication phase followed by 2 cellular division stages: meiosis I and meiosis II. Meiosis I separates homologous chromosomes into separate cells (1n, 2c), while meiosis II separates sister chromatids into gametes (1n, 1c). Meiosis I is a separation of replicated sister chromatids.
Image by Lecturio.Meiosis Meiosis The creation of eukaryotic gametes involves a DNA replication phase followed by 2 cellular division stages: meiosis I and meiosis II. Meiosis I separates homologous chromosomes into separate cells (1n, 2c), while meiosis II separates sister chromatids into gametes (1n, 1c). Meiosis II is a separation of sister chromatids, producing 4 haploid Haploid The chromosomal constitution of cells, in which each type of chromosome is represented once. Symbol: n. Basic Terms of Genetics cells/gametes.
Image by Lecturio.Chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics reduction is necessary so the zygote Zygote The fertilized ovum resulting from the fusion of a male and a female gamete. Fertilization and First Week is diploid Diploid The chromosomal constitution of cells, in which each type of chromosome is represented twice. Symbol: 2n or 2x. Basic Terms of Genetics in fertilization Fertilization To undergo fertilization, the sperm enters the uterus, travels towards the ampulla of the fallopian tube, and encounters the oocyte. The zona pellucida (the outer layer of the oocyte) deteriorates along with the zygote, which travels towards the uterus and eventually forms a blastocyst, allowing for implantation to occur. Fertilization and First Week.
Image by Lecturio.
Nondisjunction
Nondisjunction
The failure of homologous chromosomes or chromatids to segregate during mitosis or meiosis with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none.
Basic Terms of Genetics:
The failure to properly separate 2
homologous chromosomes
Homologous chromosomes
Basic Terms of Genetics or sister chromatids during
cell division
Cell Division
A type of cell nucleus division by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes of the somatic cells of the species.
Cell Cycle.
Nondisjunction
Nondisjunction
The failure of homologous chromosomes or chromatids to segregate during mitosis or meiosis with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none.
Basic Terms of Genetics results in aneuploidy (a state of chromosomal imbalance).
A diagram illustrating the etiological mechanism of
nondisjunction
Nondisjunction
The failure of homologous chromosomes or chromatids to segregate during mitosis or meiosis with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none.
Basic Terms of Genetics in
trisomy
Trisomy
The possession of a third chromosome of any one type in an otherwise diploid cell.
Types of Mutations:
An egg carrying 2 copies of the same
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics acquires another when fertilized, resulting in 3 copies.
Unbalanced translocation:
Extra
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics 18 material (long
arm
Arm
The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior).
Arm: Anatomy) attached to
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics 15 (on the left) and
partial
trisomy
Trisomy
The possession of a third chromosome of any one type in an otherwise diploid cell.
Types of Mutations 18 from 2 sets of
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics 18 + extra long
arm
Arm
The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior).
Arm: Anatomy
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics 18 (on the right)
Boy with
trisomy
Trisomy
The possession of a third chromosome of any one type in an otherwise diploid cell.
Types of Mutations 18 in early infancy and at 1 year of age:
Note the characteristic
hand
Hand
The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves.
Hand: Anatomy feature of overriding fingers and
tracheostomy
Tracheostomy
Surgical formation of an opening into the trachea through the neck, or the opening so created.
Laryngomalacia and Tracheomalacia in place.
Infant with trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18 and overlapping fingers
Image: “ Congenital Congenital Chorioretinitis hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage in an Egyptian baby with trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18: a case report” by Metwalley KA, Farghalley HS HS Hypertrophic scars and keloids are raised, red, and rigid (3 rs) scars that develop during cutaneous wound healing and are characterized by a local abnormal proliferation of fibroblasts with over-production of collagen. Over-expression of growth factors and decreased production of molecules that promote matrix breakdown appear to be involved in the etiology. Hypertrophic and Keloid Scars, Abd-Elsayed AA AA Amyloidosis. License: CC BY 2.0Infant with trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18 and rocker-bottom feet (a common finding)
Image: “ Congenital Congenital Chorioretinitis hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage in an Egyptian baby with trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18: a case report” by Metwalley KA, Farghalley HS HS Hypertrophic scars and keloids are raised, red, and rigid (3 rs) scars that develop during cutaneous wound healing and are characterized by a local abnormal proliferation of fibroblasts with over-production of collagen. Over-expression of growth factors and decreased production of molecules that promote matrix breakdown appear to be involved in the etiology. Hypertrophic and Keloid Scars, Abd-Elsayed AA AA Amyloidosis. License: CC BY 2.01st trimester | 2nd trimester | ||||||
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NT | PAPP-A | hCG | AFP AFP The first alpha-globulins to appear in mammalian sera during fetal development and the dominant serum proteins in early embryonic life. Hepatocellular Carcinoma (HCC) and Liver Metastases | Estriol Estriol A hydroxylated metabolite of estradiol or estrogen that has a hydroxyl group at C3, 16-alpha, and 17-beta position. Estriol is a major urinary estrogen. During pregnancy, a large amount of estriol is produced by the placenta. Isomers with inversion of the hydroxyl group or groups are called epiestriol. Noncontraceptive Estrogen and Progestins | hCG | Inhibin A Inhibin A Glycoproteins that inhibit pituitary follicle stimulating hormone secretion. Inhibins are secreted by the sertoli cells of the testes, the granulosa cells of the ovarian follicles, the placenta, and other tissues. Inhibins and activins are modulators of follicle stimulating hormone secretions; both groups belong to the TGF-beta superfamily, as the transforming growth factor beta. Inhibins consist of a disulfide-linked heterodimer with a unique alpha linked to either a beta a or a beta B subunit to form inhibin a or inhibin b, respectively. Menstrual Cycle | |
Trisomy 13 Trisomy 13 Trisomy 13, or Patau syndrome, is a genetic syndrome caused by the presence of 3 copies of chromosome 13. As the 3rd most common trisomy, Patau syndrome has an incidence of 1 in 10,000 live births. Most cases of Patau syndrome are diagnosed prenatally by maternal screening and ultrasound. More than half of the pregnancies result in spontaneous abortions. Patau Syndrome (Trisomy 13) | ↑ | ↓↓ | ↓ | Unchanged | Unchanged | Unchanged | Unchanged |
Trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18 | ↑↑ | ↓↓ | ↓↓ | ↓ | ↓↓ | ↓↓ | Unchanged |
Trisomy 21 Trisomy 21 Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems. Down syndrome (Trisomy 21) | ↑↑ | ↓↓ | ↑ | ↓ | ↓ | ↑ | ↑ |
Karyotype
Karyotype
The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere.
Congenital Malformations of the Female Reproductive System showing
trisomy
Trisomy
The possession of a third chromosome of any one type in an otherwise diploid cell.
Types of Mutations of the 18th
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics
(notice the pairs of
chromosomes
Chromosomes
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
DNA Types and Structure 16 and 17 and the extra 18th
chromosome
Chromosome
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
Basic Terms of Genetics)