Search results
Results from the WOW.Com Content Network
The following is a list of genetic disorders and if known, type of mutation and for the chromosome involved. Although the parlance "disease-causing gene" is common, it is the occurrence of an abnormality in the parents that causes the impairment to develop within the child. There are over 6,000 known genetic disorders in humans.
A chromosomal abnormality, chromosomal anomaly, chromosomal aberration, chromosomal mutation, or chromosomal disorder is a missing, extra, or irregular portion of chromosomal DNA. [ 1 ] [ 2 ] These can occur in the form of numerical abnormalities, where there is an atypical number of chromosomes, or as structural abnormalities, where one or ...
A chromosomal disorder is a missing, extra, or irregular portion of chromosomal DNA. [33] It can be from an atypical number of chromosomes or a structural abnormality in one or more chromosomes. An example of these disorders is Trisomy 21 (the most common form of Down syndrome), in which there is an extra copy of chromosome 21 in all cells. [34]
The smallest single base deletion mutations occur by a single base flipping in the template DNA, followed by template DNA strand slippage, within the DNA polymerase active site. [3] [4] [5] Deletions can be caused by errors in chromosomal crossover during meiosis, which causes several serious genetic diseases.
Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. [4] Risk factors include folate deficiency , drinking alcohol or smoking during pregnancy, poorly controlled diabetes , and a mother over the age of 35 years old.
Prader–Willi (PWS) and Angelman syndrome (AS) are distinct neurogenetic disorders caused by chromosomal deletions, uniparental disomy or loss of the imprinted gene expression in the 15q11-q13 region. Whether an individual exhibits PWS or AS depends on if there is a lack of the paternally expressed gene to contribute to the region.
Sex chromosome anomalies belong to a group of genetic conditions that are caused or affected by the loss, damage or addition of one or both sex chromosomes (also called gonosomes). In humans this may refer to: 45, X, also known as Turner syndrome; 45,X/46,XY mosaicism, also known as X0/XY mosaicism and mixed gonadal dysgenesis; 46, XX/XY
Chromosome instability syndromes include several inherited neurodegenerative diseases that are due to mutations in genes that encode enzymes necessary for DNA repair. Epigenetic alterations often occur in association with the DNA repair defect, and such alterations likely have a role in the etiology of the disease. Chromosome instability ...