chromosomal abnormalities
What is meant by aneuploidy?
When there is an extra chromosome or not enough chromosomes (wrong # of chromosomes).
what is a dominant trait?
what is a recessive trait?
expressed when a single allele is present.
expressed when both alleles are present.
What is karyotyping?
When the chromosomes are directly examined and a determination is made on whether the chromosomes are normal. It is used to examine the number and structure of chromosomes in a cell to detect abnormalities, such as missing, extra, or rearranged chromosomes.
What malignant tumors occur most commonly in children?
retinoblastoma, neuroblastoma, wilms tumor, lymphoma, acute leukemia, Rhabdomyosarcoma
1. agenesis
2. hypoplasia
1. absence of an organ or structure because it didn't develop. (ex: Renal Agenesis- no kidney)
2. An organ that is underdeveloped or smaller than normal. (ex. Pulmonary hypoplasia- lungs are underdeveloped)
What type of chromosomal abnormality is associated with Down Syndrome?
Down syndrome is associated with a chromosomal abnormality known as trisomy 21, where there are three copies of chromosome 21 instead of the usual two. This extra chromosome leads to various physical features such as epicanthal folds, Brushfield spots, a short nose, clinodactyly, a large tongue, and often a pronounced heart murmur.
dominant inheritance pattern
A dominant trait will appear if a person inherits the gene from just one parent, whether they have one dominant allele (heterozygous) or two (homozygous dominant). If one parent is heterozygous and the other is homozygous recessive, there is a 50% chance their child will inherit the dominant trait.
What is amniocentesis?
Invasive test that predicts if a woman is carrying a baby with a chromosomal abnormality. A needle is inserted into the mothers belly. And material such as a small amount of amniotic fluid, which contains fetal cells, is removed from the womb to check for genetic disorders or birth defects.
What causes respiratory distress syndrome?
it takes place when a baby is born before 34 weeks of pregnancy. Is caused by immaturity of type II pneumocytes, leading to inadequate surfactant production (surfactant allows the lungs to function properly). Hyaline membrane disease is a breathing problem in premature infants caused by a lack of surfactant
1. Dysraphic anomalies
2. Spina bifida
1. Problems where parts of the body do not fuse properly during development. (ex. Meningocele: Meninges bulge through a spine gap without spinal cord involvement.)
2. A condition where the spinal cord doesn't fully close, leading to spinal defects.
What types of abnormalities are associated with the X chromosome?
turner syndrome, jacobs syndrome, triple x syndrome, complete androgen insensitivity syndrome, klinefelter syndrome
recessive inheritance pattern
Only way that the recessive trait can be transmitted to the offspring is if both parents are carriers. A trait that only shows up if you get the same gene from both parents.
What is chorionic villus sampling?
A prenatal test where a small sample of cells is taken from the chorionic villi (tiny projections of the placenta) to test for genetic and chromosomal conditions in the fetus. It is a more dangerous test but can be done earlier in pregnancy (8-10 weeks) that gives quicker results.
What happens if respiratory distress syndrome does not resolve?
If it doesn't resolve the baby can die of respiratory failure or it can lead to chronic lung disease (like bronchopulmonary dysplasia) and long-term oxygen dependence. Persistent low oxygen levels can damage vital organs such as the brain, heart, and kidneys.
1. Involutional failures
2. Persistent thyroglossal duct
1. When a structure that should shrink or disappear during development doesn't. (apoptosis allows it to disappear but there are occasions where it fails)
2.When a part of the thyroid development doesn't close, leading to cysts in the neck.
1. what is turner syndrome
2. what is triple x syndrome
1. Females with only one X chromosome and are missing the second chromosome. Results in short stature, infertility, heart defects, and no puberty development.
2. Females with an extra X chromosome, usually with mild symptoms such as learning difficulties or infertility.
What are polygenic disorders?
Conditions controlled by multiple genes, not just one. Traits like skin color, hair color, eye color, and height are influenced by multiple genes working together.
What are the different types of errors in morphogenesis?
Agenesis, Hypoplasia, Dysraphic anomalies, Spina bifida, Involutional failures, Persistent, thyroglossal duct, Divisional failures, Syndactyly, Atresia, Ectopia or heterotopia
What causes neonatal jaundice?
Occurs when the baby’s liver is immature and cannot process bilirubin quickly enough therefore there is a buildup of bilirubin in the blood. It can also be caused by factors like infections, blood type incompatibility, or prematurity.
1. Divisional failures
2.Syndactyly
1.When cells or tissues fail to divide or separate properly, causing abnormalities.
2. When fingers or toes are fused together due to incomplete separation. (webbing)
**Failure of apoptosis during embryonic and fetal development could lead to syndactyly**
1. klinefelter syndrome
2. jacobs syndrome
3. Complete Androgen Insensitivity Syndrome
1. Males with an extra X chromosome, leading to tall stature, reduced testosterone, infertility, and possible mild cognitive impairment.
2. Males with an extra Y chromosome, often resulting in taller stature and possible learning difficulties or behavioral issues.
3. Males with a mutation in the androgen receptor, causing them to develop as females despite having male (XY) chromosomes.
How does interaction among genes affect the expression of genetic traits (phenotypes)?
Through epistasis and modifier genes where one gene masks or modifies the effect of another.
What is a hamartoma?
An overgrowth of normal cells or tissues that are part of that organ but are found in the wrong location. (ex- pulmonary hamartoma- a growth of cartilage in the middle of the lungs).
1. Retinoblastoma:
2. Neuroblastoma:
3. Wilms tumor:
4. Lymphoma:
5. Acute leukemia:
6. Rhabdomyosarcoma:
1.A cancer of the eye.
2. A cancer that starts in nerve tissue, in adrenal glands or along the spine.
3. A type of kidney cancer.
4. Cancers of the lymphatic system.
5. A fast-growing cancer of the blood and bone marrow.
6. A cancer of the soft tissues, especially muscles.
1. Atresia
2. Ectopia or heterotopia
1.When a structure that was formally there regresses. (ex. esophageal atresia- the esophagus was there but then it shrank).
2.When an organ or tissue develops in the wrong location. (ex. A piece of pancreas grows in the intestine)