Genetics Flashcards
What are the problems associated with down syndrome?
Heart defects, intestinal abnormalities, hearing loss, vision problems, infections, and memory loss
amniocentesis
removal and examination of a small sample of amniotic fluid that surrounds the fetus, usually done 15-20 weeks, highly accurate in diagnosing and ruling out down syndrome
Klinefelter syndrome
results in an extra X chromosome to make XXY. even those these individuals are male their masculinization is incomplete.
turner syndrome
result is an offspring with 22 pairs of autosomes and a single unmatched x chromosome (XO). This embryo is more likely to be spontaneously aborted. Characterized by short and wide chests and a prominent fold of skin on their necks. They are sterile, have low levels of estrogen, and small breasts. Mental retardation is not associated with this disorder.
Mendelian
phenotypes due to alterations at a single gene
Dominant traits
require only one copy of a factor to be expressed
What is the inheritance pattern of an autosomal recessive inheritance?
inheritance is usually from both parents, each of whom is a heterozygote (carrier) and each of whom is usually clinically unaffected by his or her carrier status.
mitochondrial inheritance
transmission of mitochondrial DNA is maternal. Mother will pass he mitochondrial DNA including mutant DNA to all of her children. Affected males do not pass on the gene.
karyotyping
human cells are grown in a culture, chromosomes are sorted and arranged into pairs, sex chromosomes are placed in lower right hand corner, use hybridization with fluorescent DNA
What is a newborn tested for when testing for cystic fibrosis?
increased levels of immunoreactive trypsinogen (IRT) a pancreatic protein linked to cystic fibrosis
What does the mesoderm give rise to during development?
body tissues, such a muscle, cartilage, bone, and dermis, blood vessels, reproductive organs, blood, enamel of the teeth
When is the critical period for teratogenesis?
during week 3-16, this is when many organs are formed
What are some types of pharmacological teratogens?
thalidomide, diethylstilbestrol, retinoic acid
What are some types of infectious agent teratogens?
toxoplasma gondii, rubella, cytomegalovirus, herpes, congenital syphilis
What are some types of industrial agent teratogens?
lead, mercury, pesticides
What are some recreational teratogens?
alcohol, tobacco, cocaine
Thalidomide
A very teratogenic drug! In the 1950s it was given to women to treat morning sickness. Causes Amelia which is complete absence of a limb or limbs. Meromelia which is only partial absence of a limb. Phocomelia which is absence of the longs bones of the legs or arms.
Diethylstilbestrol (DES)
Estrogen that was used to prevent spontaneous abortion. Some studies show an increase in risk of breast cancer. Of DES daughters some developed vaginal clear-cell adenocarcinoma. Structural defects in cervix, uterus, and fallopian tubes. There was a decrease in fertility.
How does taking excessive vitamin A during pregnancy affect offspring?
Cleft lip, cleft palate, cardiac defects, and hydrocephalus is the most common central nervous system defect
What are the effects of taking ACE inhibitors during pregnancy?
During 2nd and 3rd trimester there is renal dysfunction, growth retardation, fetal demise, oligohydraminos. During 1st trimester there can possibly be cardiac defects and central nervous system defects.
What are some medication names for anticonvulsants?
Valproic acid, Carbamazepine, Phenytoin
What are the effects of taking NSAIDs during pregnancy?
During 1st trimester there can be cardiac ventricular and septal defects. During 3rd trimester the results are a baby with pulmonary hypertension.
What are the characteristics features of a offspring with fetal alcohol syndrome?
behavior disturbances, brain defects, cardiac defects, spinal defects, craniofacial anomalies, absent or hypoplastic philtrum, broad upper lips, flattened nasal bridge, hypoplastic upper lip vermilion, micrognathia, short nose, short palpebral tissues
What are some manifestations of congenital syphilis in a newborn?
nasal discharge white to bloody, hepatomegaly, rash, CNS involvement are seizures and hydrocephalus, long bone abnormalities
amyloid plaques
abnormal deposits of a protein called beta amyloid that is found in the space between neurons, this change occurs with Alzheimer’s disease
amyloid precursor protein
chromosome 21, gene associated with early on-set of Alzheimer’s disease
presenilin 1
chromosome 14, associated with early-onset AD, abnormalities in the gene lead to an overproduction of more toxic beta-amyloid peptide proteins
presenilin 2
chromosome 1, associated with early on-set AD but is rare, perhaps causes and increases apoptosis in neurodegeneration
apolipoprotein E
most identified gene involved in late on-set Alzheimer’s disease, found on chromosome 19, APOE epsilon 4 appears to increase risk for AD, this is susceptibility gene not a determinant gene, not everyone with this will get AD
