Genetics and Genomics Flashcards
ATI
Autosomal choromosomes
22 pairs
One chromosome from each parent makes up each pair of autosomal chromosomes
Multifactorial disorders
Multifactorial disorders are affected by more than one gene as well as how they interact with the environment and lifestyle.
Aneuploidy
-An imbalanced chromosomal complement caused by one or more extra or missing chromosomes.
-most common chromosome deviation in humans and the main genetic contributor to birth anomalies and spontaneous abortions.
Characteristics of Down syndrome (physical)
Flat facial appearance, specifically the nose
Eyes wide set with upward slant
Shorter neck
Smaller ears
Protruding tongue
Smaller hands and feet
Single palmar crease
Weak muscles due to poor tone
Sex chromosomal anomalies types
single-gene disorders, chromosome anomalies, and multifactorial inheritance
When caring for a newborn who has Down syndrome, what characteristics or disorders place the newborn at risk for aspiration?
A protruding tongue can make feedings difficult and may affect digestion. Poor muscle tone or weak muscles can make feeding a challenge and limit the newborn’s ability to suck and swallow successfully. Heart defects can contribute to poor feeding on any newborn, placing the newborn at risk for aspiration. Therefore, a newborn who has both Down syndrome and a congenital heart defect has a higher risk for feeding difficulties and aspiration.
Common Down syndrome congenital issues
Duplication Mutation
A kind of mutation in which a DNA segment, ranging in size from a few bases to a major chromosomal region, is produced in one or more copies.
Ring chromosome mutation
A circular structure that results from a chromosome’s broken ends fusing together after it breaks in two.
Isochromosome mutations
A structural anomaly in which the chromosome arms are mirror reflections of one other.
deletion mutation
A kind of mutation in which a DNA segment loses one or more nucleotides.
translocation mutation
Happens when a chromosome splits and the two broken pieces reattach to separate chromosomes.
inversion mutation
Occur when a segment splits off and rejoins the same chromosome in the opposite direction.
Sex chromosome anomalies
affect 1 in 400 births and are the most prevalent chromosomal disorders.
Turner Syndrome
Female
Short stature
Wide chest
Low hair line
Early loss of ovarian function
Lymphedema
Amenorrhea
Structural kidney defects
Structural heart defects
Klinefelter syndrome
Male
Increased height
Long extremities
Female hair distribution
Small testes
Infertility
Delayed puberty
Developmental delay
Increased risk for breast cancer
Triple X syndrome
Female
Increased height
Potential learning disability
Delayed speech and language skills
Weak muscle tone
Behavioral and emotional difficulties
Seizures
Kidney abnormalities
XYY syndrome
Male
Increased height
Potential learning disabilities
Delayed speech and language skills
Weak muscle tone
Hand tremors
Asthma
Seizures
Scoliosis
Behavioral and emotional difficulties
Autosomal Dominant mutation
Huntington’s disease and Marfan syndrome.
Autosomal Recessive mutations
Typically, autosomal recessive disorders do not affect every generation of a family. Cystic fibrosis, sickle cell disease, and phenylketonuria are examples of autosomal recessive conditions.
Inborn Errors: Phenylketonuria
a rare hereditary condition that causes the body to accumulate phenylalanine, an amino acid. PKU is caused by changes in the phenylalanine hydroxylase (PAH) gene. This gene contributes to the synthesis of the enzyme necessary to break down phenylalanine.
Phenylalanine accumulates and is harmful to the brain when PAH is absent or inadequate. Most clients who have PKU would become severely intellectually disabled without therapy. Treatment involves a carefully monitored, phenylalanine-restricted diet starting in the first few days or weeks of birth to prevent intellectual impairment.
X-Linked Dominant mutation
fragile X syndrome.
seen less in males
X-Linked Recessive mutation
Fathers are unable to pass on X-linked traits to their male offspring, just like in the case of X-linked dominant conditions. Hemophilia is an illustration of an X-linked recessive illness.
Targeted Carrier screening
Screening for diseases based on ethnicity or family history.
expanded carrier screening
A single sample is used to screen for numerous disorders without race or ethnicity as a factor.
