Lecture 11 - Developmental and Genetic diseases Flashcards
the etiology of a disease can be…..
environmental
genetic
polygenic (combo of both)
TRUE OR FALSE
genetic diseases are common
true
50% of miscarriages during early gestation have demonstrable genetic abnormality
hereditary disease vs familial disease
hereditary is derived from parents
familial is transmitted from one generation to another
genotype vs phenotype
genotype = genetic composition
phenotype = observed functional and morphological characteristics caused by genotype
gene vs allele
gene is composed of 2 alleles. part of DNA sequence that codes for specific trait
allele is pair of genes on a particular chromosome at a particular place that controls the same characteristics like blood type
genetic disorders can be characterized into what 4 categories
monogenic (mendelian)
multifactorial
chromosomal aberrations
mitochondrial disorders
what is a monogenic (mendelian) disease
genetic disorder
mutation that affects ONE GENE that results in new change in fucntion/morphology
what are multifactorial disorders
genetic disorder
due to polygenic factors – multiple genes or more than 1 environmental factor
what are chromosomal aberrations
genetic disorder
abnormal number or structure of chromosomes
what are mitochondrial disorders
genetic disordered
inherited from maternal side - very rare
if a child has 1 affected parent and the pattern is autosomal dominant, what are the odds that the children will have the disease?
50-50
true or false
males and females are equally affected by a trait that is autosomal dominant
true
the phenotype expression of an autosomal dominant trait occurs with…..
a SINGLE COPY of a defective allele
name 4 disorders that are autosomal dominant
achondroplasia
familial hypercholesterolemia
Huntington Disease
Neurofibromatosis Type 1
true or false
achondroplasia has an autosomal recessive pattern
FALSE - autosomal dominant
explain the morphological changes that occur in achondroplasia
shortened limbs (rhizomelia) with short hands and stubby fingers, notmal lenght torso
_____ is the most common cause of dwarfism
achondroplasia
AUTOSOMAL DOMINANT
Achondroplasia is caused by a mutation in what gene?
fibroblast growth factor receptor 3 gene
(FGFR3)
the risk of a new mutation in the FGRF3 gene increases with…..
what disorder is this?
the age of the father
achondroplasia
what are treatments for achondroplasia
support groups, growth hormon therapy
________ is characterized by xanthomas
familial hypercholesterolemia (autosomal dominant)
xanthomas = cholesterol deposits in skin, tendons
name 2 mutations that can result in familial hypercholesterolemia
LDLR gene - encodes LDL receptor protein which normally removes
apolipoprotein B (ApoB) - part of the LDL that binds to receptor
heterozygous of LDLR gene may cause….
hmozygous of the LDLR gene may cause….
heterozygous may cause premature cardiovascular disease
homozygous may cause severe cardiovascular disease in childhood
what is familial hypercholesterolemia treated with
statins
bile acid sequestrants
other lipid lowering agents
explain Huntington Disease
affects basal ganglia of the brain - AUTOSOMAL DOMINANT
muscle spasms, amnesia, delusion, compulsive behavior, delirium, depression, anxiety, memory loss, tremors
NO CURE
name 4 autosomal recessive disorders
cystic fibrosis
sickle cell disease
Tay-Sachs Disease
PKU (phenylketonuria)
the phenotype expression of an autosomal recessive trait requires _____ cop(ies) of the defective allele
what about for autosomal dominant?
autosomal recessive = 2 copies
autosomal dominant = only 1 copy
cystic fibrosis is involved with a defective……
CFTR (cystic fibrosis transmembrane conductance regulator)
whether it’s defective chloride secretion, not synthesizing the regulator at all, defective ATP binding to it, etc
autosomal _______ skips a generation
recessive
if someone has carrier parents ,what are the odds of them getting the disease for an autosomal recessive trait
25%
what increases the risk for inheriting an autosomal recessive disease
cosanguinity (within family relations
clinical manifestations of cystic fibrosis
copd - due to excess mucus production
pancreatic insufficiency
salivary gland obstruction
gall bladder stones
meconium ileus (bb first stool is blocking the ileum)
manifestation of PKU (phenylketonuria)
musty odor in breath, skin, urine
skin rashes
lighter skin and hair color
small head
intellectually disabled
mental health
hyperactice
what is the exact cause of PKU
phenylalanine can’t transform into melanin. thus, ppl need to follow diet that LIMITS phenylalanine
autosomal recessive
sickle cell disease involves an infarction of what 4 things
lungs
kidney
spleen
bones
those with sickle cell disease are at an increased risk for….
pneumococcal infections
fatal sepsis
how is sickle cell disease diagnosed
hemoglobin electrophoresis
true or false
sickle cell disease is autosomal recessive
true
tay sachs disease is targeted where
in the nervous system
what disease is characterized by a red spot in the retina?
how is it inherited?
tay sachs disease
autosomal recessive
explain X-linked dominant pattern
affected males do NOT transmit the mutant allele to their sons
BUT affected males affect ALL of their daughters
these daughters have a 50% chance of transmitting the allele (to either M or F)
both males and females are affected, but women less severely
give an example of an X-linked dominant disorder
Rett syndrome
rett syndrome involves a mutation in what gene?
Methyl-Cp binding protein 2 gene (MECP2) on the X CHROMOSOME
does rett syndrome affect girls, boys, or both?
occurs almost exclusively in girls (mutation on X chromosome)
but there are boys who have a similar mutation – Klinefelter’s Syndrome - have extra X chromosome XXY and die after being born
true or false
there is no known cure for Rett Syndrome
true
explain X-linked recessive pattern
affected male does NOT transmit allele to his sons
ALL daughters of an affected male are CARRIERS and NONE are affected
sons of these carrier females have 50% risk of being AFFECTED
daughters of these carrier females have 5-% risk of being CARRIERS
true or false
in an X-linked recessive pattern, the most affected persons are female
FALSE - most are male
women are carriers.
affected male does not transmit to son, but all of his daughters will be carriers
these carrier daughters have 50% chance of making their sons AFFECTED and 50% chance of making their daughters CARRIERS
Name 3 X-linked recessive disorders
Hemophilia B
XLA (x linked agammaglobulinemia)
Duchenne muscular dystrophy
hemophilia B is caused by what mutation
in the factor IX gene – deficiency of factor IX - blood clotting disorder
XLA is caused by mutation in what gene
in the BTK gene (Bruton Tyrosine Kinase)
explain the pathophysiology of XLA
mutation in BTK gene = no maturation of pro b cells to b cells
antibody production is impaired
recurrent otitis media
