genetic diseases Flashcards
people with this disease have tall, thin body habitus with abnormally long legs, arms, and fingers
Marfan syndrome
Marfan syndrome is an ____ disorder of connective tissue due to mutation of the ____ resulting in abnormal ____, a glycoprotein necessary for normal elastic fiber production
autosomal dominant; FBN1 gene; fibrillin
characterized by hyperextensible skin and hypermobile joints; skin fragility and delayed wound healing
ehlers- danlos syndrome
ehler-danlos syndrome is a problem of ____ with at least 6 different clinical variants
collagen synthesis
diseases caused by mutations in genes encoding receptor proteins or channels
familial hypercholesterolemia- LDL receptor
cystic fibrosis- chloride channel protein
affected patients often have coarse facial features, clouding of cornea, joint stiffness, and mental retardation; seven variants described
mucopolysaccharidoses (type of lysosomal storage disease)
type of MPS; autosomal recessive, caused by deficiency of alpha-L-iduronidase
Hurler disease (MPS type I)
type of MPS; X-linked, deficiency of L-iduronate sulfatase
Hunter syndrome
most common of the chromosomal disorders
Trisomy 21 (down syndrome)
male hypogonadism that develops when there are at least 2 X chromosomes and one or more Y chromosomes (most are 47,XXY)
Klinefelter syndrome
due to partial or complete absence of one of the X chromosomes; characterized by primary hypogonadism in phenotypic females
Turner syndrome
person has a mutant gene but doesn’t or only partially expresses it phenotypically
reduced or incomplete penetrance
trait is seen phenotypically in all individuals having the mutant gene but is expressed differently among individuals
variable expressivity
affected individuals may not have affected parents because their disease arose from a new mutation
de novo mutation
diseases caused by mutations in enzyme proteins
phenylketonuria
galactosemia
lysosomal storage diseases
autosomal recessive disorder that affects 1 in 10,000 caucasian infants
pheylketonuria
types of lysosomal storage diseases
tay-sachs disease
niemann-pick disease
gaucher disease
mucopolysaccharidoses
normal chromosome count is termed ____
euploid
an increased chromosome count that is a multiple of that normally seen (i.e. 3 x 23 or 4 x 23) is termed _____ and generally results in ______
polyploidy; spontaneous abortion
any number that is not an exact multiple of the normal chromosome count is termed _____
aneuploidy
examples of aneuploidy include ____ and ____
trisomy (an extra chromosome, 47); monosomy (absence of a chromosome, 45)
structural abnormalities also occur and these usually result from _____ followed by _____ of material
chromosome breakage; loss or rearrangement
transfer of a part of one chromosome to another nonhomologous chromosome
translocation (structural abnormality)
when fragments are exchanged between two chromosomes
reciprocal translocation
when a chromosome breaks in two points, then the released fragment is reunited after a complete turnaround
inversion
people with down syndrome are susceptible to severe _____ in childhood and have an increased prevalence of _____
periodontal disease; acute leukemia
cytogenetic disorders involving sex chromosomes
klinefelter syndrome and turner syndrome
diagnosis of genetic diseases
fluorescence in situ hybridization (FISH)
comparative genomic hybridization
molecular diagnosis of genetic disorders (includes PCR analysis and restriction enzymes)
4 manifestations of down syndrome
mental retardation
epicanthic folds
flat facial profile
cardiac malformations
