Genetic Disorders Flashcards
(26 cards)
Trisomy 21
epicanthic folds, simian crease, congenital heart defects, prone to leukemia, early onset Alzheimer
Patau Syndrome
3 copies of chromosome 13
cleft lip, cardiac and renal defects, micropthalmia, microcephaly, mental retardation
Edwards Syndrome
three copies of chromosome 18
micrognathia, overlapping fingers, horseshoe shaped kidneys, prominent occiput
Fragile X Syndome
caused by long repeating sequences of three nucleotides
long face, large mandible, large everted ears, large testicles, sometimes mental retardation
*get anticipation between generations
Huntington Disease
CAG repeats in first exon of HTT gene; “gain of function,” AD
leads to production of a toxic protein causing neuronal death
leads to movement disorder and dementia
Hereditary Hematochromatosis
AR caused by excessive iron absorption - leads to fibrosis and liver cirrhosis
cause use restriction enzymes after PCR because the mutation is in an RE site
Marfan Syndrome
AD, caused by mutations in FBN1 and 2 genes and leads to the mutant fibrillin-1 protein which causes loss of structural support in microfibril rich reagions and the increase of TGFbeta signaling
symptoms: long extremities and tall, flexible joints, spinal and chest deformities, cardiovascular lesions, dilation of ascending aorta
Turner Syndrome
X monosomy (can be due to mosaicism or genetic loss of some other kind) leads to short stature, failure of secondary sex characteristic development, atrophy of ovaries, edema and neck swelling - leads to webbed neck later on
Klinefelter Syndrome
XXY, phenotypically male, hypogonadism, infertility, eunichoid appearance, increased estrogen, low testosterone, gynecomastia, failure of secondary sex characteristics to develop
Ehlers Dantos Syndromes
a group of diseases dealing with defective collagen
1. can have AR mutation where you don’t have lysyl hydroxylase which prevents collagen cross-linking
2. you can have AD mutation in type III collagen which causes a dominant negative effect
Symptoms: hyperextensible, vulnerable to trauma, rupture of large arteries
Familial Hypercholesterolemia
Mutation in the LDL receptor, get elevated levels of cholesterol which increases artherosclerosis or possibility of cardiovascular events
xanthomas common
Class II is most common: abnormal LDL receptor folding leads to accumulation in ER
Lysosomal Storage Disorders (in general)
genetic deficiency in lysosomal enzymes
mutations can affecting targeting enzymes for lysosome via mannose-6-phosphate - metabolites accumulate in lysosome
organs with lots of macrophages are affected (spleen, liver)
Tay Sach’s Disease
mutation: hexosaminidase
accumulation: gangliosides
clinical: motor and mental deterioration, blindness, neuronal destruction
Niemann-Pick Disease Type A and B
mutation: sphingomyelinase
accumulation: sphingomyelin
clinical:
A - severe, diffuse CNS involvement, early death, hepatosplenomegaly
B - less severe, no CNS involvement
Niemann-Pick Disease Type C
mutation in NPC1 or NPC2 gene which causes accumulation of cholesterol and gangliosides
leads to hydrops fetalis, neonatal hepatitis, and neurologic disorder
Gaucher Disease
deficiency in glucocerebrosidases, accumulation of glucocerebrosides
Clinical: hepatosplenomegaly
Type I - no neuronal involvement
Type II - immediate neuronal involvement, death in childhood
Type III intermediate between I and II, CNS involvement manifests in adolescence
Mucopolysaccharidoses
a group of disorders resulting from deficiency in enzymes that break down glycosaminoglycans
clinical: coarse facial features, corneal clouding, arterial thickening, mental retardation
* **Clear Cytoplasm is HUGE hint
Hurler Syndrome
a type of mucopolysaccharidosis
due to alpha-1-iduronidase deficiency - early death due to cardiovascular complications
Von Gierke Disease
hepatic form of glycogen storage disease due to glucose-6-phosphate deficiency
get hypoglycemia and glycogen accumulation
McArdle Disease
a myopathic form of glycogen storage disorder resulting from muscle phosphorylase deficiency
causes muscle weakness and cramping post-exercise
Pompe DIsease
whole body glycogen storage disorder resulting from deficiency in acid maltase/alpha glucosidase
causes early death
Alkaptonuria/Ochronosis
AR, lack of homogentisic oxidase leads to phenylalanine and homogentisic acid buildup
dark urine, ochronosis
DiGeorge Syndrome
Chromosome 22q11.2 deletion causing T cell immunodeficiency and hypocalcemia
Velocardiofacial Syndrome
Chromosome 22 deletion causing facial dysmorphology and cardiac malformations
