Flashcards in Diseases Deck (28):
1
Hemophilia:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
X-linked Recessive
Clotting Factor VIII/IX
Deficiency in clotting factor interferes in normal clotting to prevent bleeding
Recurrent internal and external bleeding episodes. Bruise/Hematoma formation.
2
Fragile X:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
X-linked Recessive
FMR1
Trinucleotide "CGG" expansion causes failure to express FMRP from FMR1 gene
Autism, mental retardation, elongated face, large or protruding ears, flat feet, larger testes (macroorchidism), low muscle tone
3
Rett Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
X-linked (females only)
MECP2
Loss of MECP2 causes cells in the locus coeruleus to have decreased noradrenergic innervation of the brain, leading to neurodegeneration.
Normal development until 6-18 months, followed by stagnation and regression. Smaller than normal head, hands, and feet. Repetitive hand movements.
4
G6PD:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
X-linked Recessive
G6PD
G6PD deficiency causes inability of RBCs to respond to oxidative stress due to reduced activity of PPP
Mostly asymptomatic. Hemolytic anemia in response to oxidative stress. Degmacytes and heinz bodies on an RBC smear.
5
Cystic Fibrosis:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Autosomal Recessive
CFTR
CFTR is a transmembrane chloride channel. Mutation causes inability of epithelial cells to import Cl-.
Salty tasting skin, failure to thrive, accumulation of thick, sticky mucus, frequent chest infections, coughing or shortness of breath.
6
Sickle Cell Anemia:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Autosomal Recessive
HBB -> HbS
Low-oxygen tension promotes red blood cell sickling -> increased red blood cell destruction (anemia) AND blood vessel occlusion
Sickling crises caused by infection, dehydration, acidosis, low oxygen
7
α-Thalassemia:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Other: more common in _
Autosomal Recessive
HBA1, HBA2
HBA1/2 deletion -> Decreased alpha-globin production -> excessive beta-chains that form unstable tetramers with abnormal oxygen dissociation curves
Microcytic hypochromic anemia, heinz bodies, splenomegaly
Africans and Asians
8
β-Thalassemia:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Other: more common in _
Autosomal Recessive
HBB
HBB deletion -> Decreased beta-globin production -> excessive alpha-chains that bind to and damage RBC membranes
Severe anemia, poor growth, skeletal abnormality during infancy
Africans, Greeks, and Italians
9
Marfan Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Autosomal Dominant
FBN1
Fibrillin-1 deficiency causes malformation of areas containing elastin fibers (aorta, ligaments, ciliary zonules of eye)
Tall stature. Long, slender limbs and digits. Abnormally flexible joints. Scoliosis. Sunken/raised chest
10
Ehler-Danlos Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Autosomal Dominant (most types)
Collagen proteins
Mutations cause disruption of the structure, production, or processing of collagen -> weakened connective tissue
Unusually large range of joint movement (hypermobility). Soft, velvety skin that is highly elastic and fragile.
11
Prader-Willi:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Not Inherited
Deletion of paternal 15q11-13/Chromosome 15 maternal disomy
Deletion of snoRNA genes
Hypotonia, feeding difficulties, poor growth, and delayed development during infancy. Later: Insatiable appetite -> Hyperphagia and obesity
12
Angelman Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Not Inherited
Deletion of maternal 15q11-13/Chromosome 15 paternal disomy
Loss of UBE3A gene -> loss of gene product in certain areas of the brain
Delayed development, intellectual disability, severe speech impairment, ataxia, epilepsy, microcephaly
13
Huntington Disease:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Other: # repeats = ?
Autosomal Dominant
HTT
Trinucleotide "CAG" expansion -> abnormally long Huntingtin protein that is cut into smaller, toxic fragments that accumulate in neurons
Progressive brain disorder that causes uncontrolled movements (chorea), emotional problems, and loss of cognition
55 = juvenile onset
14
Down Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Not Inherited
Trisomy 21
Trisomy 21 disrupts normal course of development
Characteristic facial appearance, hypotonia in infancy, cognitive development delays
15
Phenylketonuria:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Other: other forms of _ affect other proteins in the _ metabolism pathway
Autosomal Recessive
Phenylalanine hydroxylase, Dihydrobiopterin reductase
Inability to metabolize phenylalanine -> Toxic buildup of phenylalanine in body (particularly neurons)
Infants are fine until toxic levels of Phe build up -> intellectual disability, seizures, delayed development
hyperphe, phenylalanine
16
Ornithine Transcarbamylase Deficiency:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
X-linked recessive
OTC
OTC mutation -> OTCase deficiency -> orotic acid buildup and hyperammonemia
Symptoms evident within first few days of life: lethargy, poor feeding, poorly controlled breathing rate and body temperature, seizures, coma
17
Xeroderma Pigmentosum:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Other: variant can be caused by mutation in _
Autosomal Recessive
Nucleotide excision repair (NER) enzymes
Buildup of unrepaired DNA damage from UV radiation -> cancerous tumors
Severe sunburn after minimal sun exposure, freckling in sun-exposed areas, dry skin, changes in skin pigmentation
error-free polymerase
18
Autism:
Inheritance Pattern
Presentation
Multifactorial
Markedly abnormal or impaired development in social interaction and communication. Symptoms usually appear before age 3
19
Duchenne Muscular Dystrophy:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
X-linked recessive
DMD
DMD mutation -> dystrophin deficiency -> extensive damage to skeletal and cardiac muscle
Muscle weakness, delayed motor skills, usually wheelchair-dependent by adolescence, cardiomyopathy
20
Patau Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Not Inherited
Trisomy 13
Trisomy 13 disrupts normal course of development
Severe intellectual disability, heart defects, brain/spinal cord abnormalities, very small eyes, polydactyly, cleft lip
21
Edwards Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Not Inherited
Trisomy 18
Trisomy 18 disrupts normal course of development
Severe intellectual disability, heart defects, microcephaly, small jaw/mouth
22
Cri du Chat:
Inheritance Pattern
Affected Genes/Proteins
Presentation
Not Inherited
Chromosome 5p deletion
High-pitched sound like a cat, intellectual disability, delayed development, microcephaly, hypertelorism, low-set ears, small jaw
23
Turner Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Presentation
Not Inherited
X0
Short stature, webbed neck, widely-spaced nipples
24
Klinefelter Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Not Inherited
XXY
Extra copies of X-chromosome interfere with male sexual development
Reduced testosterone production, incomplete puberty, breast enlargement, small testes, infertility
25
Trisomy X:
Inheritance Pattern
Affected Genes/Proteins
Presentation
Not Inherited
XXX
Usually does not cause an abnormal phenotype. Tall stature, learning disabilities, delayed development
26
Retinoblastoma:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Autosomal dominant
RB1
Mutations in RB1 (TSG) -> uncontrolled proliferation of retinal cells
Cancer of the retina that usually develops in early childhood. Presents as "cat's eye reflex" (whiteness in the pupil).
27
Bloom Syndrome:
Inheritance Pattern
Affected Genes/Proteins
Etiology
Presentation
Autosomal recessive
BLM
Mutations in BLM -> RecQ helicase deficiency -> increased chromosomal instability -> cancer
Short stature, sun-sensitive skin changes, increased risk of cancer
28