Diseases Flashcards
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.
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
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.
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.
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.
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
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
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
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
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.
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
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
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
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
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