More Genetics Flashcards
Klinefelter syndrome
XXY
Male hypogonadism
Male infertility Eunuchoid body habitus Minimal or no mental retardation Failure of male secondary sex characteristics Gynecomastia with risk of breast cancer Female distribution of hair Atrophic testes Plasma follicle-stimulating hormone and estrogen levels elevated; testosterone levels low
Turner Syndrome
XO
Lymphedema of neck, hands, feet
Webbing of neck
Short stature
Broad chest and widely spaced nipples
Primary amenorrhea
Failure of the development of normal secondary sex characteristics
Severely atrophic and fibrous ovaries (streak)
Congenital heart disease, aortic coarction
Female pseudohermaphrodites
46,XX
Normal ovaries and internal genitalia but ambiguous or virilized external genitalia
Male pseudohermaphrodies
Have a Y
gonads are testes but external genitalia are either ambiguous or completely female.
Fragile X syndrome
Common cause of familial mental retardation
The site on Xq has multiple CGC repeats in the familial mental retardation gene.
Prader Willi Syndrome
Occurs when the paternal 15q12 is deleted, leaving behind only the “silenced” maternal gene product.
Characterized by mental retardation, short stature, hypotonia, obesity, and hypogonadism
Angelman Syndrome
Involves deletion of the maternal 15q12 region, leaving behind only the “silenced” paternal gene.
Characterized by mental retardation, ataxia, seizures, and inappropriate laughter.
Marfan syndrome
Autosomal dominant
Mutation in FBN1 gene on chromosome 15 which gives rise to an abnormal fibrillin protein.
TGFB is secreted excessively to try to compensate- has a deleterious effect on vascular smooth muscle
Morphology
- Skeletal abnormalities
- Ocular changes
- Cardiovascular lesions: mitral valve prolapse. Dilation, dissection, and hemorrhage of the ascending aorta.
Ehlers-Danlos Syndrome
Defective synthesis of structure of fibrillar cartilage.
Tissues rich in collagen are involved in most variants- skin is hyperextensible and strechable, joints are hypermobile, CT is fragile
Familial hypercholesterolemia
Mutation in the gene coding for LDL receptor which is involved in transport/metabolism of cholesterol.
Causes premature atherosclerosis, xanthomas, and increased risk of myocardial infarction
Alkaptonuria (ochronsis)
Lack of homogentisic oxidase leads to the accumulation of homogentisic acid.
Presents with black urine and black pigment throughout the body. Pigments are harmful to joints.
Leber Hereditary Optic Neuropathy
Mitochondrial DNA transmission- progressive loss of central vision
Has a deleterious effect on organs most dependent on oxidation phosphorylation
Diagnosis of congenital infantile fibrosarcoma
Translocation t(12;15)(p13;q25) ETV6-NTKR3 fusion transcript making tyrosine kinase stimulating TAS and PI3K/AKT oncogenic pathways
1 most common malignant neoplasm in childhood and infancy
Acute lymphoblastic leukemia- childhood
Neuroblastoma- infancy
2nd most common solid tumor
Neuroblastoma
