Genetic Syndromes Flashcards
McCune Albright Syndrome
Mutation in G protein Signaling
Unilateral Cafe au lait spots, polyostotic fibrous dysplasia, precocious puberty, multiple endocrine abnormalities.
Lethal if occurs before fertilization but SURVIVABLE IN PATIENTS WITH MOSAICISM
Prader Willi Syndrome
Chromosome 15
Maternal Imprinting: Gene from momma is normally silent
Paternal Deletion
Hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia
25% of cases due to material uniparental disomy
Angelman Syndrome
Paternal Imprinting: gene from papa is normally silent Maternal deletion Inappropriate laughter (happy puppet), seizures, ataxia, severe intellectual disability 5% if cases due to paternal uniparental disomy
Hypophosphatemic Rickets (Vitamin D resistant Rickets)
X linked dominant
Increased phosphate wasting at PCT, results in rickets like presentation
Mitochondrial Myopathies
Mitochondrial inheritance
Presentation and severity may vary due to heteroplasmy
Secondary to failure of oxidative phosphorylation
Myopathy, lactic acidosis, CNS disease, proximal muscle weakness, dysphagia, ophthalmoplegia, short stature, hearing loss.
Pathonogmonic: RAGGED RED FIBERS
Myoclonic epilepsy with ragged red fibers (MERRF)
Same as mitochondrial myopathies + myoclonic epilepsy!
Polycystic Kidney Disease (PKD)
Autosomal Dominant (ADPKD) Bilateral massive enlargement of kidneys due to multiple large cysts. 85% of cases due to mutations of PKD1 on chromosome 16 (16 letters in polycystic kidney) remainder due to mutations in PKD2 (chromosome 4)
Familial Adenomatous Polyposis
Autosomal Dominant
Colon becomes covered with adenomatous polyps after puberty. 100% of affected progresses to colon cancer unless colon is resected. Mutations on chromosome 5q (APC gene); 5 letters in “polyp.”
Familial Hypercholesterolemia
Autosomal Dominant
Elevated LDL due to defective or absent LDL receptor. Leads to severe atherosclerotic disease early in life, corneal arcus, tendon xanthomas (classically in the Achilles tendon).
Hereditary Hemorrhagic Telangiectasia
Autosomal Dominant
Inherited disorder of blood vessels. Findings: branching skin lesions (telangiectasias), recurrent epistaxis, skin discolorations, arteriovenous malformations (AVMs), GI bleeding, hematuria. Also known as Osler-Weber-Rendu syndrome.
Hereditary spherocytosis
AD
Spheroid erythrocytes due to spectrin or ankyrin defect; hemolytic anemia; MCHC, RDW. Treatment: splenectomy.
Huntington disease
AD
Findings: depression, progressive dementia, choreiform movements, and caudate atrophy. dopamine, GABA, ACh in the brain. Gene on chromosome 4; trinucleotide repeat disorder: (CAG)n. Demonstrates anticipation: repeats age of onset. “Hunting 4 food.”
Li-Fraumeni syndrome
AD
Abnormalities in TP53 multiple malignancies at an early age. Also known as SBLA cancer syndrome (sarcoma, breast, leukemia, adrenal gland).
Marfan syndrome
AD
FBN1 gene mutation on chromosome 15 defective–>fibrin (scaffold for elastin) connective tissue disorder affecting skeleton, heart, and eyes. Findings: tall with long extremities, pectus excavatum, hypermobile joints, and long, tapering ngers and toes (arachnodactyly); cystic medial necrosis of aorta aortic incompetence and dissecting aortic aneurysms; oppy mitral valve. Subluxation of lenses, typically upward and temporally.
Multiple endocrine neoplasias (MEN)
AD (SEE 3 OTHER CARDS FOR EACH TYPE)
Several distinct syndromes (1, 2A, 2B) characterized by familial tumors of endocrine glands, including those of the pancreas, parathyroid, pituitary, thyroid, and adrenal medulla. MEN 1 is associated with MEN1 gene, MEN 2A and 2B are associated with RET gene.
Neuro bromatosis type 1 (von Recklinghausen disease)
AD
Neurocutaneous disorder characterized by café-au-lait spots, cutaneous neuro bromas, optic gliomas, pheochromocytomas, Lisch nodules (pigmented iris hamartomas). Autosomal dominant, 100% penetrance, variable expression. Caused by mutations in the NF1 gene on chromosome 17; 17 letters in “von Recklinghausen.”
Neuro bromatosis type 2
AD
Findings: bilateral acoustic schwannomas, juvenile cataracts, meningiomas, and ependymomas. NF2 gene on chromosome 22; type 2 = 22.
Tuberous sclerosis
AD
Neurocutaneous disorder with multi-organ system involvement, characterized by numerous benign hamartomas. Incomplete penetrance, variable expression.
von Hippel-Lindau disease
AD
Disorder characterized by development of numerous tumors, both benign and malignant. Associated with deletion of VHL gene (tumor suppressor) on chromosome 3 (3p). Von Hippel-Lindau = 3 words for chromosome 3.
MEN1
AD 3 Ps Parathyroid tumors Pituitary tumors (prolactin or GH) Pancreatic endocrine tumors—Zollinger- Ellison syndrome, insulinomas, VIPomas, glucagonomas (rare) Associated with mutation of MEN1 gene (menin, a tumor suppressor)
MEN2A
AD
2Ps
Parathyroid hyperplasia Pheochromocytoma
Medullary thyroid carcinoma (secretes
calcitonin)
Associated with marfanoid habitus; mutation in
RET gene (codes for receptor tyrosine kinase)
MEN2B
AD 1P Pheochromocytoma Medullary thyroid carcinoma (secretes calcitonin) Oral/intestinal ganglioneuromatosis (mucosal neuromas) Associated with marfanoid habitus; mutation in RET gene
Albinism
AR
Normal melanocyte number with melanin production due to tyrosinase activity or defective tyrosine transport. Can also be caused by failure of neural crest cell migration during development. risk of skin cancer.
ARPKD
AR–> Sorry no tricks here
Formerly infantile polycystic kidney disease. Presents in infancy. Associated with congenital hepatic fibrosis. Signi cant oliguric renal failure in utero can lead to Potter sequence. Concerns beyond neonatal period include systemic hypertension, progressive renal insufciency, and portal hypertension from congenital hepatic fibrosis.
Cystic Fibrosis
AR See FA pg 84 for labs and genetics just sx here:
Recurrent pulmonary infections (e.g., Pseudomonas), chronic bronchitis and bronchiectasis reticulonodular pattern on CXR, pancreatic insuficiency, malabsorption with steatorrhea, and nasal polyps. Meconium ileus in newborns. Infertility in males (absence of vas deferens), and subfertility in females (amenorrhea, abnormally thick cervical mucus). Fat-soluble vitamin de ciencies (A, D, E, K).