L1:Genetic Basis of Diesease

Question 1

Men 2B

Answer 1

=Multiple Endocrine Neoplasia 2B

• Mucosal Neuromas on tongue and lips - Pathogneumonic if @ commisures of lips
• Medullary thyroid cancer (2-3 yr)
• Pheochromocytoma
• Hypotonea, loose joints, long face (marfanoid)

Question 2

Phenylketonuria (PKU)

Answer 2

=Defect in Phenylalanine Hydroxylase

• Build up of Phenylalanine in body leading mental retardation
• Autosomal Recessive Disease
• Must follow highly restricted diet
• Common in skandinavians
• Fair skin, Eczema
• Seizures and neurologic abnormalities

Question 3

Osteogenesis Imperfecta

Answer 3

Autosomal Dominant disorder causing a defect in Collagen type I

• Brittle Bones
• Easily Broken
• Associated with Dentinogenesis Imperfecta type I
  
  • Everyone with Dentinogenesis Imperfecta type I has Osteogenesis Imperfecta
  • Displays w/ opalescent tooth appearance

Question 4

Achondroplasia

Answer 4

=FGF-3 defect leading to Cartilage malformation

• Autosomal dominant, GAIN of Function Mutation
• Short limbs, trident hand, bowlegged, prominent brow & depressed bridge of nose
• Maxillary hypoplasia can often cause dental problems
• Small foramen magnum results in increased risk for compression of the brainstem
• Homozygous FGF-3 mutation is NOT viable

Question 5

Marfan Syndrome

Answer 5

=Defect in Fibrillin 1 or 2

• Autosomal dominant, LOSS of Function Mutation
• Tall, thin stature with long limbs, fingers and toes
• Narrow and/or sharp featured face
  
  • Narrow mouth w/ a high palate
  • crowded teeth
• Ectopic lenses in eye
• Scolioses and loose joints
• Decreased elasticity of lung tissue, blood vessels, heart valves
  
  • Aortic dissection is most serious complication
  • Can reinforce aorta
• Prominent stretch marks & caved in or pushed out chest

Question 6

Amelogenesis Imperfecta 1E

Answer 6

=X-linked defect in Enamel Matrix Deposition (hypoplastic)

• Small teeth
• Color-yellow brown to brown
• Males: Have thin, very hard, smooth enamel resulting in microdontia
• Females: Vertical furrows in their tooth enamel illustrating the principle of Lyonization.

Question 7

Prader-Willi Syndrome

Answer 7

Epigenetic disorder where there is a deletion of the chromosome 15 that was inherited from the FATHER

• Hypotonia (low muscle tone)
• Obesity
• Mild mental retardation
• Hypogonadism

Question 8

Angelman Syndrome

Answer 8

Epigenetic disorder where there is a deletion of the chromosome 15 that was inherited from the MOTHER

• Ataxic Gait (Marionett syndrome)
• Inappropriate laughter
• Severe mental retardation
• Seizures

Question 9

William’s Syndrome

Answer 9

=Chromosome deletion of 7q11.23

• Microdeletion
• Wide eyes, full lips, small chin, puffy eyes & starburst iris
• wide-spaced, small teeth
• Enamel Hypoplasia
  
  • Increased risk for caries
  • Regular dental hygiene visits & home care required
• Thick, curly hair
• Happy disposition
• Spatial learning deficit (D of y test) - See details but not whole picture
  
  • Normal verbal and social
• Cardiac valve defects

Question 10

Down Syndrome

Answer 10

Trisomy 21 - Have 47 chromosomes (3 copies of 21)

• Leading cause of mental retardation
• Epicanthic folds & flat facial profile
• Simian Crease
• 40% have cardiac malformations
• Increased risk of leukemias & Alzheimer’s disease

Question 11

Klinefelter Syndrome

Answer 11

• Additional X-chromosomes
• Male hypogonadism
• Increased body length
• Testicular atrophy & infertility
• Gynecomastia
• Mild Mental impairment

Question 12

Turner Syndrome

Answer 12

=Single X-xhromosome (No Y-chromosome)

• Webbed Neck
• Low posterior hairline
• Widespread nipples
• Growth retardation
• Failure to develope secondary sex characteristics
• High arched palate
• Aortic & kidney malformations