Orotic Aciduria
Inher, Mech, Pres (Epi + 4), Micro Finding, RX?
AR.
Defect in UMP Synthase ->
Inability to convert Orotic acid -> UMP
(De Novo Pyrimidine Syn pathway).
PRES: Children
FINDING:
- Hypersegmented Neutrophils
RX = UMP (allows bypassing of mutated enzyme)
a-amanitin Ingestion
(found in Amanita phalloides = “death cap” mushrooms)
Mech & Pres?
Inhibits RNA Polymerase II -> Severe hepatotoxicity
I-Cell (Inclusion Cell) Disease
Classification, Mech (3 steps), Pres (3), Labs?
Inherited. Lysosomal Storage Disorder.
MECH:
Defect in Phosphotransferase -> Failure of Golgi to phosphorylate MANNOSE residues on glycoproteins (ie↓mannose-6P) -> Proteins secreted extracellularly rather than delivered to lysosomes.
** Often fatal in childhood. **
PRES:
LABS:
- High lysosomal enzymes
Chediak-Higashi Sx
Genetics, Mech (2), Pres (3)?
Mutation in LYST gene (lysosomal trafficking regulator).
Kartagener’s Sx (1ry ciliary dyskinesia)
Mech, Pres (4), Comp?
Immotile cilia due to defective dynein arm.
PRES:
COMP:
-↑risk of ectopic pregnancy
Osteogenesis Imperfecta (“Brittle Bone Disease”)
Def’n, Inher, Mech, Pres (4)?
Congenital defect of bone RESORPTION -> structurally WEAK bone.
AD.
Deficiency (↓production) of Type 1 Collagen.
Inability to form Procollagen (defective glycosylation of
pro-a-chain hydroxylysine).
PRES:
- “Blue sclera” (thin collagen on sclera => can see underlying
choroidal veins = blue.
THINK: You can see veins under thin skin.)
- Multiple bone fractures with minimal trauma (may occur during birth)
- Hearing loss (fracturing of middle ear bones = ossicles)
- Dental imperfections (lack of dentin)
** May be confused with child abuse **
Ehlers-Danlos Sx
Def’n, Mech (2 steps), Inher, Classification (3 types),
Pres (3), Comp / Assoc (3)?
Deficiency of Type III Collagen (faulty synthesis).
Mutation in Type V Collagen ->
Defective Tropocollagen CROSS-LINKING.
Autosomal.
CLASSIFICATION:
PRES:
COMP / ASSOC:
Menkes Dz
Def’n, Mech (2 steps), Pres (3)?
Connective tis dz.
Impaired Cu abs + transport ->↓activity of Lysyl Oxidase.
PRES:
Alport Sx
Mech (2), Inher, Pres (3)?
XR (MC)
PRES:
Marfan Sx
Mech, Pres (5), Comp (2)?
Fibrillin defect (Fibrillin-1 mutation).
PRES:
COMP:
Familial Hypercholesterolemia
Mech (2 steps), Pres (2)?
Absent / defective LDL receptor ->↑LDL.
PRES:
Mitochondrial Myopathies
List (3), Micro Finding?
FINDING:
- “Ragged red fibers”
Cystic Fibrosis
* MC lethal genetic dz in Caucasians*
Inher, Genetics, Mech (5 steps, 3 effects),
DX, Comp (8: 2 Resp, 4 GI, 1 Repro, 1 Vit), RX (2)?
AR.
Defect in CFTR, chr 7.
MECH:
Defective CFTR ->
Defective Cl channels in lungs, GI tract + sweat glands ->
↑intracel Cl ->
Compensatory↑Na + H20 reabs ->
ECF Na + H20 losses / RENAL K + H wasting.
(Analogous to taking Loop Diuretic)
DX:
-↑Cl (> 60) in sweat
COMP:
RX:
McCune-Albright Sx
Mech, Pres (4)?
Mosaic G-protein signaling mutation.
PRES:
Muscular Dystrophies
3 Types, Inher, General Pres (2)?
INHER: XR (Duchenne + Becker’s)
GENERAL PRES:
Duchenne Muscular Dystrophy
Genetics, Pres (Epi + 2), Lab Findings (2), DX (2), Comp?
FRAMESHIFT Deletion of Dystrophin gene.
PRES: Onset before 5 yrs
LABS:
DX:
COMP:
- Dilated Cardiomyopathy
Becker Muscular Dystrophy
Genetics, Pres (Epi)?
POINT mutation in Dystrophin gene.
PRES: Onset in adolescence / early adulthood
* Less severe than Duchenne *
Myotonic Type I Dystrophy
Genetics, Pres (4)?
CTG trinucleotide repeat expansion in DMPK gene ->
Abnormal expression of Myotonin protein kinase.
PRES:
Fragile X Sx
Genetics, Pres (4)?
Trinucleotide repeat disorder (CGG) ->
Defect affecting expression and methylation of FMR1 gene.
PRES:
Down Sx (Trisomy 21)
Genetics,
Pres (7: THINK: 4 above heart, heart, 2 below heart ),
1st Trimester U/S Findings (2), 2nd Trimester Quad Screen (4),
Comp (3)?
PRES:
1st TRIMESTER U/S:
QUAD SCREEN:
COMP:
Edwards Sx (Trisomy 18)
Pres (Epi + 6: 3 above heart, heart, 2 re extremities),
1st Trimester U/S Finding, 2nd Trimester Quad Screen (4)?
PRES: Infant. Death usually within 1 yr of birth.
1st TRIMESTER U/S:
- PAPP-A ↓
QUAD SCREEN: Everything ↓
Patau Sx (Trisomy 13)
Pres (Epi + 6: 3 above heart, heart, 2 re extremities),
1st Trimester U/S Findings (2)?
PRES: Infant. Death usually within 1 yr of birth.
1st TRIMESTER U/S:
Williams Sx
Genetics, Pres (2), Lab Findings, Comp?
Congenital microdeletion of chr 7 long arm (incl Elastin gene).
PRES:
LABS:
- Hypercalcemia (↑sensitivity to Vitamin D)
Turner Sx (45 XO)
Pres (7)?
PRES: