General genetics / metabolic 4 Flashcards
connexin 26
the protein produced by the GJB2 gene
connexin 30
the protein produced by the GJB6 gene
DFNB1
definition
features
cause
- non-syndromic hearing loss and deafness
- congenital, profound deafness (non-syndromic)
- caused by mutations (AR) in GJB2 and GJB6 genes
Waardenburg syndrome
features
gene(s)
inheritance
- pigmentary abnormalities (white forelock; irises); sensorineural hearing loss
- many genes
- AD inheritance
- *most common type of AD syndromic hearing loss**
Brachio-oto-renal syndrome
features
gene(s)
inheritance
- hearing loss; branchial cleft cysts; renal anomalies; ear pits
- many genes
- AD inheritance
- *second most common type of AD syndromic hearing loss**
Treacher Collins syndrome
features
gene(s)
inheritance
- ear abnormalities -> hearing loss; hypoplasia of mandible; colobomas of lower eyelids; cleft palate; trach
- TCOF1 gene
- AD
Stickler syndrome
features
gene(s)
inheritance
- progressive hearing loss; midfacial underdevelopment and cleft palate (Robin sequence); ocular findings
- COL.. genes
- AD inheritance
Usher syndrome
features
gene(s)
inheritance
- sensorineural hearing loss; retinitis pigmentosa
- several genes
- AR inheritance
- *most common type of AR syndromic hearing loss**
Pendred syndrome
features
gene(s)
inheritance
- hearing loss; euthyroid goiter
- many genes
- AR inheritance
- *second most common type of AR syndromic hearing loss**
Jervell and Lange-Nielsen syndrome
features
gene(s)
inheritance
- sensorineural hearing loss; prolonged QT interval; syncope/sudden cardiac death
- KCN.. genes
- AR inheritance
Alport syndrome
features
gene(s)
inheritance
- progressive sensorineural hearing loss after age 10y; renal disease; opthalmalogic findings
- several genes
- all inheritance types, most common: XL
Fragile X
features
gene(s)
inheritance
- affected males: moderate ID; hypotonia; recurrent otitis media; DD; hyperactivity; hand-flapping/biting; impulse control problems; large head and characteristic facies
- FMR1 gene
- XL inheritance
Fragile X
repeat breakdown
- CGG trinucleotide repeats
- intermediate (45-54) may expand
- premutation (55-200) may expand
- full (>200) results in methylation of FMR1 gene
Fragile X
what percentage of affected individuals have deletions or point mutations?
<1%
FXTAS
features
gene(s)
inheritance
- Fragile X - associated tremor/ataxia syndrome; diagnosed by white matter lesions on MRI; onset >50y
- FMR1 gene; male and female with premutation at risk for
- XL inheritance
FXPOI
features
gene(s)
inheritance
- Fragile X - related primary ovarian insufficiency; cessation of menses <40y
- FMR1 gene; female premutation carriers at risk for
Name 2 cardiomyopathies
- hypertrophic cardiomyopathy (HCM)
- arrhythmogenic right ventricular cardiomyopathy (ARVC)
Name 2 hereditary arrhythmias
- Long QT syndrome
- Brugada
Name 1 familial lipid disorder
Familial hypercholesterolemia (FH)
Do hereditary arrhythmias involve structural changes to the heart?
no
Do cardiomyopathies involve structural changes to the heart?
yes
Alpha-1 antitrypsin deficiency
features
gene(s)
inheritance
- may cause lung and liver disease in adulthood
- SERPINA gene
- autosomal codominant
Which metabolic disorder can mimic Marfan syndrome?
homocystinuria
Which metabolic disorder is more common among Mennonites?
MSUD
