Key concepts / diseases Flashcards
What is meant by genomic imprinting?
process where only one copy of a gene in an individual is expressed, while the other copy is suppressed by a TAG applied to DNA in egg formation.
Give 4 examples of syndromes caused by genomic imprinting:
- Prada-Willi
- Angleman
- Allbright’s hereditary osteodystrophy
- Beck-with-Weidemann
What is the clinical presentation of patient with Prada-Willi syndrome?
Neonatal hypotonia
Poor feeding
Moderate mental handicap
Obesity (later)
Small genitals
What is the genetic picture of Prada Willi Syndrome?
70% - paternal chromosome 15q
30% - maternal
What is the clinical presentation of a patient with Angleman syndrome?
Unprovoked clapping / laughing
Microcephaly
Sever mental retardation
Ataxia
Seizures
What is the genetic picture of Angleman Syndrome?
80% - maternal chromosome 15q
What is the genetic picture + presentation of Allbright’s hereditary osteodystrophy?
Mutation to GNAs on ch 20q13.
Associated with pseudohypoparathyroidism
Short
Obese
moderate LD
What is the genetic picture of Beckwith - Weidemann syndrome?
Mutation to gene cluster on ch. 11q15.
Large birth weight
Macroglossia
Anterior abdominal wall defect
Describe the mutation (pattern) seen in CF
Mutations to the CFTR gene.
The ^F508 accounts for 75% of mutations.
What does the ^F508 mutation cause?
Deletion of 3 nucleotide codons for phenylalanine residue
