Genetic/Chromosomal Abnormalities Flashcards
Genetic disorder characterized by hypotonia, intellectual disabilities, behavioral issues, hyperphagia, and obesity. Its caused by absent expression of paternal genes on chromosome 15.
Prader-Willi
Absent expression of paternal genes on 15q11-13
Prader-Willi
Genetic Imprinting
An epigenetic phenomenon that results in silencing of one of the alleles of a gene depending on whether the allele was paternally or maternally inherited.
Uniparental Disomy
a chromosomal abnormality in which offspring receive two copies of one chromosome from one parent and no copies from the other parent
It is caused by absent expression of the paternally active genes on chromosome 15q11.2q13, either due to deletions from the paternal chromosome, maternal disomy, or an imprinting defect. The vast majority of cases occur sporadically.
Prader Willi
What is the relationship between prader willi and angelman?
Prader Willi was the first genetic disorder attributed to genomic imprinting, meaning that the expression of the gene depends on the sex of the parent donating the gene. PWS arises due to absent paternal expression of the PWS “critical region” on chromosome 15q11.2-q13, whereas loss of the maternal expression of 15q11.2-q13 results in Angelman syndrome.
Loss of expression of maternal UBE3A
Angelman Syndrome, also a disorder of genetic imprinting; related to prader willi
MECP2 mutations
Rett Disorder
Elf like facial features and verbal/social skills that often mask intellectual disabilities
Williams Syndrome
Results from microdeletion on chromosome 7 that inculdes the elastin gene
williams syndrome
What disorder is this most likely:
circulating testosterone levels for a male but failed development of secondary male sex characteristics. Female external genitalia. Blind vaginal pouch. Tend to have elevated testosterone, estrogen, and LH. Genotype is XY.
Androgen insensitivity syndrome!
Happy, excitable, smiles/laughs, has seizure issues, flattened posterior aspect of the head, stiff legs/gait
Angelman Syndrome
Chromostome 15 deletion, maternally inherited
Mom’s Angel
congenital disorder of growth with a predisposition to tumor development. Increased risk of nephroblastoma, hepatoblastoma, neuroblastoma, adrenal tumors.
Beckwith-Wiedmann Syndrome
What is the pathophys/genetic mechanism behind Beckwith-Wiedmann Syndrome
Imprinting!
Chromosome 11p15; it regulates growth. It happens in some cells but not all (mosaicism). (similar to the development of angelman/praderwilli).
