Cytogenetics is the microscopic investigation of the DNA structure/content at the chromosomal level using banding of metaphase preparations 🦓
Banding = darker and lighter areas on a chromosome, which are reproducible across specimens 🦓
Most common type of banding is G-banding:
📌Dark bands: AT-rich, heterochromatic, fewer active genes
📌Light bands: CG-rich, euchromatic, more active genes
From Wikipedia ⬇️
Our talented technologists identify banded chromosomes by assessing (in order):
1️⃣ Chromosome size
2️⃣ Centromere position
3️⃣ Banding pattern
Cytogenetics studies are essential in making a diagnosis of AML with inv 16
🔎 This can be subtle on conventional karyotype, so further testing with FISH/molecular is warranted if the karyotype is normal but the morphology suggests inv 16
The inversion of chromosome 16 (or the translocation t(16;16) leads to the fusion of CBF-beta and MYH11 🧬
CBF normally binds to enhancers/promoters of genes involved in hematopoiesis, increasing transcription of these target genes ➡️ hematopoietic differentiation/maturation
With the fusion gene, this process is blocked 🛑 ➡️ less transcription of target genes ➡️ less hematopoietic differentiation/maturation ➡️ disease
✨ Important to note that AML with inversion 16 is considered to be in the favorable risk category ✨
End 🧵
That’s all for this tweetorial! Thanks for following along 🤗
Again, always learning - I welcome any feedback or suggestions!
But as someone who grew up in the desert ➡️ and then lived in TX 🤠 ➡️ if I can handle it, you definitely can too! (Just need to get yourself some good gear🧥🥾 - I’ve got suggestions!)
If you don’t want to go outside in the winter, Mayo Clinic & Rochester have tunnels & sky bridges connecting the med center w downtown, including from the parking ramps to the hospital 🏥
But personally, I’m excited for outdoor activities like snowshoeing & cross-country skiing!
Catching up on 🧬 “Understanding #NGS and Interpreting Reports for Oncologic Pathology” with Dr. @sabahkadri and Dr. Cecilia Yeung at #CAP21@AMPath 👩🏻💻
📌 @Pathologists has NGS assay development tools regarding test design, validation, quality, and bioinformatics: cap.org/member-resourc…
📌 How much do you want to know? ➡️ what test is needed? (WGS vs WES vs targeted sequencing)
1/
🧬 NGS in a nutshell with Dr. Yeung
1️⃣ Library preparation (hybrid capture vs amplicon-based)
2️⃣ Sequence the fragments of DNA (cyclic reversible termination vs detection of chemical byproducts ⚡️ as single nucleotide is added)
2/
🧬#MolecularPath “Selecting the Right Tool for the Job: Practical Considerations for the Application of Molecular Diagnostics Methods in SurgPath” with @LJTafeMD and Dr. Larissa Furtado
A few takeaways (just scratching the surface of this excellent talk!) ⬇️🧵#MolecularPath_CEJ