Flashcards in Diseases Deck (20):
Gout and Lesh Nyhan diseases; cause and symptoms
defects in enzymes that add bases to the phosphosugars. Phosphoribosyl synthetase for gout and hypoxanthine guanine phosphoribosyl trasferase for lesh nyhan. this causes the purine bases accumulation of low-solubility-purines in tissues. Kidney issues, and in males, LN can cause self-destructive tendencies.
Mutation in TATA box of Beta Globin Gene, in promotor. An inherited anemia due to deficient production of beta-globin protein by erythroid cells. Also can be due to issues in alphahelices of hemoglobin
mutation in TFIIH, disrupting DNA repair function, so the cell is not able to repair the damage done to skin cells by UV light. lesions form.
Or by damage to Global genome NER system
Caused by defects in transcriptional activity of TFIIH. Symptoms are photo sensitivity, scaly skin, neurological abnormalities, developmental defects
Or by damage to Txn coupled NER system
Caused by defects in transcriptional activity of TFIIH. Lower level of unSymptoms are brittle hair, ichthyosis, scaly skin, neurological abnormalities, developmental defects.
Spinal Muscular Atrophy
Most common fatal disorder in Children, due to degeneration of motor neurons. Caused by mutations in SMN1. But medically caused alternative splicing of SMN2, which differs from SMN1 in that it does not include exon 7, can cause SMN2 to now boost inclusion of exon 7, and improve survival of children.
Abnormal splicing of fibrilin gene. the mutations happen close to splice sites. Symptoms: being big, tall, protruding sternum, weakness of aorta.
CD44 abnormal splicing
This is a cell surface protein involved in cell migration, and abnormal splicing can indicate metastatic potential.
Caused by mutation in polyadenylation signal, in the alpha 2 globin gene.
Cancer and polyA
Cancer cells can also have shorter PolyA chains, have a shorter 3'UTR,
HNPCC (hereditary non-polyposis colorectal cancer, aka Lynch Syndrome)
Mutations in mismatch repair genes. HNPCC is one of the most common inherited cancer-susceptibility
syndromes and accounts for ~5% of all cases of colon cancers.
gamma delta beta thalassemia
due to deletion of the locus control region (LCR) of the -globin gene cluster
Hemophelia B leyden
Is an X-linked disorder that affects clotting. defect in promoter of Factor IX, preventing binding of proper txn activators. pre-pubescent males have 1% of clotting factors they need. After puberty, the androgen receptor can bind and activate at the promotor, resulting in 60% of the clotting factors
fragile X syndrome
There are a lot more CGG repeats (200 vs. 6-50,) in the 5' end of the FMR1 gene, so it is more highly methylated and the FMR1 gene is increasingly transcriptionally silenced. This disease is characterized by mental retardation, dysmorphic facial features, and postpubertal macroorchidism.
Mutation in homeodomain of MSX2, making it hyperactive. This affects genes that are important for cranial suture closure, causing premature suture closure
Androgen insensitivity disorder
Androgen insensitivity syndrome includes feminization or undermasculinization of the external genitalia at birth, abnormal secondary sexual development in puberty, and infertility. It occurs in males who have mutations in either the DNA binding domain or the ligand binding domain of the androgen receptor (a zinc finger DNA binding protein). This makes the patients less responsive to androgens.
Waardenburg syndrome type II
characterized by deafness, pigmentation anomalies of the eyes, and other pigmentation defects (hair, skin). Mutations in the microphthalmia-associated transcription factor (MITF) gene (which encodes a bHLH DNA binding protein) are observed in 15-20% of the patients. This gene encodes a transcription factor that plays a major role in the development of melanocytes.
mutations in one copy of the CREB binding protein (CBP) gene. CBP is an essential transcriptional coactivator for many different transcription factors and is a histone acetyltransferase. It is normally recruited to many genes to activate transcription, and thus haploinsufficiency can result in widespread transcriptional changes. This is a multisystem disorder that is characterized by growth retardation, mental retardation, craniofacial dysmorphism, abnormally broad thumbs and great toes
Fusions between HATs, HDACs, and transcriptional regulators result in gain of functions, leading to loss of regulation and hematopoietic malignancy