module 11 genetics

Sickle Cell Disease (SCD)

caused by a point mutation with a single nucleotide polymorphism in the gene for the beta chain of hemoglobin

Sickle Cell Disease vs Sickle Cell Trait

SCD is inherited in a homozygous pattern because we need both alleles to express the condition (HbSS) (two carriers). Sickle Cell Trait is inherited in a heterozygous pattern because we can be a carrier and not express it (HbAS) (one carrier)

Sickle Cell Disease (SCD) pathophysiology

amino acid in the sixth position of the beta globin protein is VAL instead of GLU. The mutation forms hemoglobin S instead of A which means RBCs have sickle shape and low O2.

Sickle Cell Disease (SCD) inheritance

Autosomal Recessive

Sickle Cell Disease (SCD) findings

pain during crisis

poor perfusion and oxygenation

organ ischemia

Sickle Cell Disease (SCD) crisis triggers

Infections

High Altitudes

Hot or cold changes

Acidosis

Sickle Cell Disease (SCD) evolution

comes from malaria

Cystic Fibrosis

CFTR protein promotes CL and HCO3 in transport pathways, CFTR mutation can produced formation of thick sticky mucus in lungs, liver, etc and causes atrophy.

Cystic Fibrosis inheritance

autosomal recessive

Cystic Fibrosis diagnosis

Sweat Chloride analysis

Cystic Fibrosis evolution

resistance to cholera and typhus

Duchenne Muscular Dystrophy (DMD)

dystrophin protein mutation prevents functional dystrophin at birth (muscles breakdown)

Duchenne Muscular Dystrophy (DMD) inheritance

X-linked recessive

Classic Hemophilia

Caused by a mutation in the large allele of the F8 gene, which codes for factor VIII clotting.

Prevents thrombin activation, fibrin formation and blood clotting.

Classic Hemophilia inheritance

X-linked recessive

Classic Hemophilia findings

excessive bleeding (females)

bruising easy

joint damage

Classic Hemophilia management

infusions for factor 8

Von Willebrand Disease (VWD)

Mutation in vWF. is produced by vascular endothelial cells and works with factor 8 as a glue to hold prothrombin together. it also activates platelets

VWD type 1 & 2

underdiagnosed

frequent nosebleeds

heavy menses

high postpartum hemorrhage

VWD management

infusions of factor VII

Von Willebrand Disease inheritance

autosomal dominant transmission with reduced penetrance and variable expressivity

Achondroplasia

dwarfism as a result of the mutation FGFR3

Achondroplasia inheritance

autosomal dominant

Achondroplasia causes what in babies

sudden infant death syndrome (SIDS)

Type 1 DM

autoimmune disorder (self attacks self)

virus infects the body and invades many cells, including pancreatic beta cells; it breaks into the cells’ DNA and makes more viruses. White blood cells recognize the viral signal on the infected cells and kills beta cells

Asthma

Chronic inflammatory disease in which IgE is released. Intermittent and reversible airflow obstruction.

Bronchoconstriction and narrowing of the lumen and also increased mucus secretions

Most common type of Asthma

atopic asthma

asthma is

polygenic, there is many variations