Cytogenetic Methods

• Genetic testing is implemented to help individuals who are displaying genetic symptoms in order to improve prognosis and medical treatment/management

Cytogenetic Methods

• Cytogenetics studies the structure, function, and behavior of chromosomes in cells, focusing on their relation to cell behavior during mitosis and meiosis.
• Karyotyping examines the complete set of chromosomes to determine chromosomal abnormalities and sex.
• The human karyotype includes 23 pairs of chromosomes, with the XX or XY configuration determining sex.
• Patau Syndrome (Trisomy 13) stems from an extra copy of chromosome 13, leading to severe physical and mental abnormalities.
• Edwards Syndrome (Trisomy 18) is characterized by three copies of chromosome 18, resulting in specific defects and intellectual disability.
• Down Syndrome (Trisomy 21) often causes developmental delays, intellectual disability, and distinct physical features.
• Cytogenetic analysis uses chromosomes from dividing human cells, like T-lymphocytes, bone marrow, and amniotic fluid cells.
• Modern cytogenetic techniques label gene locations on chromosomes, examine tumor cells, and identify losses or gains of chromosomes and chromosomal translocations.
• Cytogenetics aids cancer management by detecting somatic genetic changes in neoplastic cells, especially in hematological malignancies.

Biochemical Method and DNA Diagnostics

• Polymerase Chain Reaction (PCR) amplifies DNA, enabling detection and analysis from pathogens and genetic mutations
• Cell-free fetal DNA (cffDNA) testing is a non-invasive test that provides early information about the fetus's genetic health and is the most sensitive screening test for conditions like Down syndrome as of 2015
• Newborn screening collects a blood sample from a heel prick to diagnose genetic disorders early
• Prenatal diagnosis detects genetic or chromosomal abnormalities through chorionic villus sampling (CVS), amniocentesis, and non-invasive cell-free fetal DNA (cffDNA) testing to reduce uncertainty and guide pregnancy decisions
• Genetic conditions tested for include Down syndrome, sickle cell anemia, Tay-Sachs disease, and muscular dystrophy
• Sickle cell anemia deforms red blood cells, causing blockages and interactions with normal cells, leading to pain and organ damage
• Tay-Sachs disease is caused by a genetic mutation that leads to the accumulation of harmful substances in neurons resulting in hypotonia and developmental delays and includes a "cherry red spot" in the macula

Muscular Dystrophy

• Muscular dystrophy manifests as progressive muscle weakness and abnormal muscle development
• Congenital muscular dystrophy presents at birth affecting muscle function
• Muscular dystrophy causes weakness and degeneration of the skeletal muscles
• Duchenne Muscular Dystrophy (DMD) is the most common form primarily that appears in early childhood in boys leading to muscle weakness and rapid progression of symptoms
• Becker Muscular Dystrophy is a milder form compared to Duchenne Muscular Dystrophy that appears later in life
• Types of muscular dystrophy appearing in adolescence or early adulthood include Facioscapulohumeral Muscular Dystrophy (FSHD) and Limb-Girdle Muscular Dystrophy (LGMD)
• Facioscapulohumeral Muscular Dystrophy primarily affects facial, shoulder, and upper arm muscles that often appears in late adolescence or early adulthood
• Congenital Muscular Dystrophy presents at birth that effects both males and females that leads to muscle weakness and developmental delays in motor skills during infancy

Reproductive Risks

• Reproductive risks include potential genetic disorders, based on inherited factors.
• Testing and counseling can assess risks like cystic fibrosis, guiding choices such as prenatal testing.
• Cystic fibrosis follows recessive inheritance, and both parents must pass a mutated gene for affectance
• Symptoms of cystic fibrosis include thick mucus, sinusitis, growth issues, lung infections, salty skin, and infertility
• Cystic fibrosis affects cells producing mucus and digestive juices, resulting in thick, sticky secretions and airflow/digestion obstruction
• Screening tests detect early disease evidence and guide further diagnostic testing.
• Patients should seek genetic counseling if screening indicate indicates a risk of a health issue.
• Both parents carrying the cystic fibrosis gene may result in an affected the child.
• "Autosomal recessive" means having two copies of the mutated gene.
• Cystic fibrosis complications include lung infections, respiratory issues, difficulty gaining weight, and infertility.

Explore cytogenetic methods focusing on chromosome structure, function, and behavior during mitosis and meiosis. Learn about karyotyping and chromosomal abnormalities such as Patau Syndrome (Trisomy 13), Edwards Syndrome (Trisomy 18), and Down Syndrome (Trisomy 21). Understand how cytogenetic analysis is conducted using dividing human cells to identify genetic disorders.