Genetic Testing

Question 1

Cytogenetic Analysis

Answer 1

Karyotyping. Detects numerical and structural abnormalities in chromosomes that underlie congenital anomalies, developmental delay, intellectual disability, and cancer. The resolution is about 6-10 million nucleotides.

Question 2

Genetic Testing

Answer 2

Analyzes changes in DNA, RNA, protein, or DNA modifications status which may case disease or influence disease outcomes. Most on DNA determine sequence variations. Clinical utilization includes diagnosis, treatment, and prevention of diverse types of diseases ranging from Mendelian disorders, common complex disease to cancer.

Question 3

Fluorescence in situ Hybridization (FISH)

Answer 3

Cytogenetic technique with a resolution of 200 kb and detects submicroscopic aberrations such as micro-deletions and micro-duplications as well as rearrangements. Does not require fresh specimens and can detect in metaphase and interphase.

Question 4

Chromosome Microarray (CMA)

Answer 4

Comparative genomic hybridization (CGH) array analyzes genomic copy number changes (deletions and duplications). High throughput. Survey entire genome for copy number abberations. High-resolution CGH can detect a resolution of 50 kb. Does not reveal balanced structural rearrangements. ACMGG suggests it as a first-line test.

Question 5

Conventional PCR and Sanger sequencing

Answer 5

Amplify regions of mutation hotspot. Sanger does not detect large deletion duplications. Negative results could have just missed a region.

Question 6

Next Gen Sequencing

Answer 6

Low cost. Several million DNA fragments concurrently. Gene panels (up to several hundred genes), whole exome sequencing, whole genome sequencing. WES has proved to be an effective tool in detecting mutation of Mendelian. Generation exceeds interpretation.

Question 7

Biochemical genetic testing

Answer 7

Intermediate metabolites and enzymatic activities related to metabolism of protein, lipids, carbs, and nucleic acids.

Question 8

Screening Tests

Answer 8

Population screening to ID high risk for early intervention. Further testing or prevention.

Question 9

Newborn Screening

Answer 9

Early detection of common conditions. Errors of metabolism.

Question 10

Carrier Screening

Answer 10

Heterozygous mutation for a recessive disease. Choices in children. Tay-Sachs. Cystic Fibrosis CFTR gene.

Question 11

Prenatal Genetic Testing

Answer 11

Informed decisions for delivering a baby. Fetal Cell-Free DNA can be used for screening in mom.

Question 12

Predictive Genetic Testing

Answer 12

Risk for developing before symptoms. Adult onset like Huntington Disease.

Question 13

Pharmacogenetic Testing

Answer 13

Genes involved with drug metabolism. Response to medications.