Genetics and Family History
This chapter describes principles of genetics and family history that are relevant to the practice of clinical endocrinology. It begins with a review of historical eras that provides context for how two seemingly distinct specialties have become intricately interwoven. Genetics concepts are then explained in a progression from basic to complex, each section building on the previous, with clinical examples included to help readers develop a comprehensive understanding without becoming overwhelmed. Topics covered include DNA and RNA structure and function, the genetic code, transcription, translation, exons, introns, gene expression, gene locus, alleles, genotype, phenotype, Mendelian and non-Mendelian patterns of inheritance, epigenetics, gene mutations, chromosomal structural and copy number abnormalities, and cytogenetic and molecular genetic testing methodologies and interpretation.
The Mendelian inheritance section outlines the three laws of Mendelian inheritance and associated inheritance patterns including homozygous and heterozygous, autosomal and pseudoautosomal, dominant and recessive. Non-Mendelian patterns of inheritance described include co-dominance, linkage, sex-linked, multiple alleles, complex polygenic or multifactorial, and mitochondrial.
Gene mutations discussed include point, missense, nonsense, insertion, deletion, duplication, frameshift, substitution, and repeat expansions. Chromosomal abnormalities described include translocations, deletions, duplications, inversions, isochromosomes, dicentric, ring, and aneuploidies resulting from meiotic and mitotic nondisjunction.
The genetic testing section covers karyotyping, fluorescent in situ hybridization, microarrays, gene expression analysis, direct sequencing analysis, and methylation analysis. The section on family history provides information about publicly available tools for collecting genetic and endocrine history data, as well as a detailed description of how to create and use pedigrees to aid in clinical decision-making and communication with patients and their families.
The chapter concludes with a practical discussion of nursing implications, a recommended reading section, and an extensive list of supplemental educational materials and resources. Supplemental materials include a genetics glossary, a list of online resources for information on genetics concepts introduced within the chapter, a list of genetics-based peer-reviewed journals, a list of professional organizations and societies for nurses interested in genetics, and a list of current textbooks on genetics.
The recommended reading section contains a list of online and print publications providing additional in-depth information on genetics in human endocrinology, nursing competencies in genetics, using analogies in patient education, legal and ethical implications of genetics in the clinical setting, issues surrounding disclosure of genetic diagnoses, clinical case studies, interactive pedigree software, epigenetics, molecular genetics testing, gene therapy, additional internet genetics resources, and the future of genetics in endocrinology.
KeywordsGenetics DNA Expression Inheritance Mutation Testing Pedigree
Syndrome causing short stature, unusual facial features, and skeletal abnormalities first identified by researchers named Miller, McKusick, and Malvaux
Array comparative genomic hybridization
Cytosine-adenine-guanine nucleotide sequence
Cyclin dependent kinase inhibitor 1B
Comparative genomic hybridization
Copy number variants or copy number variations
Cytosine-phosphate-guanine (cytosine and guanine separated by a phosphate)
Cytochrome P450 family 21 subfamily A member 2
- del or dn
Familial glucocorticoid deficiency
Fibroblast growth factor receptor 3
Fluorescent in situ hybridization
Fragile X mental retardation 1
Gene expression microarray
Guanine nucleotide-binding protein alpha subunit or g-protein alpha subunit
High-density single nucleotide polymorphism array
Maternally derived chromosome
Multiple endocrine neoplasia type 1 or menin 1
Multiple endocrine neoplasia type 4
Maternally inherited diabetes and deafness or mitochondrial diabetes and deafness
Maturity-onset diabetes of the young type 5
Short arm of a chromosome
Polycystic ovarian syndrome
Polymerase chain reaction
Phosphate regulating endopeptidase homolog X-linked
Protein tyrosine phosphatase, non-receptor type 11
Long arm of a chromosome
Renal cysts and diabetes syndrome
Short stature homeobox
Single nucleotide polymorphism
Single nucleotide polymorphism array
Son of sevenless homolog 1 or SOS Ras/Rac guanine nucleotide exchange factor 1
SRY-box 3 or SRY-related HMG-box 3 (Sex-determining region Y-related high-mobility-group box transcription factor 3)
Sex-determining region Y
Thyroid stimulating hormone
Wild type allele
X chromosome controlling element
X inactive specific transcript
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