1. Medicine, I. of. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. (1998). doi:10.17226/6015
2. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

ALLELE
An allele is a variant form of a gene that is located at a specific position, or genetic locus, on a specific chromosome. Humans have two alleles at each genetic locus, with one allele inherited from each parent.
CHROMOSOME
A chromosome is a thread-like structure of DNA that carries hereditary information, or genes. Human cells have 22 chromosome pairs plus two sex chromosomes, giving a total of 46 per cell.
DISEASE PREVALENCE
The proportion of individuals in a population having a disease or characteristic. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time, whereas incidence refers to the number of new cases that develop in a given period of time.
DNA
DNA, or deoxyribonucleic acid, is the main component of chromosomes and the carrier of genetic information in nearly all living organisms. DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C).
GENE
A hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome. Genes are transferred from a parent to offspring, and are responsible for the physical and heritable characteristics or phenotype of an individual.
GENETIC VARIANT
An alteration in the most common DNA nucleotide sequence. The variant can be benign, pathogenic or of unknown significance. SNPs are the most common type of genetic variation.
GENOTYPE
The genetic makeup of an individual organism. It may also refer to just a particular gene or set of genes carried by an individual. The genotype determines the phenotype, or observable traits of the organism.
ODDS RATIO
The odds ratio is a way of comparing whether the odds of a certain outcome is the same for two different groups. In this report, the odds ratio estimates the probability of a condition occurring in a group of people with a certain genetic variant compared to a group of people without that variant.

An odds ratio of 1 means that the two groups are equally likely to develop the condition. An odds ratio higher than 1 means that the people with the genetic variant are more likely to develop the condition, while an odds ratio of less than 1 means that the the people with the variant are less likely to develop the condition.
PHENOTYPE
A description of an individual’s physical characteristics, including appearance, development and behaviour. The phenotype is determined by the individual’s genotype as well as environmental factors.
POPULATION ALLELE FREQUENCY
The allele frequency represents the incidence of a gene variant in a population. Alleles are variant forms of a gene that are located at the same position, or genetic locus, on a chromosome.
SNP
Single nucleotide polymorphisms, frequently called SNPs, are the most common type of genetic variation among people. A SNP is a variation in a single nucleotide that occurs at a specific position in the genome.