Methodological strategies for mapping HLA susceptibility loci in vitiligo: A focused minireview

Table 1 Main study designs in vitiligo

Type of study	Unit of study	Common techniques
HLA expression	HLA protein levels	Flow cytometry, immunohistochemistry
	HLA mRNA levels	qPCR, RNA-seq, microarray
Case-control	Unrelated case-control, exposure and non-exposure group	Microlymphocytotoxicity, SSP, SSO, qPCR, PCR-RFLP, microarray, SBT, and NGS
Family-based association	Related-case control	SSP, SSO
GWAS	Unrelated case-control, exposure and non-exposure group	RNA-seq, microarray

GWAS: Genome-wide association studies; PCR: Polymerase chain reaction; SSP: Sequence-specific primer; SSO: Sequence-specific oligonucleotide; RFLP: Restriction fragment length polymorphism; SBT: Sequence-based typing; NGS: Next-generation DNA sequencing; RNA-seq: RNA sequencing.