AIM: To describe human leukocyte antigen(HLA) alleles in individuals with Down syndrome and alopecia areata. METHODS: A cross-sectional study was conducted, which evaluated 109 individuals. Ten with down syndrome(DS) and alopecia areata(AA), ten with DS without AA and ten with AA without DS, and their fami-lies. The individuals were matched by gender and age. The following data were computed: gender, age, ethnic group, karyotype, clinical presentation and family history of alopecia areata. Descriptive analysis: measures of central tendency and frequency distribution. Inferential analysis: Fisher’s exact test to compare categorical data between the three groups and Kruskal-Wallis ANOVA test for numerical data.RESULTS: Seventy per cent of evaluated individuals in the DS and AA group were male; presented mean age of 18.6(SD ± 7.2) years and 70% were Caucasian. We observed involvement of the scalp, with a single lesion in 10% and multiple in 90% of subjects. It was observed that there is no significant difference in the frequency distributions of the alleles HLA loci A, B, C, DRB1 and DQB1 of subjects studied. However, according to Fisher’s exact test, there is a trend(P = 0.089) of DS group to present higher proportions of HLA-A 36 and HLA-B 15 than the AA group and AA and DS group.CONCLUSION: There was a tendency for the DS group, to present proportion of HLA-A 36 and HLA-B 15 higher than the AA group and group of individuals with AA and DS. However, there was no significant difference in the frequency distribution of the alleles. AIM: To describe human leukocyte antigen (HLA) alleles in individuals with Down syndrome and alopecia areata. Ten: with cross syndrome (DS) and alopecia areata (AA), ten with DS without AA and ten with AA without DS, and their fami-lies. The individuals were matched by gender and age. The following data were computed: gender, age, ethnic group, karyotype, clinical presentation and family history of alopecia areata. Descriptive analysis: measures of central tendency and frequency distribution. Fisher’s exact test to compare categorical data between the three groups and Kruskal-Wallis ANOVA test for numerical data. RESULTS: Seventy per cent of as individuals in the DS and AA group were The observed mean age of 18.6 (SD ± 7.2) years and 70% were Caucasian. We observed involvement of the scalp, with a single lesion in 10% and multiple in 90% of subjects. It was observed that there is no significant difference in the frequency distributions of the alleles HLA loci A, B, C, DRB1 and DQB1 of subjects studied. However, according to Fisher’s exact test, there is a trend (P = 0.089) of DS group to present higher proportions of HLA-A 36 and HLA-B 15 than the AA group and AA and DS group. CONCLUSION: There was a tendency for the DS group, to present proportion of HLA-A 36 and HLA-B 15 higher than the AA group and group of individuals with AA and DS. However, there was no significant difference in the frequency distribution of the alleles.