BackgroundVast migrations and subsequent assimilation processes have shaped the genetic composition of Southeast Asia, an area of close contact between several major ethnic groups. To better characterize the genetic variation of this region, we analyzed the entire mtDNA control region of 214 unrelated donors from Laos according to highest forensic quality standards. To detail the phylogeny, we inspected selected SNPs from the mtDNA coding region. For a posteriori data quality control, quasi-median network constructions and autosomal STR typing were performed. In order to describe the mtDNA setup of Laos more thoroughly, the data were subjected to population genetic comparisons with 16 East Asian groups.ResultsThe Laos sample exhibited ample mtDNA diversity, reflecting the huge number of ethnic groups listed. We found several new, so far undescribed mtDNA lineages in this dataset and surrounding populations. The Laos population was characteristic in terms of haplotype composition and genetic structure, however, genetic comparisons with other Southeast Asian populations revealed limited, but significant genetic differentiation. Notable differences in the maternal relationship to the major indigenous Southeast Asian ethnolinguistic groups were detected.ConclusionsIn this study, we portray the great mtDNA variety of Laos for the first time. Our findings will contribute to clarify the migration history of the region. They encourage setting up regional and subpopulation databases, especially for forensic applications. The Laotian sequences will be incorporated into the collaborative EMPOP mtDNA database http://www.empop.org upon publication and will be available as the first mtDNA reference data for this country.

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Hb E [beta26(B8)Glu-->Lys], is the most common abnormal hemoglobin (Hb) in Southeast Asian populations. The hitherto highest frequencies of the Hb E gene (HBB*E) in large population samples, approximately 0.3, were observed in the southern part of northeastern Thailand. The finding of even higher frequencies in a small, isolated Austroasiatic group in Northeast Thailand prompted us to examine samples of three Austroasiatic populations in southern Laos (official designation: Lao Theung), an area inhabited by numerous ethnic groups belonging to the Mon-Khmer branch. Blood samples were collected from a total of 603 adult subjects. The HBB*E frequencies were 0.426 in the So of Khammuan Province, 0.433 in the Alak/Ngeh of Sekong Province and 0.253 in the Oy of Attapeu Province. The HBB*E frequencies in the So and Alak/Ngeh are the highest observed in Southeast Asia in representative population samples. None of the common Southeast Asian beta-thalassemia (thal) mutations were found. The results are discussed with respect to natural selection by malaria, selection time, effects of beta-thal and the ethnic history of the population of Southeast Asia.

Newborn skin disorders are quite common and happen to occur during the neonatal period. Most of the birthmarks are transient; however, worried parents often seek medical advice from their child’s physician regarding skin lesions. Thus, it is important to differentiate the skin lesions from pathologic ones to avoid unnecessary diagnostic or therapeutic procedures. This is the first published study in Lao neonates that carried out the data from 4 central hospitals in Vientiane Capital, Lao PDR from September 2019 to February 2020. Among 500 neonates, Sebaceous gland hyperplasia (53%), Mongolian patches (46.6%), and Erythema toxicum neonatorum (30%) were the 3 most common cutaneous conditions found in the Lao newborns. From a clinical point of view, these findings are often a source of parental anxiety and medical concern for inexperienced clinicians.

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