On September 7, 2023, unidentified human remains were discovered in the Glockner Group of the Hohe Tauern (Austrian Alps). Preliminary investigations into the identity of the deceased led to a mountaineer who had been missing for 52 years. To confirm this, DNA analysis was performed. Despite the prolonged postmortem interval, high-molecular-weight DNA was successfully extracted and proved suitable for downstream analysis.

Four half-nieces were identified as potential reference samples. According to information provided by the investigators, they were the daughters of the missing person’s maternal half-sister. The identification strategy utilized mitochondrial DNA (mtDNA) sequencing, as well as autosomal and X-chromosomal STR markers. Given the reported maternal half-sibling relationship, only two of the four half-nieces were initially screened. However, discordant mtDNA haplotypes were observed, one consistent with the decedent and one showing a clear exclusion. Consequently, the half-niece with the non-matching haplotype was removed from further consideration.

Subsequent X-chromosomal markers analysis of the remaining half-niece and the two half-nieces who had not yet been investigated revealed further inconsistencies; two of the three half-nieces shared no common allele at several X-chromosomal loci. It was therefore assumed the half-nieces had two different fathers. However, further analysis revealed two additional incompatibilities, leading to the conclusion that the three half-nieces most likely had three different fathers. This hypothesis was supported by the analysis of 32 autosomal markers with a probability of 99.507%. Despite this, autosomal data alone yielded a low identification probability of only 14.1%. In contrast, calculations based on X-chromosomal markers, assuming the three-father hypothesis, yielded a probability of 99.95%, enabling a definite identification.

Ultimately, the family pedigree had to be revised three times based on genetic data obtained (from “one father / one mother” to “three fathers / two mothers”) before a compatible configuration for biostatistical evaluation could be achieved. While autosomal markers were of limited value for the primary identification, they were essential in reconstructing the true biological relationships (three sisters – three fathers). The analysis of X-chromosomal markers proved decisive and corroborated the mtDNA findings.

This case highlights that information regarding kinship provided by investigators must be critically scrutinized to prevent false exclusions. By integrating mtDNA, 32 autosomal markers, and 12 X-chromosomal markers, a successful identification was achieved despite misleading initial genealogical data.

Disclaimer

The results obtained were used for identification purposes only.

Authors

• Franz Neuhuber (Department of Legal Medicine, University of Salzburg, Austria)
• Jan Cemper-Kiesslich (Department of Legal Medicine, University of Salzburg, Austria)
• Bettina Dunkelmann (Department of Legal Medicine, University of Salzburg, Austria)
• Ines Grießner (Department of Legal Medicine, University of Salzburg, Austria)
• Martin Steinlechner (Institute of Legal Medicine, Medical University of Innsbruck, Austria)
• Petra Hatzer-Grubwieser (Institute of Legal Medicine, Medical University of Innsbruck, Austria)