Comprehensive analysis of circulating viral DNA in maternal plasma at population-scale using low-pass whole-genome sequencing

As the most readily adopted molecular screening test, low-pass WGS of maternal plasma cell-free DNA for aneuploidy detection generates a vast amount of genomic data. This large-scale method also allows for high-throughput virome screening. NIPT sequencing data, yielding 6.57 terabases of data from 187.8 billion reads, from 12,951 pregnant Turkish women was used to investigate the prevalence and abundance of viral DNA in plasma. Among the 22 virus sequences identified in 12% of participants were human papillomavirus, herpesvirus, betaherpesvirus and anellovirus. We observed a unique pattern of circulating viral DNA with a high prevalence of papillomaviruses. The prevalence of herpesviruses/anellovirus was similar among Turkish, European and Dutch populations. Hepatitis B prevalence was remarkably low in Dutch, European and Turkish populations, but higher in China. WGS data revealed that herpesvirus/anelloviruses are naturally found in European populations. This represents the first comprehensive research on the plasma virome of pregnant Turkish women.

The spectrum of HNF1A gene mutations in patients with MODY 3 phenotype and identification of three novel germline mutations in Turkish Population

BACKGROUND

Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes mellitus characterized by autosomal dominant inheritance, early age of onset, and pancreatic beta cell dysfunction. Heterozygous mutations in several genes may cause MODY.

METHODS

In the present study, we investigated the molecular spectrum of HNF1A (hepatocyte nuclear factor 1a) mutations, in the individuals referred to a reference center for molecular genetic analysis. Mutations screening was performed in a group of 136 unrelated patients (average age 17.22 years) selected by clinical characterization of MODY. Mutation screening involved direct sequencing of the HNF1A gene.

RESULTS

Among 136 individuals analyzed, 10 were carrying heterozygous HNF1A mutations, 3 of them being novel. Clinical features, such as age of diabetes at diagnosis or severity of hyperglycemia, were not related to the mutation type or location. No clear phenotype - genotype correlations were identified.

CONCLUSIONS

As a conclusion MODY resulted from HNF1A mutations shows heterogeneity at both phenotypic and molecular levels in Turkish population.