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REYKJAVIK, Iceland, July 20, 2021 /PRNewswire=KYODO JBN/ --

Scientist´s from deCODE genetics have mapped 243 sequence variants affecting

fetal growth, separating maternal genome and fetal genome. It sheds light on

the relationships between hypertension, diabetes and fetal growth.

In a paper published in Nature genetics today, Scientists from deCODE genetics,

a fully owned subsidiary of Amgen, report sequence variants that associate with

birth weight and demonstrate how these variants affect birth weight through

both the maternal and fetal genomes. Although birth weight is associated with a

range of health outcomes, it is debated how much these relationships are

through the fetal genome or affected by the intrauterine environment, and hence

the maternal genome.

A total of 243 fetal growth variants are reported and 141 of them were grouped

into four main clusters based on separating the effect of the variant on birth

weight though the maternal versus fetal genome. The majority of variants show

an effect only in the fetus and a quarter of those show evidence of a

parent-of-origin specific effect on birth weight i.e. the effect on the fetus

differs depending on whether the child inherited the variant from the mother or

the father. Some variants have an effect only in the mother but around 30%

affect birth weight both through the maternal and fetal genomes, where for some

the effect is in the same direction, no matter whether from mother or father,

while for others the effect is in opposite directions.

Polygenic risk score analysis of disease-associated variants revealed that

variants associating with blood pressure do not associate with birth weight

when in the maternal genome but in the fetal genome the blood pressure raising

allele correlates with lower birth weight. Variants that associate with risk of

type 2 diabetes associate with birth weight through both the maternal and fetal

genomes but in opposite directions. In the mother, the risk alleles correlate

with higher birth weight but when in the fetus they correlate with lower birth

weight.

"The ability to analyse directly the effect of each of the transmitted alleles

and the maternal non-transmitted allele allows us to separate what happens

through the mother from a direct effect on birth weight through the fetal

genome," says Valgerdur Steinthorsdottir scientist at deCODE Genetics and

author on the paper.

The study reports an expanded GWAS meta-analysis of 400,000 children, 270,000

mothers and 60,000 fathers, combining data from the Icelandic Birth Register

for 125,000 newborns and their parents with public summary level fetal growth

data on children and mothers from the Early Growth Genetics Consortium and UK

Biobank. The effects of the fetal, maternal and paternal genomes on birth

weight were analysed and the study further includes analysis of birth length

and ponderal index.

"It is clear from these results that in our beginnings we are not only shaped

by the half of our maternal genome that is transmitted to us but also the

untransmitted half," says Kari Stefansson CEO of deCODE genetics. "Here we show

how the influence of the two halves can be separated."

Based in Reykjavik, Iceland, deCODE is a global leader in analyzing and

understanding the human genome. Using its unique expertise in human genetics

combined with growing expertise in transcriptomics and population proteomics

and vast amount of phenotypic data, deCODE has discovered risk factors for

dozens of common diseases and provided key insights into their pathogenesis.

The purpose of understanding the genetics of disease is to use that information

to create new means of diagnosing, treating and preventing disease. deCODE is a

wholly-owned subsidiary of Amgen (NASDAQ: AMGN).

Video - https://mma.prnewswire.com/media/1557521/Birth_Weight.mp4

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Source: deCODE genetics