{"id":6175,"date":"2026-10-19T09:48:35","date_gmt":"2026-10-19T09:48:35","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-gudjon-reykdal-oskarsson\/"},"modified":"2026-10-19T09:48:35","modified_gmt":"2026-10-19T09:48:35","slug":"doktorsvorn-i-lif-og-laeknavisindum-gudjon-reykdal-oskarsson","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-gudjon-reykdal-oskarsson\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00edf- og l\u00e6knav\u00edsindum – Gu\u00f0j\u00f3n Reykdal \u00d3skarsson"},"content":{"rendered":"
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F\u00f6studaginn 15. okt\u00f3ber kl. 11:00 ver Gu\u00f0j\u00f3n Reykdal \u00d3skarsson doktorsritger\u00f0 s\u00edna \u00ed l\u00edf- og l\u00e6knav\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: Mat \u00e1 \u00e1hrifum sjaldg\u00e6fra erf\u00f0abreytileika \u00ed v\u00ed\u00f0t\u00e6kum erf\u00f0amengisleitunum \u00e1 bl\u00f3\u00f0hag. Assessing the effects of rare sequence variants in genome-wide association studies of blood traits.<\/strong><\/p>\n

Andm\u00e6lendur eru dr. Guillaume Lettre, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed Montr\u00e9al og Montreal Heart Institute \u00ed Kanada, og dr. Margr\u00e9t Helga \u00d6gmundsd\u00f3ttir, d\u00f3sent vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands.<\/p>\n

Umsj\u00f3narkennari var dr. Magn\u00fas Karl Magn\u00fasson, pr\u00f3fessor vi\u00f0 L\u00e6knadeild, og lei\u00f0beinandi var Patrick Sulem, MD, yfirma\u00f0ur kl\u00edn\u00edskrar ra\u00f0greiningar hj\u00e1 \u00cdslenskri erf\u00f0agreiningu. Auk \u00feeirra s\u00e1tu \u00ed doktorsnefnd dr. K\u00e1ri Stef\u00e1nsson, forstj\u00f3ri \u00cdslenskrar erf\u00f0agreiningar, dr. P\u00e1ll Torfi \u00d6nundarson, pr\u00f3fessor vi\u00f0 L\u00e6knadeild, og dr. \u00de\u00f3runn Rafnar, deildarstj\u00f3ri krabbameinsranns\u00f3kna hj\u00e1 \u00cdslenskri erf\u00f0agreiningu.<\/p>\n

Dr. \u00de\u00f3rarinn Gu\u00f0j\u00f3nsson, pr\u00f3fessor og deildarforseti L\u00e6knadeildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 11.00.<\/p>\n

V\u00f6rninni ver\u00f0ur streymt:\u00a0<\/p>\n

https:\/\/livestream.com\/hi\/doktorsvorngudjonreykdaloskarsson<\/a><\/p>\n

\u00c1grip<\/strong><\/p>\n

Megin\u00e1hersla mannerf\u00f0afr\u00e6\u00f0innar er a\u00f0 finna samband milli erf\u00f0abreytileika \u00ed erf\u00f0amengi mannsins og sj\u00fakd\u00f3ma og annarra svipger\u00f0a. Samband milli erf\u00f0abreytileika og \u00e1hrifa \u00e1 svipger\u00f0ir getur veitt skilning \u00e1 virkni einstakra gena. Markmi\u00f0 ranns\u00f3knanna \u00ed \u00feessari doktorsritger\u00f0 var a\u00f0 finna samband milli sjaldg\u00e6fra erf\u00f0abreytileika \u00ed tj\u00e1- e\u00f0a spl\u00e6sir\u00f6\u00f0um erf\u00f0amengisins og \u00e1hrifa \u00e1 bl\u00f3\u00f0m\u00e6lingar til a\u00f0 f\u00e1 inns\u00fdn \u00ed l\u00edfe\u00f0lisfr\u00e6\u00f0i svipger\u00f0a \u00ed bl\u00f3\u00f0i.<\/p>\n

Arfger\u00f0arg\u00f6gn eru f\u00e1anleg fyrir st\u00f3ran hundra\u00f0shluta \u00cdslendinga. \u00deessi g\u00f6gn hafa gert tilreikning (e. imputation) mj\u00f6g sjaldg\u00e6fra erf\u00f0abreytileika a\u00f0 m\u00f6guleika sem m\u00e1 svo nota \u00ed svokalla\u00f0ar v\u00ed\u00f0t\u00e6kar erf\u00f0amengisleitanir til a\u00f0 finna samband vi\u00f0 sj\u00fakd\u00f3ma og a\u00f0rar svipger\u00f0ir. Til \u00feess a\u00f0 finna samb\u00f6nd milli sjaldg\u00e6fra erf\u00f0abreytileika og sj\u00fakd\u00f3ma og annarra svipger\u00f0a \u00fearf \u00edtarleg svipger\u00f0arg\u00f6gn fr\u00e1 st\u00f3rum hluta \u00fej\u00f3\u00f0arinnar. \u00dear af lei\u00f0andi notu\u00f0um vi\u00f0 bl\u00f3\u00f0m\u00e6lingar sem h\u00f6f\u00f0u veri\u00f0 m\u00e6ldar af heilsufars\u00e1st\u00e6\u00f0um til a\u00f0 finna samband milli sjaldg\u00e6fra erf\u00f0abreytileika og bl\u00f3\u00f0m\u00e6linga.<\/p>\n

\u00cd \u00feeim ranns\u00f3knum sem voru hluti af \u00feessari doktorsritger\u00f0 var leita\u00f0 a\u00f0 samb\u00f6ndum milli erf\u00f0abreytileika og styrk bl\u00f3\u00f0rau\u00f0a \u00ed bl\u00f3\u00f0i, styrk er\u00ed\u00fer\u00f3p\u00f3\u00edet\u00edns \u00ed bl\u00f3\u00f0i og m\u00e6lingum \u00e1 \u00fatliti kjarna daufkyrninga. \u00cd hverri af ranns\u00f3knunum fannst samband milli sjaldg\u00e6fra erf\u00f0abreytileika og mikilla \u00e1hrifa \u00e1 \u00fe\u00e1 svipger\u00f0 sem var ranns\u00f6ku\u00f0. \u00cd fyrstu ranns\u00f3kn \u00feessarar doktorsritger\u00f0ar fundust 20 samb\u00f6nd milli sjaldg\u00e6fra erf\u00f0abreytileika og styrks bl\u00f3\u00f0rau\u00f0a \u00ed bl\u00f3\u00f0i. \u00c1hugaver\u00f0asta ni\u00f0ursta\u00f0an voru nokkrir sjaldg\u00e6fir erf\u00f0abreytileikar \u00ed ACO1 geninu sem voru tengdir \u00e1hrifum til aukningar e\u00f0a minnkunar \u00e1 styrk bl\u00f3\u00f0rau\u00f0a \u00ed bl\u00f3\u00f0i. Einnig fundust nokkrir erf\u00f0abreytileikar \u00ed PIEZO1 geninu. \u00cd annarri ranns\u00f3kninni, \u00fear sem rannsaka\u00f0ur var styrkur er\u00ed\u00fer\u00f3p\u00f3\u00edet\u00edns \u00ed bl\u00f3\u00f0i, fannst samband milli sjaldg\u00e6fs erf\u00f0abreytileika \u00ed EPOR geninu og h\u00e6kka\u00f0s er\u00ed\u00fer\u00f3p\u00f3\u00edet\u00edns \u00ed bl\u00f3\u00f0i. \u00cd \u00feri\u00f0ju ranns\u00f3kn \u00feessarar doktorsritger\u00f0ar fannst samband milli nokkurra erf\u00f0abreytileika \u00ed LBR geninu og m\u00e6linga \u00e1 \u00fatliti kjarna daufkyrninga.<\/p>\n

Tilreikningur \u00e1 sjaldg\u00e6fum erf\u00f0abreytileikum bygg\u00f0ur \u00e1 heilra\u00f0greiningu st\u00f3rs hundra\u00f0shluta \u00edslenska \u00fe\u00fd\u00f0isins gaf t\u00e6kif\u00e6ri \u00e1 a\u00f0 finna samband milli mj\u00f6g sjaldg\u00e6fra erf\u00f0abreytileika og bl\u00f3\u00f0m\u00e6linga. H\u00e6gt var a\u00f0 nota a\u00f0fer\u00f0ir v\u00ed\u00f0t\u00e6kra erf\u00f0amengisleitana til a\u00f0 finna samband milli fj\u00f6lskyldus\u00e9rt\u00e6ks erf\u00f0abreytileika og bl\u00f3\u00f0m\u00e6linga. A\u00f0 finna samb\u00f6nd erf\u00f0abreytileika me\u00f0 mikil \u00e1hrif \u00e1 bl\u00f3\u00f0m\u00e6lingar hefur veitt inns\u00fdn \u00ed virkni gena sem taka \u00fe\u00e1tt \u00ed l\u00edfe\u00f0lisfr\u00e6\u00f0i bl\u00f3\u00f0sj\u00fakd\u00f3ma og einnig s\u00fdnt fram \u00e1 styrk \u00feeirrar a\u00f0fer\u00f0afr\u00e6\u00f0i sem var notu\u00f0.<\/p>\n

English abstract<\/strong><\/p>\n

The main focus of human genetics is to find associations between sequence variation in the genome and phenotypic variation. Associations of sequence variants with large effect sizes on traits can be very informative to indentify and understand gene function. The aim of the studies included in the thesis was to detect associations of rare variants in coding or splice regions of the genome with large effect sizes on quantitative hematological traits to gain insight into the physiology of hematological phenotypes.<\/p>\n

Genotypic data is available for a large fraction of Icelanders, both by chip-typing on an array or whole-genome sequencing of blood. These data have allowed for imputation of very rare variants that can be used in genome-wide association studies (GWAS) to associate with diseases or other traits. To detect association of these rare variants with diseases or other traits, high coverage phenotype data is required. Therefore, in the study, we used quantitative hematological traits, i.e., measurements from blood tests in clinical practice, to find associations with rare coding or splice region variants.<\/p>\n

In the studies included in the thesis we tested for associations of sequence variants with hemoglobin concentration, serum erythropoietin levels, and measurements of neutrophil nuclear morphology. In each study, we detected association of rare sequence variants with large effect sizes on the studied trait. In the first study included in the thesis, we detected 20 associations of rare variants with hemoglobin concentration. Most noteworthy were several rare sequence variants at ACO1 associated with opposing direction of effect on hemoglobin concentration and also at PIEZO1. In the second study, a study of serum erythropoietin levels, we detected an association of a rare variant in EPOR with higher erythropoietin levels. In the third study, we detected associations of several variants, including very rare variants at LBR associating with measurements of neutrophil nuclear morphology.<\/p>\n

Taken together, using imputation based on whole genome sequencing of a large fraction of the population, allowed us to detect associations of very rare variants associated with hematological quantitative traits. We were able to use GWAS to find associations of family specific variants and hematological traits. Finding these associations of variants and large effect size on quantitative hematological traits has given us insight into the function of genes involved physiology of hematological diseases and demonstrated the strength of the methodology used.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Gu\u00f0j\u00f3n Reykdal \u00d3skarsson er f\u00e6ddur \u00ed Falun \u00ed Sv\u00ed\u00fej\u00f3\u00f0 1. ma\u00ed \u00e1ri\u00f0 1991. Hann lauk st\u00fadentspr\u00f3fi af N\u00e1tt\u00farufr\u00e6\u00f0ibraut vi\u00f0 Fj\u00f6lbrautask\u00f3lann \u00e1 Su\u00f0urlandi \u00e1ri\u00f0 2010. \u00c1ri\u00f0 2014 lauk Gu\u00f0j\u00f3n BS-gr\u00e1\u00f0u \u00ed lyfjafr\u00e6\u00f0i fr\u00e1 H\u00e1sk\u00f3la \u00cdslands og MS-gr\u00e1\u00f0u \u00ed lyfjafr\u00e6\u00f0i \u00e1ri\u00f0 2016. Samhli\u00f0a doktorsn\u00e1mi starfa\u00f0i Gu\u00f0j\u00f3n hj\u00e1 \u00cdslenskri erf\u00f0agreiningu fr\u00e1 haustinu 2016. Foreldrar hans eru \u00d3skar S. Reykdalsson og Brynd\u00eds Gu\u00f0j\u00f3nsd\u00f3ttir.<\/p>\n<\/div><\/div>","protected":false},"featured_media":4932,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2021-10-15T11:00:00+00:00","_phd_date_end":"2021-10-15T14:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Mat \u00e1 \u00e1hrifum sjaldg\u00e6fra erf\u00f0abreytileika \u00ed v\u00ed\u00f0t\u00e6kum erf\u00f0amengisleitunum \u00e1 bl\u00f3\u00f0hag. 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