Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (690 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The total relative probability, expressed on a logarithmic scale, that a linkage relationship exists among selected loci. Lod is an acronym for logarithmic odds.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Lod Scores; Score, Lod; Scores, Lod.
Where it fits in the MeSH classification
- Broader topics
- Genetic Linkage
Research landscape
PubMed indexes 6,144 records tagged with the MeSH heading “Lod Score” (counts retrieved 2026-10-29). 26 of them (0.4%) were published from 2020 onward, and the busiest period so far is 2000-2009 with 2,985 records.
Reviews account for 152 records (2.5%) and meta-analyses for 23. Randomized controlled trials number 9 (0.1%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 2,463 |
| 2000-2009 | 2,985 |
| 2010-2019 | 670 |
| 2020 onward | 26 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 152 | 2.5% |
| Meta-analyses | 23 | 0.4% |
| Randomized controlled trials | 9 | 0.1% |
Method: PubMed query "Lod Score"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in genetics and genomics
Genetic findings vary widely in strength. A variant linked to a condition in one study may not replicate in other ancestries, and most common variants have small effects that are meaningful only in aggregate. Studies of rare, high-impact variants can support strong causal claims about a gene, while association studies describe statistical links that need functional and independent replication. Check the sample size, the ancestry of participants, whether results were replicated, and whether a laboratory or clinical outcome was actually measured.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Investigation of parent-of-origin effect in comitant strabismus using MOD score analysis | 2009 | Research article Design not recorded in structured metadata | 10 | cc by PMID 19597570 · PMC2709426 |
| Allele frequency misspecification: effect on power and Type I error of model-dependent linkage analysis of quantitative traits under random ascertainment | 2006 | Research article Design not recorded in structured metadata | 10 | cc by PMID 16618369 · DOI · PMC1475629 |
| Linkage analysis in familial non-Lynch syndrome colorectal cancer families from Sweden | 2013 | Clinical trial Design not recorded in structured metadata | 8 | cc by PMID 24349560 · DOI · PMC3859667 |
Investigation of parent-of-origin effect in comitant strabismus using MOD score analysis [1]
Abstract reading summary — source excerpts
- Opening excerpt
- PurposeComitant strabismus is a common pediatric ophthalmic disorder with both genetic and non-genetic factors contributing to its etiology.
- Closing excerpt
- ConclusionsThe results suggest that the parent-of-origin effect may play a role in the etiology of comitant strabismus.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (173 words)
PurposeComitant strabismus is a common pediatric ophthalmic disorder with both genetic and non-genetic factors contributing to its etiology. The aim of the current study is to investigate the phenomenon of a parent-of-origin effect, genomic imprinting, as a possible mode of inheritance in comitant strabismus.MethodsWe performed parametric genome-wide MOD score (model-maximized LOD score) linkage analysis, incorporating imprinting effects, for 382 microsatellite markers in a sample of 258 individuals (117 males and 141 females) from 55 Japanese families with comitant strabismus. We included individuals as affected patients if they presented with comitant esotropia or exotropia based on ophthalmic examination, history taking, or analysis of medical records.ResultsSignificant or suggestive linkage to comitant strabismus with evidence of maternal or paternal imprinting was detected at D4S1575 (4q28.3), D7S486 (7q31.2), D11S1320 (11q24.2), D12S324 (12q24.32), and D19S420 (19q13.11). Using the MOD score approach, we found new evidence of linkage to comitant strabismus at three loci on chromosomes 6q26 (MOD(imp)=MOD(reg)=3.75), 12q24.32 (MOD(imp)=3.36), and 19q13.11 (MOD(imp)=3.79).ConclusionsThe results suggest that the parent-of-origin effect may play a role in the etiology of comitant strabismus.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 19597570 · PMC2709426
Allele frequency misspecification: effect on power and Type I error of model-dependent linkage analysis of quantitative traits under random ascertainment [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundStudies of model-based linkage analysis show that trait or marker model misspecification leads to decreasing power or increasing Type I error rate.
- Closing excerpt
- Thus, with missing parental genotype data, lod-score linkage is not as robust to misspecification of marker allele frequencies as has been commonly thought.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (270 words)
BackgroundStudies of model-based linkage analysis show that trait or marker model misspecification leads to decreasing power or increasing Type I error rate. An increase in Type I error rate is seen when marker related parameters (e.g., allele frequencies) are misspecified and ascertainment is through the trait, but lod-score methods are expected to be robust when ascertainment is random (as is often the case in linkage studies of quantitative traits). In previous studies, the power of lod-score linkage analysis using the "correct" generating model for the trait was found to increase when the marker allele frequencies were misspecified and parental data were missing. An investigation of Type I error rates, conducted in the absence of parental genotype data and with misspecification of marker allele frequencies, showed that an inflation in Type I error rate was the cause of at least part of this apparent increased power. To investigate whether the observed inflation in Type I error rate in model-based LOD score linkage was due to sampling variation, the trait model was estimated from each sample using REGCHUNT, an automated segregation analysis program used to fit models by maximum likelihood using many different sets of initial parameter estimates.ResultsThe Type I error rates observed using the trait models generated by REGCHUNT were usually closer to the nominal levels than those obtained when assuming the generating trait model.ConclusionThis suggests that the observed inflation of Type I error upon misspecification of marker allele frequencies is at least partially due to sampling variation. Thus, with missing parental genotype data, lod-score linkage is not as robust to misspecification of marker allele frequencies as has been commonly thought.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 16618369 · DOI · PMC1475629
Linkage analysis in familial non-Lynch syndrome colorectal cancer families from Sweden [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Family history is a major risk factor for colorectal cancer and many families segregate the disease as a seemingly monogenic trait.
- Closing excerpt
- Sequencing of genes in the regions will be done in future studies.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (247 words)
Family history is a major risk factor for colorectal cancer and many families segregate the disease as a seemingly monogenic trait. A minority of familial colorectal cancer could be explained by known monogenic genes and genetic loci. Familial polyposis and Lynch syndrome are two syndromes where the predisposing genes are known but numerous families have been tested without finding the predisposing gene. We performed a genome wide linkage analysis in 121 colorectal families with an increased risk of colorectal cancer. The families were ascertained from the department of clinical genetics at the Karolinska University Hospital in Stockholm, Sweden and were considered negative for Familial Polyposis and Lynch syndrome. In total 600 subjects were genotyped using single nucleotide polymorphism array chips. Parametric- and non-parametric linkage analyses were computed using MERLIN in all and subsets of families. No statistically significant result was seen, however, there were suggestive positive HLODs above two in parametric linkage analysis. This was observed in a recessive model for high-risk families, at locus 9q31.1 (HLOD=2.2, rs1338121) and for moderate-risk families, at locus Xp22.33 (LOD=2.2 and HLOD=2.5, rs2306737). Using families with early-onset, recessive analysis suggested one locus on 4p16.3 (LOD=2.2, rs920683) and one on 17p13.2 (LOD/HLOD=2.0, rs884250). No NPL score above two was seen for any of the families. Our linkage study provided additional support for the previously suggested region on chromosome 9 and suggested additional loci to be involved in colorectal cancer risk. Sequencing of genes in the regions will be done in future studies.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 24349560 · DOI · PMC3859667
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Factors affecting statistical power in the detection of genetic association [4]
- Research article Score test for detecting linkage to complex traits in selected samples [5]
- Research article On the genetic length of the short arm of the human X chromosome [6]
- Research article The lod score method [7]
- Research article Major strengths and weaknesses of the lod score method [8]
- Research article Extension of the lod score: the mod score [9]
References
- Shaaban S, Matsuo T, Strauch K, Ohtsuki H. Investigation of parent-of-origin effect in comitant strabismus using MOD score analysis. . 2009. PMID 19597570 · PMC2709426
- Mandal DM, Sorant AJ, Atwood LD, Wilson AF, Bailey-Wilson JE. Allele frequency misspecification: effect on power and Type I error of model-dependent linkage analysis of quantitative traits under random ascertainment. . 2006. PMID 16618369 · DOI · PMC1475629
- Kontham V, von Holst S, Lindblom A. Linkage analysis in familial non-Lynch syndrome colorectal cancer families from Sweden. . 2013. PMID 24349560 · DOI · PMC3859667
- Gordon D, Finch SJ. Factors affecting statistical power in the detection of genetic association. J Clin Invest. 2005. PMID 15931375 · DOI · PMC1137002
- Lebrec J, Putter H, Houwelingen JC. Score test for detecting linkage to complex traits in selected samples. Genet Epidemiol. 2004. PMID 15305326 · DOI
- Ropers HH, Wieacker P, Wienker TF, Davies K, Williamson R. On the genetic length of the short arm of the human X chromosome. Hum Genet. 1983. PMID 6315564 · DOI
- Rice JP, Saccone NL, Corbett J. The lod score method. Adv Genet. 2001. PMID 11037316 · DOI
- Ott J. Major strengths and weaknesses of the lod score method. Adv Genet. 2001. PMID 11037318 · DOI
- Clerget-Darpoux F. Extension of the lod score: the mod score. Adv Genet. 2001. PMID 11037317 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.