> For the complete documentation index, see [llms.txt](https://docs.nested-knowledge.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nested-knowledge.com/get-started/demo-nests/epidemiology-tlr-incidence-and-prevalence-in-ornithine-transcarbamylase-deficiency-otcd.md). # Epidemiology TLR: Incidence and Prevalence in Ornithine Transcarbamylase Deficiency (OTCD) A walkthrough of the economic targeted literature review demo nests on incidence and prevalence in in Ornithine Transcarbamylase Deficiency (OTCD). ### About This Review Ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle disorder, but its true global burden is uncertain — underdiagnosis, inconsistent case definitions, incomplete registry reporting, and limited newborn screening coverage all work against a clean estimate. This nest asks a narrow, specific question: what do published sources report about OTCD's incidence and prevalence, by sex, age group, clinical presentation, and geography? This is a targeted literature review (TLR) since rare disease literature is typically too sparse and too inconsistently reported to pool into a single quantitative estimate. This nest is the one to open if your own work involves a rare or orphan indication. Want to move straight to a Q\&A with the evidence? Jump to Synthesis Chat ### Search **Smart Search** generated AI-assisted queries for PubMed/MEDLINE searched via API integration. Building precise search queries by hand is one of the slower parts of any review — Smart Search compresses that step so the team can move to screening faster. Searching published literature was done at the cost of missing rare disease registries and other grey literature. **Try it yourself:** Tweak the research question yourself and generate a Smart Search.

Smart Search query for ornithine transcarbamylase deficiency. — Smart Search query for the OTCD epidemiology review.

**See also:** [Literature Search](/review-workflow/literature-search.md), [Smart Search](/review-workflow/literature-search/ai-tools-in-search/smart-search.md), and [Other Sources](/review-workflow/literature-search/other-sources.md) ### Screening On the **Configure Screening** page, **Smart Config: Screening** generated the review's eligibility criteria as structured screening questions for use at the Title/Abstract and Full Text stages, which **Smart Screener** then applied consistently to each record.

Configure Screening page showing generated epidemiology eligibility criteria. — Generated eligibility criteria in Configure Screening.

This review is set for a Single Reviewer in Two-Pass screening mode. This review's eligibility criteria don't fit the standard PICO shape — there's no intervention or comparator, since it's a purely epidemiologic question. Smart Config: Screening is useful precisely in a case like this: it takes an atypical PICOS shape (an outcome requirement of at least one incidence or prevalence estimate, with intervention and comparator marked not applicable) and produces well-formed criteria for Smart Screener to apply record by record, rather than leaving each screening decision to individual interpretation of an unusual eligibility structure. **Try it yourself:** Open the main Screening page to view how Smart Screener answered each eligibility criteria for a given study.

Smart Screener answers for an epidemiology record. — Smart Screener evaluates the epidemiology eligibility criteria.

**See also:** [Configure Screening](/review-workflow/screening/configure-screening.md), [Smart Config: Screening](/review-workflow/screening/criteria-based-screening/smart-config-screening.md), and [Smart Screener](/review-workflow/screening/criteria-based-screening/smart-screener.md) ### Tagging and Extraction On the **Configure Tagging** page, the Epidemiology template hierarchy was imported then **Adaptive Smart Tags** extracted a detailed set of epidemiological fields from all study full texts — country or region, study design, population denominator, diagnostic criteria, sex and age distribution, incidence and prevalence estimates with confidence intervals, newborn screening status, and mutation or carrier data where available. Most included sources here contribute just one or two hard numbers — a rate and a confidence interval — buried in very different reporting formats: a registry report reads nothing like a peer-reviewed article, which reads nothing like a conference abstract. Applying the same tag hierarchy across all of them is what lets those numbers land in the same structure afterward, so a rate from a newborn screening report and a rate from a peer-reviewed cohort study end up genuinely comparable rather than just adjacent. **Try it yourself:** Examine applied tags using the icon or open a study in Tagging to view extracted data.

Tagging view showing extracted epidemiology data. — Extracted epidemiology data in Tagging.

Tagging view showing applied epidemiology tags for a study. — Applied epidemiology tags for an included source.

**See also:** [Configure Tagging](/review-workflow/tagging/configure-tagging.md), [Adaptive Smart Tags](/review-workflow/tagging/ai-tools-in-tagging/adaptive-smart-tags.md), and [Apply Tags](/review-workflow/tagging/apply-tags.md) ### Study Inspector **Study Inspector** lets a reviewer check the whole set of included sources at once — especially useful here, since sources range from peer-reviewed articles to registry reports to conference abstracts, and each contributes differently to the final picture. A reviewer working a rare disease epidemiology question would use Study Inspector to, for example: filter to only studies reporting birth prevalence specifically, since the review tracks several distinct prevalence types separately; check which included sources are newborn screening reports versus peer-reviewed studies, since screening intensity itself is a noted source of variability; or export the geography-tagged subset through Download from Inspector to build a region-by-region comparison. **Try it yourself:** Filter to only sources reporting on neonatal-onset OTCD, and compare that subset's reported rates against the late-onset subset.

Study Inspector showing included OTCD epidemiology sources. — Study Inspector for the OTCD evidence set.

**See also:** [Study Inspector](/review-workflow/study-inspector.md), [Filters Available in Study Inspector](/review-workflow/study-inspector/filter-studies/filters-available-in-study-inspector.md), and [Download from Inspector](/review-workflow/study-inspector/download-from-inspector.md) ### Synthesis However a nest is built, opening **Synthesis** surfaces the same set of views automatically, drawing on whatever's already been completed elsewhere in the nest — none of it needs to be built from scratch. **Qualitative Synthesis** generates on its own from applied tags, giving a synthesis-ready view of how those tags translate into findings. The **PRISMA** chart auto-populates the same way from screening decisions, producing a live, auditable count of records at each stage without anyone building it by hand. **Quantitative Synthesis** and **Critical Appraisal** visuals appear alongside these two, but only where that stage was actually completed in the nest — a review that skipped Meta-Analytical Extraction, for instance, simply won't have a Quantitative Synthesis view to show. **Synthesis Chat** is available immediately regardless of how much of the nest is populated — it's a conversational way to query whatever data exists so far, not a view that waits on a specific stage finishing. **Dashboard** is the one exception: it has to be built rather than generated, so it only appears if someone has configured one in this nest. **Smart Insights** are built here– they are generated AI-written text summaries from the extracted data, drawn together into a competitive landscape narrative. **See also:** [Synthesis](/review-workflow/synthesis.md), [Qualitative Synthesis](/review-workflow/synthesis/navigate-synthesis-outputs/qualitative-synthesis.md), [PRISMA Chart](/review-workflow/synthesis/navigate-synthesis-outputs/prisma-chart.md), [Meta-Analytical Extraction](/review-workflow/meta-analytical-extraction.md), [Quantitative Synthesis](/review-workflow/synthesis/navigate-synthesis-outputs/quantitative-synthesis.md), [Critical Appraisal](/review-workflow/critical-appraisal.md), [Critical Appraisal Outputs](/review-workflow/synthesis/navigate-synthesis-outputs/critical-appraisal-outputs.md), [Synthesis Chat](/review-workflow/synthesis/navigate-synthesis-outputs/synthesis-chat.md), [Dashboard Editor](/review-workflow/synthesis/set-up-synthesis-outputs/dashboard-editor.md), and [Smart Insights](/review-workflow/synthesis/set-up-synthesis-outputs/smart-insights.md) #### Dashboard Extracted incidence and prevalence estimates are organized in **Dashboard**, grouped by geography, age at diagnosis, sex-linked inheritance, and neonatal versus late-onset presentation. As with every nest, Dashboard only displays what Search, Screening, and Tagging have already captured — it's a synthesis-side view, not a place to enter new source data. If an estimate on Dashboard looks off, the fix is in the Adaptive Smart Tags extraction behind it, not in Dashboard itself. **Try it yourself:** Maximise the study insight cards to interact with the data, or download table cards to view data in Excel.

Dashboard summarizing OTCD incidence and prevalence estimates. — Dashboard summary of extracted epidemiology data.

**See also:** [Dashboard Editor](/review-workflow/synthesis/set-up-synthesis-outputs/dashboard-editor.md) and [Dashboard in Synthesis](/review-workflow/synthesis/navigate-synthesis-outputs/dashboard-in-synthesis.md) #### Synthesis Chat **Synthesis Chat** is a direct way to ask this nest a specific epidemiological question without building a Dashboard view first — for example, what carrier prevalence has been reported for female heterozygotes, or which geographies have no published estimate at all. **Try it yourself:** Ask Synthesis Chat where the evidence is thinnest — which subgroup or geography has the fewest reporting sources — and see how it surfaces that gap directly.

Synthesis Chat answering an OTCD epidemiology question. — Synthesis Chat response based on extracted epidemiology data.

**See also:** [Synthesis Chat](/review-workflow/synthesis/navigate-synthesis-outputs/synthesis-chat.md) ### Next Steps


Start A Pilot Trial	Set up a pilot trial of Nested Knowledge.	Start a Pilot Trial
Core Concepts	Understand the objects and terminology used in Nested Knowledge.	Core Concepts
Nest Setup	Learn how to set up your review in Nested Knowledge.	Nest Setup
Quickstart	Start building your first nest.	Quickstart

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