The Advantage of WGS in Clinical Specialties: From Symptoms to Molecular Diagnosis

At first glance, these conditions may seem unrelated. Yet they often share the same diagnostic challenge: the true cause may be hidden in the genome.

Traditional diagnosis relies on clinical symptoms, laboratory tests, imaging, pathology, organ-specific evaluation, and family history. These tools remain essential. However, for complex, early-onset, familial, or multi-system diseases, they may not fully explain why the disease occurs, why it progresses, or why multiple family members are affected.

This is where whole-genome sequencing, or WGS, can provide additional clinical value.

Why WGS Matters Across Clinical Specialties

Whole-genome sequencing analyzes the genome more comprehensively than single-gene testing or small targeted panels. Rather than focusing only on one suspected disease category, WGS provides a broader view that may help clinicians evaluate multiple genes and variant types in one test.

This can be especially useful when:

• clinical features overlap across different diseases

• the patient has symptoms involving more than one organ system

• the condition appears at a young age

• family history suggests inherited risk

• previous testing was negative or inconclusive

• the suspected disease is genetically heterogeneous

• future reanalysis may be valuable as new evidence emerges

The advantage of WGS is not simply that it “tests more genes.” Its value lies in connecting clinical presentation with molecular evidence, helping clinicians move from symptom-based classification toward precision diagnosis.

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ACTInherit: A WGS Solution for Complex Hereditary Diseases

ACTInherit is ACT Genomics’ whole-genome sequencing service designed to support the evaluation of suspected hereditary diseases.

By analyzing genome-wide information, ACTInherit may help detect different types of genetic variants, including single-nucleotide variants, small insertions and deletions, copy number variations, structural variants, mitochondrial variants, and selected non-coding or intronic variants, depending on the case and analysis strategy.

ACTInherit is especially relevant when the clinical question cannot be easily answered by a single-gene test or narrow panel. For patients with complex or unresolved disease presentations, WGS can provide a more comprehensive basis for clinical interpretation, family risk assessment, and long-term care planning.

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Specialty Spotlight: Nephrology

In nephrology, hereditary kidney diseases are an important cause of chronic kidney disease and end-stage kidney disease, especially in patients with early-onset disease, unexplained kidney failure, persistent hematuria or proteinuria, cystic kidney disease, suspected Alport syndrome, or family history of dialysis or kidney transplantation.

Kidney diseases are genetically heterogeneous, which means similar symptoms may be caused by different genes. For example, persistent hematuria and proteinuria may be associated with COL4A3, COL4A4, or COL4A5 variants in Alport spectrum disorders. Focal segmental glomerulosclerosis, or FSGS, may be related to podocyte gene variants or may represent a collagen IV-related condition. Cystic kidney disease may involve PKD-related genes, nephronophthisis, ciliopathies, or syndromic kidney disorders.

These examples show why a broader genomic view can be valuable. If testing is limited to a single suspected diagnosis, the true molecular cause may be missed.

For patients with unexplained CKD or ESKD, early-onset kidney disease, familial kidney disease, suspected Alport syndrome, cystic kidney disease, CAKUT, tubulointerstitial disease, or kidney disease with extrarenal manifestations, ACTInherit WGS may help clarify molecular diagnosis, support disease classification, guide family testing, inform transplant-related decisions, and reduce unnecessary repeated investigations.

In the era of precision nephrology, kidney disease diagnosis should no longer stop at “unknown cause” when genetic clues may still be present.

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Specialty Spotlight: Cardiology

In cardiology, inherited cardiovascular diseases may present as hypertrophic cardiomyopathy, arrhythmia, unexplained syncope, sudden cardiac arrest, sudden cardiac death in the family, or familial hypercholesterolemia.

Genetic information can be important because it may influence diagnosis, risk stratification, surveillance, treatment planning, and cascade testing for family members.

For example, not all left ventricular hypertrophy represents classic sarcomeric hypertrophic cardiomyopathy. While traditional HCM testing often focuses on sarcomere genes such as MYH7, MYBPC3, TNNT2, TNNI3, TPM1, MYL2, MYL3, and ACTC1, some patients may actually have HCM-like phenocopies such as Fabry disease, Danon disease, PRKAG2 syndrome, mitochondrial disease, or other metabolic conditions. These distinctions matter because they can influence organ monitoring, treatment strategy, and family risk management.

Familial hypercholesterolemia is another example. Traditional FH testing often focuses on genes such as LDLR, APOB, PCSK9, and LDLRAP1. However, some patients with classic FH-like features may have negative panel results or more complex variant types. A broader genomic approach may help preserve more complete variant information for future interpretation or reanalysis.

ACTInherit WGS may support evaluation of inherited cardiomyopathies, arrhythmia syndromes, sudden death risk, and familial hypercholesterolemia, especially when prior panel testing is negative or the phenotype is complex.

In inherited cardiovascular disease, WGS can support a shift from post-event treatment to proactive risk identification and prevention.

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Specialty Spotlight: Dermatology

In dermatology, hereditary skin diseases often begin with visible signs such as blistering, skin fragility, ichthyosis-like scaling, pigmentation changes, café-au-lait macules, hair or nail abnormalities, or neurofibromas.

Although the skin findings are visible, the underlying cause may involve genes related to epidermal structure, keratinization, pigmentation, DNA repair, tumor susceptibility, neural crest development, or multi-organ syndromes.

For example, neonatal blistering may involve genes such as KRT5, KRT14, COL7A1, LAMA3, or LAMB3, which are related to epidermolysis bullosa and basement membrane zone function. Scaling and abnormal keratinization may involve genes such as TGM1, ABCA12, ALOX12B, NIPAL4, or FLG. Pigmentation disorders may be associated with genes such as TYR, OCA2, SLC45A2, MITF, PAX3, or SOX10.

NF1-related disorders also illustrate why broader testing may be important. Patients may present with café-au-lait macules, neurofibromas, or other neurocutaneous signs, but the underlying NF1 variant may appear as a point variant, large deletion, copy number variation, mosaicism, or even a deep intronic variant.

For conditions such as epidermolysis bullosa, inherited ichthyosis, pigmentary disorders, NF1-related disorders, and other genodermatoses, ACTInherit WGS may help support molecular diagnosis, precise subtyping, prognosis assessment, interdisciplinary care planning, reproductive risk counseling, and family cascade testing.

For dermatology, WGS helps connect visible skin phenotypes with hidden genomic etiologies.

From Specialty Diagnosis to Precision Medicine

Across nephrology, cardiology, dermatology, and other specialties, the same principle applies: when a disease is complex, early-onset, familial, or unresolved, a molecular diagnosis may provide important clinical direction.

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WGS can help clinicians:

• identify hidden genetic causes

• clarify disease classification

• support prognosis and monitoring

• inform treatment or management decisions

• guide family risk assessment

• support cascade testing

• enable future reanalysis as new evidence emerges

For patients and families, a molecular diagnosis may provide an explanation for a long diagnostic journey and support more informed care planning.

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A Weekly Specialty Series on WGS in Clinical Care

This article introduces the broader advantage of WGS across clinical specialties. In the coming weeks, ACT Genomics will explore how ACTInherit WGS may support precision diagnosis in specific fields, including nephrology, cardiology, dermatology, and other hereditary disease areas.

Each specialty presents different clinical questions, but the goal remains the same: to help clinicians and families move from uncertainty toward clearer molecular understanding.

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Disclaimer

This content is provided for informational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Any testing or treatment decisions should be made by qualified healthcare professionals based on each patient’s individual condition and the latest clinical evidence.

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