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Research paper

Tatton-Brown-Rahman Syndrome — GeneReviews

Authoritative reference on TBRS. Cardinal features: tall stature, macrocephaly, intellectual disability, subtle facial gestalt. Afebrile seizures ~20%. Cardiac findings (aortic root dilation most common). AML risk elevated ~2x. Diagnosis via DNMT3A sequencing or DNA methylation episignature (EpiSign). No TBRS-specific antiseizure guidance.

Indexed context

Tatton-Brown K, Rahman N

dnmt3atbrsgenereviewssurveillanceepisignature

Markdown path

content/research/papers/2022-tbrs-genereviews.md

Findings

Authoritative reference on TBRS. Cardinal features: tall stature, macrocephaly, intellectual disability, subtle facial gestalt. Afebrile seizures ~20%. Cardiac findings (aortic root dilation most common). AML risk elevated ~2x. Diagnosis via DNMT3A sequencing or DNA methylation episignature (EpiSign). No TBRS-specific antiseizure guidance.

Why it may matter for Levi

Clinical-management reference for TBRS. Confirms a robust EpiSign episignature is available as a functional test even when sequencing is uninformative. Surveillance implications for Levi (AML screening, aortic imaging) if TBRS is ever confirmed.

Paper text

Tatton-Brown-Rahman Syndrome — GeneReviews

Tatton-Brown K, Rahman N. — GeneReviews® (2022). https://www.ncbi.nlm.nih.gov/books/NBK581652/

Findings summary

Current authoritative reference on TBRS. Key points from the most recent revision:

  • TBRS is an autosomal dominant overgrowth-intellectual-disability syndrome caused by heterozygous pathogenic variants in DNMT3A. Most cases arise from de novo variants; rare parent-to-child transmission is reported.
  • Cardinal features: tall stature, macrocephaly, intellectual disability (mild to severe), and a distinctive but often subtle facial appearance (low-set heavy horizontal eyebrows, prominent upper central incisors, round face).
  • Additional common features: joint hypermobility, obesity, hypotonia, autism spectrum features, behavioural/psychiatric problems, kyphoscoliosis, afebrile seizures (~20%).
  • Cardiac: aortic root dilation reported most commonly; other structural heart disease, mitral valve prolapse, arrhythmias, and cardiomyopathy are all described.
  • Cancer surveillance: approximately 200% increased relative risk for acute myeloid leukemia has been reported; other tumors have been reported less systematically. Lifetime cancer risk is not yet well quantified.
  • Diagnosis: established in a proband with suggestive findings plus a heterozygous pathogenic DNMT3A variant on molecular testing. Molecular testing approaches include multigene overgrowth / intellectual disability panels, exome sequencing, genome sequencing, and — importantly — genome-wide DNA methylation profiling (EpiSign), which has a robust TBRS episignature.
  • Management: primarily supportive and symptom-driven. Seizures are managed per standard pediatric epilepsy principles; no TBRS-specific antiseizure medication guidance exists. Screening for hematologic malignancy, cardiac anomalies, joint / skeletal issues, and behavioural / psychiatric comorbidity is recommended at each visit.

Relevance to Levi

GeneReviews is the standard reference clinical geneticists use for TBRS. The fact that DNMT3A has a "robust" genome-wide methylation episignature directly supported by clinical validation means an EpiSign / methylation panel could confirm or refute TBRS functionally, even if an underlying DNMT3A variant were beyond the reach of standard germline short-read WGS interpretation.

Surveillance implications if TBRS is confirmed matter for Levi: AML risk screening, cardiac (aortic root) imaging, and structured epilepsy follow-up would all be added to his care plan.

Provenance