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A real natural history
How features evolve across infancy, childhood, adolescence, adulthood. With cases identified only since 2019, the longest follow-ups are still short.
A hand-curated bibliography of peer-reviewed work on DLL1, NEDBAS, SCDO7, and terminal 6q27 deletions — with direct links to the source. Last verified August 2026.
The Delta gene is identified in Drosophila as a controller of which embryonic cells become neurons. The Notch pathway as we know it begins to take shape.
The mammalian Delta-like ligands — DLL1, DLL3, DLL4 — are identified and mapped. DLL1 is localised to 6q27.
Targeted disruption of Dll1 in mice produces vertebral patterning defects and disrupted neurogenesis — foreshadowing the human disorder.
An international collaboration identifies heterozygous DLL1 variants in patients with neurodevelopmental disorder, brain abnormalities, and vertebral malformations. OMIM #618709 is established.
Additional families and case reports broaden the picture: more vertebral involvement in some, more autism features in others, less severe presentations alongside the originally described ones.
A community is taking shape around the gene. Patient registries, natural-history studies, and functional work on specific variants are now possible — and largely propelled by families.
Original disease description and authoritative gene-level resources.
Fischer-Zirnsak B, Segebrecht L, Schubach M, et al.
First description of NEDBAS: 15 individuals from 12 families with heterozygous DLL1 variants — established the dominant haploinsufficiency mechanism and the OMIM #618709 phenotype entry.
ClinGen Brain Malformation GCEP
Independent expert review classified the DLL1–NEDBAS association as Definitive — the highest evidence tier for a gene-disease relationship.
OMIM curators
Canonical gene entry: 6q27, 11 exons, encodes a 723-aa type-I transmembrane DSL-family ligand for NOTCH receptors.
OMIM curators
Phenotype entry summarising the dominant DLL1-haploinsufficiency disorder: developmental delay, intellectual disability, brain MRI abnormalities, autistic features, seizures, and variable scoliosis.
NCBI ClinVar
Live catalog of DLL1 variants submitted by clinical and research labs worldwide, with classifications and supporting evidence — the place to deposit your own variant.
gnomAD consortium
Population-level evidence of constraint: DLL1 has high pLI / low LOEUF, consistent with intolerance to loss-of-function variation — supporting the haploinsufficiency mechanism.
Animal models and molecular work supporting Notch-pathway disruption.
Aguilar-Hernández L, et al.
Mouse model showing Dll1+/- animals develop the brain abnormalities and behavioural phenotypes seen in patients — provides the first functional evidence supporting haploinsufficiency.
Vertebral segmentation literature relevant to the rare recessive form.
OMIM curators
Catalog entry establishing SCDO7 as a distinct autosomal recessive condition caused by biallelic DLL1 missense variants — to date documented in a single consanguineous family.
Turnpenny PD, Sloman M, Dunwoodie S
Authoritative clinical synopsis of recessive SCDO including DLL3, MESP2, LFNG, HES7, TBX6, RIPPLY2, and DLL1 (SCDO7) — diagnostic criteria, surveillance, and management.
Umair M, Younus M, Shafiq S, Nayab A, Alfadhel M
Concise review covering all known SCDO subtypes including the DLL1-associated SCDO7 — useful primer for clinicians evaluating vertebral segmentation defects.
Sparrow DB, Chapman G, Wouters MA, Whittock NV, Ellard S, Fatkin D, Turnpenny PD, Kusumi K, Sillence D, Dunwoodie SL
Foundational paper establishing Notch-pathway disruption (LFNG, and by extension DLL1/DLL3) as a cause of spondylocostal dysostosis — context for SCDO7.
Cytogenetic and prenatal series where DLL1 is part of a larger deletion.
Engwerda A, et al.
Largest cohort to date of terminal 6q deletions — demonstrates that DLL1 loss is a major driver of neurodevelopmental features regardless of additional co-deleted genes.
Multiple authors
Retrospective analysis linking DLL1 haploinsufficiency to specific prenatal brain findings (cerebellar hypoplasia, ventriculomegaly) detectable on fetal imaging.
Peddibhotla S, Khalifa M, Probst FJ, Stein J, Harris LL, Kearney DL, Belmont JW, Cheung SW, Scott DA
Earlier cytogenetic series of terminal 6q deletions delineating the recurrent neurodevelopmental phenotype that later Engwerda et al. attributed largely to DLL1 loss.
The DLL1 literature is moving quickly. If you have authored or read a paper that belongs here, please tell us.
Send it to us →The open scientific questions whose answers would most change life for families with a DLL1 result in hand.
How features evolve across infancy, childhood, adolescence, adulthood. With cases identified only since 2019, the longest follow-ups are still short.
Do specific variants — DSL-domain missense versus whole-gene deletion — produce different phenotypic profiles? With more cases collected, this becomes answerable.
Two individuals with the same DLL1 variant can present very differently. Identifying genetic modifiers — variants elsewhere in the genome that turn the volume up or down — is open and important.
Cell-based and model-organism studies that test whether a patient's variant actually impairs Notch signalling, and how much. This is how VUS variants get reclassified.
A consented, longitudinal registry that pools clinical and genetic information across families gives every single case more scientific value.
Notch signalling is one of the most therapeutically targeted pathways in biology — though largely in cancer. Whether any of that pharmacology eventually informs treatment of haploinsufficiency disorders is a long-horizon but real question.
This makes the variant visible to every clinician and researcher who looks up the gene in the future. Many labs do this automatically; it doesn't hurt to ask.
These studies turn a scattered group of case reports into something a clinical guideline can be written from. Voluntary, confidential, takes 10–15 minutes.
This not only helps your family — it helps the laboratory's interpretation database stay current for everyone else.
One of the things this site exists for is to help families find researchers, and researchers find families. The connection is often the bottleneck.
A short list of trusted, generally-free resources for rare neurodevelopmental disorders. None is DLL1-specific yet — but the foundation is working on changing that.