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IEMbase 0774: SAMHD1-related SAMS association and AGS5

Scope

Field Value
IEMbase ID 774
Nosology 9.1.06.02
Nosology code IEM0031
Gene SAMHD1
External IDs OMIM:612952; ORPHA:481662
Generated mapping AMBIGUOUS; Aicardi_Goutieres_Syndrome and subtype Aicardi-Goutieres syndrome 5
Candidate DisMech targets Aicardi_Goutieres_Syndrome.yaml subtype Aicardi-Goutieres syndrome 5
Review date 2026-07-08

IEMbase phenotype signal

IEMbase labels this autosomal recessive record as SAMHD1-related stenosis, aneurysm, moyamoya, and stroke association, with alternate name Aicardi-Goutieres syndrome type 5. The phenotype signal includes the standard AGS neurologic and inflammatory pattern plus an explicit cerebrovascular row: cognitive dysfunction, seizures, feeding difficulty, hepatosplenomegaly, sterile pyrexia, chilblains, cerebral atrophy, intracerebral calcifications, leukodystrophy, microcephaly, dystonia, exaggerated startle, irritability, sleep disturbance, spasticity, and cerebrovascular disease including stenosis, aneurysm, moyamoya-like disease, and stroke. Laboratory rows include CSF neopterin, CSF lymphocytes, CSF interferon-alpha, interferon-stimulated gene signature, autoantibodies, transaminases, platelets, and neonatal C26:0 fatty acid.

DisMech phenotype coverage

Aicardi_Goutieres_Syndrome.yaml has an explicit Aicardi-Goutieres syndrome 5 subtype with SAMHD1 and MONDO:0013059. The local AGS disease-level phenotype set covers the shared brain, movement, neurodevelopmental, inflammatory, cutaneous, and laboratory findings. It also has a pathophysiology node for systemic interferon-mediated inflammation and vasculopathy whose description specifically mentions SAMHD1-associated intracranial vasculopathy.

Concordance and completeness

Judgement: exact subtype coverage with an important cerebrovascular completeness prompt.

The gene, OMIM identity, inheritance, AGS5 subtype, and type I interferonopathy model are concordant. IEMbase is more explicit than the current phenotype list for SAMHD1-related SAMS: stenosis, aneurysm, moyamoya-like disease, and stroke are visible as source phenotypes, while DisMech currently captures this mainly in prose/pathophysiology plus more general hemiplegia/hemiparesis and vasculopathy context.

Curation actions

  • Treat Aicardi_Goutieres_Syndrome.yaml subtype Aicardi-Goutieres syndrome 5 as exact local coverage for IEMbase 0774.
  • Consider adding explicit SAMHD1-associated intracranial stenosis, aneurysm, moyamoya, or stroke phenotype rows if supported by existing local evidence.
  • Preserve CSF neopterin, startle response, feeding difficulty, sleep disturbance, and platelet rows as broader AGS completeness prompts.