Phagocyte Defects
Gene: SEPTIN6
PMID 34677878 and PMID 42088107 report three patients from two independent families with X‑linked severe congenital neutropenia, B‑cell aplasia and variable T‑cell lymphopenia caused by stop‑loss variants in SEPTIN6; one is inherited from unaffected mother (two affected sibs) and the other is de novo.
Functional studies in PMID 34677878: patient skin fibroblast-derived induced pluripotent stem cells (iPSCs) produced reduced myeloid colonies, particularly of the granulocyte lineage. CRISPR/Cas9 knock-in of the patient's mutation or complete knock-out of SEPT6 was not tolerated in non-patient-derived iPSCs or human myeloid cell lines, but SEPT6 knock-out was successful in an erythroid cell line and resulting clones revealed a propensity to multinucleation. In silico analysis predicted that the mutated protein hinders the dimerization of SEPT6 coiled-coils in both parallel and antiparallel arrangements, which could in turn impair filament formation.
Sources: LiteratureCreated: 19 Jun 2026, 1:20 a.m.
Mode of inheritance
X-LINKED: hemizygous mutation in males, biallelic mutations in females
Phenotypes
Inborn error of immunity, MONDO:0003778, SEPTIN6-related
Publications
Gene: septin6 has been classified as Amber List (Moderate Evidence).
Mode of inheritance for gene: SEPTIN6 was changed from X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males) to X-LINKED: hemizygous mutation in males, biallelic mutations in females
gene: SEPTIN6 was added gene: SEPTIN6 was added to Phagocyte Defects. Sources: Expert Review Amber,Literature Mode of inheritance for gene: SEPTIN6 was set to X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males) Publications for gene: SEPTIN6 were set to 42088107; 34677878 Phenotypes for gene: SEPTIN6 were set to Inborn error of immunity, MONDO:0003778, SEPTIN6-related