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SLC2A2 – Permanent Neonatal Diabetes Mellitus

Biallelic loss-of-function variants in SLC2A2 have been identified as a rare cause of permanent neonatal diabetes mellitus (PNDM) in highly consanguineous populations. In a Qatari cohort of nine patients with PNDM, whole‐genome sequencing revealed seven distinct pathogenic variants across six genes, including SLC2A2 in one proband, corresponding to an incidence of 1:22 938 live births ([PMID:31441606]). In northwest Saudi Arabia, 17 PNDM patients from 11 consanguineous families were studied; sequencing of 9 genes uncovered one novel homozygous SLC2A2 variant among six disease-causing alleles, with an incidence of 1:21 196 live births ([PMID:22060631]).

SLC2A2-related PNDM follows an autosomal recessive inheritance pattern, with at least two unrelated probands reported. One homozygous nonsense mutation, c.901C>T (p.Trp420Ter), has been modeled in patient-derived iPSCs, demonstrating complete GLUT2 deficiency and defective glucose release in β-cell precursors ([PMID:34171785]). GLUT2 is essential for glucose‐stimulated insulin secretion, and its absence impairs neonatal glycemic homeostasis.

Clinical Validity Assessment

  • Overall ClinGen classification: Limited
  • Rationale: 2 unrelated probands with biallelic SLC2A2 variants in high-consanguinity cohorts; no segregation beyond index cases; limited PNDM‐specific functional studies.

Key Take-Home Message

SLC2A2 should be included in genetic testing panels for autosomal recessive PNDM, particularly in consanguineous populations, although further segregation and functional data are required to establish definitive clinical validity.

References

  • Molecular genetics & genomic medicine • 2019 • The clinical and genetic characteristics of permanent neonatal diabetes (PNDM) in the state of Qatar. PMID:31441606
  • Pediatric diabetes • 2012 • Incidence, genetics, and clinical phenotype of permanent neonatal diabetes mellitus in northwest Saudi Arabia. PMID:22060631
  • Stem cell research • 2021 • An induced pluripotent stem cell line derived from a patient with neonatal diabetes and Fanconi-Bickel syndrome caused by a homozygous mutation in the SLC2A2 gene. PMID:34171785

Evidence Based Scoring (AI generated)

Gene–Disease Association

Limited

2 probands with biallelic variants in consanguineous cohorts; no extended segregation; minimal PNDM-specific functional confirmation

Genetic Evidence

Limited

Biallelic SLC2A2 variants in two unrelated probands; autosomal recessive pattern; no segregation beyond index cases

Functional Evidence

Limited

iPSC modeling shows GLUT2 deficiency impairs glucose release, but PNDM-specific rescue/segregation data are lacking