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FAM120B – Type 1 Diabetes Mellitus

The current body of evidence does not support an association between FAM120B and type 1 diabetes mellitus. Two multi‑patient studies extensively evaluated the IDDM8 region on chromosome 6q27, including FAM120B, but failed to demonstrate any significant genetic association. One study, which genotyped up to 83 polymorphisms in as many as 725 T1D families (PMID:15850778), provided no evidence to support an association with the disease. Similarly, a fine‑mapping study in an autoimmune cohort that included both type 1 diabetes mellitus and rheumatoid arthritis cases (PMID:16945141) also did not detect any meaningful association signals.

In summary, neither case reports nor segregation data substantiate a role for FAM120B in the pathogenesis of type 1 diabetes mellitus. In addition, functional assessments using model systems have not revealed a mechanism by which FAM120B might contribute to disease susceptibility. Overall, the genetic and experimental findings strongly refute a clinically actionable association, thereby limiting the diagnostic utility of FAM120B testing for type 1 diabetes mellitus.

References

  • Biochemical and biophysical research communications • 2005 • No evidence for association of the TATA-box binding protein glutamine repeat sequence or the flanking chromosome 6q27 region with type 1 diabetes PMID:15850778
  • Arthritis research & therapy • 2006 • Fine mapping of genes within the IDDM8 region in rheumatoid arthritis PMID:16945141

Evidence Based Scoring (AI generated)

Gene–Disease Association

Refuted

Large-scale association studies in up to 725 T1D families (PMID:15850778) and additional fine mapping in autoimmune cohorts (PMID:16945141) have failed to identify any variant burden, segregation, or recurrent mutations in FAM120B to support its involvement in type 1 diabetes mellitus.

Genetic Evidence

Disputed

Case‑control analyses and the lack of familial segregation data provide no convincing genetic evidence that FAM120B contributes to type 1 diabetes mellitus.

Functional Evidence

Limited

Experimental studies on FAM120B have not demonstrated a mechanistic link to type 1 diabetes mellitus, and the functional assays fail to recapitulate any relevant aspects of disease pathogenesis.