An 18-year-old woman presenting with profound macrocytic anemia was found to have antibody-confirmed pernicious anemia—and a constellation of findings fulfilling all six major clinical criteria for Bardet–Biedl syndrome.
Imran and Ali describe a Pakistani woman from a consanguineous family who presented with four months of progressive fatigue, weakness, pallor, and exertional dyspnea. Her hemoglobin was 4.7 g/dL, with macrocytosis, vitamin B12 deficiency, macro-ovalocytes, and hypersegmented neutrophils. Positive anti-intrinsic factor and anti-parietal cell antibodies supported the diagnosis of autoimmune pernicious anemia.
A more detailed history revealed childhood-onset retinal dystrophy progressing to blindness, postaxial polydactyly, obesity, developmental delay, primary amenorrhea, diabetes mellitus, bilateral small kidneys, albuminuria, and a similarly affected sibling. Together, these findings fulfilled all six major and two minor clinical criteria for Bardet–Biedl syndrome.
Molecular confirmation was unavailable because of financial and logistical limitations. The case therefore illustrates the continuing value of established clinical diagnostic criteria in settings where genetic testing cannot readily be obtained.
The co-occurrence of Bardet–Biedl syndrome and autoimmune pernicious anemia is rare. Emerging evidence suggests that ciliary dysfunction may influence immune regulation, but this single case cannot establish a causal relationship. The association remains biologically plausible and hypothesis-generating.
The patient improved following packed red-cell transfusion and intramuscular cyanocobalamin and was discharged on lifelong vitamin B12 replacement with multidisciplinary follow-up.
Clinical Take-Home Message
In patients with Bardet–Biedl syndrome or a compatible ciliopathy phenotype, macrocytic anemia and vitamin B12 deficiency should prompt evaluation for pernicious anemia rather than being attributed automatically to nutritional deficiency or chronic disease. Early recognition and treatment may prevent irreversible neurologic complications.
Reference
Imran J, Ali M. Autoimmune pernicious anemia in clinically diagnosed Bardet–Biedl syndrome: a case report and brief literature review. Journal of Medical Case Reports. 2026.
https://doi.org/10.1186/s13256-026-06593-9