Permanent neonatal diabetes: different aetiology in Arabs compared to Europeans

Objective Mutations in the KCNJ11 and ABCC8 genes that encode the pancreatic K-ATP channel are the commonest cause of permanent neonatal diabetes mellitus (PNDM). The authors aimed to define the genetic causes of PNDM in a large cohort of Arab patients and compare them with a British cohort tested in the same laboratory. Design Retrospective observational study. Setting International genetics centre. Patients Arab and British subjects with PNDM who were referred for genetic testing over the same period. Intervention Comparison of genotypes and phenotypes between the two cohorts. Main outcome measures The aetiology and phenotype of PNDM in an Arab compared to a British cohort. Results 88 Arab and 77 British probands were referred between 2006 and 2011, inclusive. Consanguinity was higher among Arabs (63.6% vs 10.4%) and a higher percentage had a genetic diagnosis compared to the British cohort (63.6% vs 41.6%). Recessive EIF2AK3 gene mutations were the commonest cause of PNDM in the Arab cohort (22.7%) followed by INS (12.5%), and KCNJ11 and GCK (5.7% each), whereas K-ATP channel mutations were the commonest cause (29.9%) in the British cohort. In 37.5% of Arab patients PNDM was part of a genetic syndrome compared to 7.8% of the British cohort. Conclusion PNDM in the Arab population has a different genetic spectrum compared to British patients where K-ATP channel mutations are the commonest cause, similar to other European populations. In Arabs, PNDM is more likely to be part of a recessively inherited syndrome, possibly due to the higher rate of consanguinity.