Aims and objectives We have reviewed our patients with Congenital Adrenal Hyperplasia (CAH) presenting in Northern Ireland (NI) between 1976 and 2016. Objectives were to determine age, sex and clinical features at presentation; report treatment modalities used including perineal surgery; determine long-term outcomes including final height and surgery in adulthood.

Methods Paediatric and adult case notes were reviewed and a literature search was performed to compare our findings with those previously reported.

Results We report 47 patients from 39 families; 23 patients have transferred to adult services and 22 are currently under paediatric review; 2 have moved away from NI. We found an incidence of 1:23 884 live births. 27 (57%) were female and 20 (43%) male.

20 (43%) presented on the first day of life; 17 (36%) presented with salt wasting crisis and 10 (21%) presented with virilisation in later childhood.

17-OHP levels were high in all patients (20.3 – 2888 nmol/L). Mean plasma sodium was 120 mmol/L (98 – 129 mmol/L) in the salt losing group. 6 (13%) children had urinary steroid examination. Of those tested, all were found to have mutations on CYP21 gene.

100% required glucocorticoid replacement; 87% required mineralocorticoid replacement and 62% required sodium chloride supplementation. 13 (48%) girls had perineal surgery in childhood although we note a trend away from early surgery; 2 have required adrenalectomy in adulthood.

Adult height was found to be –1.5 SDS below mean in both males and females. Our adult patients have had problems with fertility (11%); obesity (4%); psychiatric problems (4%). Of the 23 patients transferred to adult services, 7 (30%) have spent a significant period of time not being followed up and 5 (22%) have been discharged due to poor attendance.

Conclusions Incidence of CAH in NI is less than previously reported in the UK although we have similar ratios of males to females. The vast majority of our children present in the first year of life. We report a trend away from early surgery. Mean final height is impaired. We highlight the need for effective transition to adult services.