Endocrine Abstracts

Background: Kearns-Sayre syndrome is a rare mitochondrial disorder which can manifest as numerous endocrinological abnormalities. The case we are presenting shows the importance of consideration of such in children presenting with primary hypoparathyroidism with other multi-system involvement.

Case presentation: An 8 year old boy presented with a longstanding history of lethargy, weakness, poor appetite and growth concerns. He was seen in paediatric clinic at the age of 6 in view of faltering growth with normal investigations at the time. On presentation his height was 116 cm (1st centile), weight 18 kg (0.12 centile) with mid-parental height at 60th centile. He had bilateral ptosis, strabismus, and injected conjunctiva. Neurological examination was significant for ataxia and dysmetria. Investigations revealed high lactate, hypocalcaemia, hypomagnesaemia and hypokalaemia with normal glucose and infection markers. Further investigations showed low PTH which confirmed the diagnosis of primary hypoparathyroidism, as well as renal tubulopathy. He had normal TFT’s, Hb1AC, random cortisol and aldosterone levels. Ophthalmology review was significant for pigmented retinopathy and external ophthalmoplegia. He was found to have moderate sensorineural hearing loss. He had normal metabolic and autoimmune screen, but raised protein and lactate on CSF. MRI brain was suggestive of metabolic encephalopathy. Mitochondrial disorder was suspected and genetics test showed large scale mtDNA deletion which had confirmed the diagnosis of KSS. His management involved regular follow up in endocrinology, cardiology and renal clinics, with OT/physio input, and regular monitoring of PTH, TFT and adrenal axis, as well as supplementation with calcium, vitamin D, magnesium and co-enzyme-10.

Conclusion: KSS is a rare mitochondrial multisystem disorder defined by the triad of onset before age 20, pigmentary retinopathy and progressive external ophthalmoplegia with at least one of the following: cardiac conduction block, high CSF protein levels, or cerebellar ataxia. Other features include endocrine involvement, hearing loss, dementia, and myopathy. Endocrine involvement includes short stature, GH deficiency, DM, hypothyroidism, adrenal insufficiency or primary hypoparathyroidism as presented here. Management is supportive with hormonal replacement therapy as required, cardiac pacemaker in case of conduction abnormalities, corrective surgery for eye abnormalities, cochlear implants and co-enzyme 10 (ubiquinone). Prognosis is guarded.