Endocrine Abstracts

Adrenoleukodystrophy (ALD) is an X-linked, widely heterogeneous, neurodegenerative disorder of peroxisomal metabolism characterised by the accumulation of very-long-chain fatty acids (VLCFA). A mutation in the ABCD1 gene is responsible. ALD has both a neurological and an endocrine interface as VLCFA deposit in the central and peripheral nervous system as well as the adrenal cortex and testis. ALD can present in childhood with a cerebral form or later in life as an adrenomyeloneuropathy type. ALD can also present with isolated adrenocortical failure. There is no clinical correlation between the severity of the neurological presentation and the endocrine manifestations. We describe the case of a 40 year old gentleman who presented with progressive spastic paraparesis following a road traffic accident. Neurological imaging did not reveal any structural or demyelinating abnormalities. After extensive investigations, he was noted to have elevated levels of VLCFA and genetic tests confirmed an ABCD1 gene mutation, hence confirming a diagnosis of ALD. An endocrine work-up was carried out. He described fatigue and minimal postural symptoms. On examination, he was not obviously hyperpigmented and demonstrated no postural blood pressure changes. Other tests revealed normal sodium and potassium levels, an aldosterone level of 180 pmol/L (100–800) and a renin level of 78.8 mu/L (12.9–33.7). A short synacthen test revealed a normal cortisol response to ACTH with a 30 minute cortisol of 603. This case highlights the importance of carefully screening all ALD cases for adrenocortical involvement; this will prevent catastrophic Addisonian crises in periods of stress. Elevated renin levels indicates deposition of VLCFA in the zona glomerulosa which can herald impending adrenal cortex failure further during the course of the disease; hence the need for regular adrenal reserve assessments. Likewise, male patients diagnosed with idiopathic or negative adrenal antibody Addison’s disease should have VLCFA measured to exclude ALD.