Autosomal dominant hereditary sensory neuropathy with chronic cough and gastro-oesophageal reflux: clinical features in two families linked to chromosome 3p22–p24
1 Institute of Clinical Neurosciences, Royal Prince Alfred Hospital and University of Sydney, 2 Neurobiology Laboratory, ANZAC Research Institute, 3 Departments of Molecular Medicine, 4 Respiratory Medicine, Concord Hospital, 5 Canberra Clinical School, Australian National University and University of Sydney, Sydney, 6 Departments of Gastroenterology and Hepatology, 7 Neurology, The Canberra Hospital, 8 Departments of Neurology and 9 Gastroenterology, Princess Alexandra Hospital, 10 Department of Respiratory Medicine, The Mater Adult Hospital, Brisbane, Australia
Correspondence to: Dr Penelope Spring, Department of Neurology, Concord Hospital, Hospital Road Concord, New South Wales, 2139, Australia E-mail: pspring{at}med.usyd.edu.au
Autosomal dominant hereditary sensory neuropathy (HSN I) is a clinically and genetically heterogeneous group of disorders, and in some families it is due to mutations in the serine palmitoyltransferase (SPTLC1) gene. We have characterized two families with HSN I associated with cough and gastro-oesophageal reflux (GOR). From a large Australian family, 27 individuals and from a smaller family, 11 individuals provided clinical information and blood for genetic analysis. Affected individuals had an adult onset of paroxysmal cough, GOR and distal sensory loss. Cough could be triggered by noxious odours or by pressure in the external auditory canal (Arnold's ear–cough reflex). Other features included throat clearing, hoarse voice, cough syncope and sensorineural hearing loss. Neurophysiological and pathological studies demonstrated a sensory axonal neuropathy. Gastric emptying studies were normal, and autonomic function and sweat tests were either normal or showed distal hypohidrosis. Cough was likely to be due to a combination of denervation hypersensitivity of the upper airways and oesophagus, and prominent GOR. Most affected individuals were shown on 24 h ambulatory oesophageal pH monitoring to have multiple episodes of GOR, closely temporally associated with coughing. Hoarse voice was probably attributable to acid-induced laryngeal damage, and there was no evidence of vocal cord palsy. No other cause for cough was found on most respiratory or otorhinological studies. Linkage to chromosome 3p22–p24 has been found in both families, with no evidence of linkage to loci for known HSN I, autosomal dominant hereditary motor and sensory neuropathy, hereditary GOR or triple A syndrome. These families represent a genetically novel variant of HSN I, with a distinctive cough owing to involvement of the upper aerodigestive tract.
Key Words: skin biopsy; neuropathy; hereditary neuropathy; epidermal nerve; autonomic dysfunction
Abbreviations: ANA = anti-nuclear antibody; BAERs = brainstem auditory evoked responses; CMAP = compound motor action potential; CMT = Charcot–Marie–Tooth; ENA = extractable nuclear antigens; ENFD = epidermal nerve fibre density; ENT = ear nose and throat; FEESST = fibreoptic endoscopic evaluation of swallowing and sensory testing; GIT = gastrointestinal tract; GOR = gastro-oesophageal reflux; HMSN = hereditary motor and sensory neuropathy; HSAN = hereditary sensory and autonomic neuropathy; HSN = hereditary sensory neuropathy; LOS = lower oesophageal sphincter; NCS = nerve conduction studies; NGF = nerve growth factor; QST = quantitative sensory testing
Received December 21, 2004. Revised August 31, 2005. Accepted September 2, 2005.