Hereditary Autonomic Neuropathy of the Oral Cavity and its Management

Hereditary sensory and autonomic neuropathies (HSAN) are rare genetic disorders that often manifest during childhood in the form of absence of pain sensation or self-mutilation. Patients often present significant oral self-mutilation manifestations, and biting of the lips, tongue, and cheeks have been frequently reported. This case report describes a case of hereditary sensory and autonomic neuropathy with oral and cutaneous ulcers. Our patient was a 14-month-old girl with the chief complaint of a tongue ulcer, as stated by her parents, who were referred to our private dental clinic. Clinical examination revealed severe ulcers due to biting (Riga-Fede disease) on the ventral surface of the tongue and superficial ulcers on the dorsal surface of the tongue caused by the anterior maxillary teeth, along with some sores on fingers. The parents were healthy, with no congenital disease or familial history of a similar condition. The electrodiagnostic test revealed the absence of sensory nerve action potential response. However, the electromyographic findings and the compound muscle action potential of the tibial and ulnar nerves were normal. Oral ulcers such as trauma to the lips and tongue, and self-mutilation trauma to the fingers can be used for early detection of Hereditary sensory and autonomic neuropathies. A multidisciplinary approach involving a professional dental team and a regular treatment protocol are imperative to prevent complications of Hereditary sensory and autonomic neuropathies.

Founder mutation in IKBKAP gene causes vestibular impairment in familial dysautonomia

OBJECTIVE

To assess vestibular function in patients with familial dysautonomia (FD), a hereditary sensory and autonomic neuropathy - caused by a mutation in the IKBKAP gene (c.2204 + 6 T>C) - and characterized by marked gait ataxia.

METHODS

Cervical and vestibular evoked myogenic potentials (cVEMPs and oVEMPs) were recorded from the sternocleidomastoid (SCM) and extraocular muscles in 14 homozygous patients, 2 heterozygous patients, and 15 healthy controls during percussion of the forehead.

RESULTS

cVEMP and oVEMP amplitudes were significantly lower, and peak latencies significantly delayed, in the FD patients. There were no differences in overall EMG during attempted maximal voluntary contractions of the SCM muscle, suggesting intact efferent function. The two heterozygotes with a minor haplotype missense (R696P) mutation in exon 19 of the IKBKAP gene had cVEMP responses less affected than the homozygous.

CONCLUSIONS

The founder mutation in the IKBKAP gene affects the development of vestibular afferent pathways, leading to attenuated cVEMPs.

SIGNIFICANCE

Vestibular abnormalities may contribute to the gait ataxia in FD.

Oral manifestations, dental management, and a rare homozygous mutation of the PRDM12 gene in a boy with hereditary sensory and autonomic neuropathy type VIII: a case report and review of the literature

BACKGROUND

Hereditary sensory and autonomic neuropathy type VIII is a rare autosomal recessive inherited disorder. Chen et al. recently identified the causative gene and characterized biallelic mutations in the PR domain-containing protein 12 gene, which plays a role in the development of pain-sensing nerve cells. Our patient's family was included in Chen and colleagues' study. We performed a literature review of the PubMed library (January 1985 to December 2016) on hereditary sensory and autonomic neuropathy type I to VIII genetic disorders and their orofacial manifestations. This case report is the first to describe the oral manifestations, and their treatment, of the recently discovered hereditary sensory and autonomic neuropathy type VIII in the medical and dental literature.

CASE PRESENTATION

We report on the oral manifestations and dental management of an 8-month-old white boy with hereditary sensory and autonomic neuropathy-VIII over a period of 16 years. Our patient was homozygous for a mutation of PR domain-containing protein 12 gene and was characterized by insensitivity to pain and thermal stimuli, self-mutilation behavior, reduced sweat and tear production, absence of corneal reflexes, and multiple skin and bone infections. Oral manifestations included premature loss of teeth, associated with dental traumata and self-mutilation, severe soft tissue injuries, dental caries and submucosal abscesses, hypomineralization of primary teeth, and mandibular osteomyelitis.

CONCLUSIONS

The lack of scientific knowledge on hereditary sensory and autonomic neuropathy due to the rarity of the disease often results in a delay in diagnosis, which is of substantial importance for the prevention of many complications and symptoms. Interdisciplinary work of specialized medical and dental teams and development of a standardized treatment protocols are essential for the management of the disease. There are many knowledge gaps concerning the management of patients with hereditary sensory and autonomic neuropathy-VIII, therefore more research on an international basis is needed.

The familial dysautonomia disease gene IKBKAP is required in the developing and adult mouse central nervous system

Hereditary sensory and autonomic neuropathies (HSANs) are a genetically and clinically diverse group of disorders defined by peripheral nervous system (PNS) dysfunction. HSAN type III, known as familial dysautonomia (FD), results from a single base mutation in the gene IKBKAP that encodes a scaffolding unit (ELP1) for a multi-subunit complex known as Elongator. Since mutations in other Elongator subunits (ELP2 to ELP4) are associated with central nervous system (CNS) disorders, the goal of this study was to investigate a potential requirement for Ikbkap in the CNS of mice. The sensory and autonomic pathophysiology of FD is fatal, with the majority of patients dying by age 40. While signs and pathology of FD have been noted in the CNS, the clinical and research focus has been on the sensory and autonomic dysfunction, and no genetic model studies have investigated the requirement for Ikbkap in the CNS. Here, we report, using a novel mouse line in which Ikbkap is deleted solely in the nervous system, that not only is Ikbkap widely expressed in the embryonic and adult CNS, but its deletion perturbs both the development of cortical neurons and their survival in adulthood. Primary cilia in embryonic cortical apical progenitors and motile cilia in adult ependymal cells are reduced in number and disorganized. Furthermore, we report that, in the adult CNS, both autonomic and non-autonomic neuronal populations require Ikbkap for survival, including spinal motor and cortical neurons. In addition, the mice developed kyphoscoliosis, an FD hallmark, indicating its neuropathic etiology. Ultimately, these perturbations manifest in a developmental and progressive neurodegenerative condition that includes impairments in learning and memory. Collectively, these data reveal an essential function for Ikbkap that extends beyond the peripheral nervous system to CNS development and function. With the identification of discrete CNS cell types and structures that depend on Ikbkap, novel strategies to thwart the progressive demise of CNS neurons in FD can be developed.

Summary:Ikbkap is essential for normal CNS development, neuronal survival and behavior, adding to our understanding of the role of the Elongator complex in the mammalian CNS.

Charcot spinal arthropathy in patients with congenital insensitivity to pain: a report of two cases and review of the literature

Charcot spine, or neuropathic spinal arthropathy, involves the progressive destruction of the spinal joint due to the lack of normal protective sensations and proprioception. A rare cause of Charcot spine is congenital insensitivity to pain, which is an absent or abnormal response to painful stimuli. There are few case reports describing this condition, and long-term follow-up data are limited. The presentation and treatment of two patients with Charcot spine secondary to congenital insensitivity to pain are described. Both cases were characterized by lumbar involvement and were treated with circumferential decompression and an extended lumbo-pelvic fusion construct. The cases described here demonstrate stable neurological status at 1.5 and 5 years follow-up. Patient characteristics, pre- and post-operative imaging, operative approach, and outcomes are described. The literature regarding this rare condition is also reviewed, with an emphasis on operative management and outcomes. Surgical management is traditionally complicated by a high rate of hardware failure and adjacent segment degeneration. The current review highlights the importance of prompt and aggressive management following diagnosis of Charcot spine, as well as extended follow-up.

Hereditary neuropathies: An update

Hereditary neuropathies are the most common inherited neuromuscular diseases. Charcot-Marie-Tooth (CMT) disease represents the most common form with an average prevalence ranging from 1/2500 to 1/1200, depending on the studies. To date and with the advances of the latest generation sequencing, more than 80 genes have been identified. Although the common clinical phenotype comprises a progressive distal muscle weakness and sensory loss, foot deformities and decreased or absent tendon reflexes, clinical and electrophysiological phenotypes exhibit great variability. Moreover, atypical phenotypes are arising, overlapping with spastic paraplegia, hereditary sensory neuropathies or amyotrophic lateral sclerosis. The causative genes are involved in various biological processes such as myelin development and maintenance, biosynthesis and degradation of proteins, neuronal structural maintenance, axonal transport, endocytosis, membrane dynamics, ion-channel function and the mitochondrial network. An accurate genetic diagnosis is important for appropriate genetic counselling and treatment options. Therapeutic advances, particularly small interfering RNA therapy, are encouraging in hereditary transthyretin amyloid neuropathy.

Oral manifestations and prosthetic rehabilitation in hereditary sensory and autonomic neuropathy (HSAN)type IV: a case report

Hereditary sensory and autonomic neuropathies (HSAN) are rare genetic syndromes of unknown etiology. They are seen in early childhood and are categorized into six different types by their symptoms. HSAN type 4 demonstrates autosomal recessive transmission pattern, with such major characteristics as loss of sense of pain, self-mutilation, anhydrosis and mental retardation. Sympathetic innervations are deficient despite the existence of sweat glands. Sufferers are hypotonic without any tendon reflexes, and neuro-motor development is retarded. In some cases tactile sensation and vibration may be intact. Biting injuries due to lack of pain sensation cause laceration, ulceration and scarring of the tongue, lips and other parts of oral mucosa. Tooth luxation and severe dental attrition have been observed. This case report presents oral and dental findings, surgical treatments and prosthetic rehabilitation of an 11- year-old boy with HSAN type 4.

Mother-induced hypertension in familial dysautonomia

Here we report the case of a patient with familial dysautonomia (a genetic form of afferent baroreflex failure), who had severe hypertension (230/149 mmHg) induced by the stress of his mother taking his blood pressure. His hypertension subsided when he learnt to measure his blood pressure without his mother's involvement. The case highlights how the reaction to maternal stress becomes amplified when catecholamine release is no longer under baroreflex control.