Dental and oral findings in patients with familial dysautonomia

Quantitative magnetic resonance evaluation of the trigeminal nerve in familial dysautonomia

PURPOSE

Familial dysautonomia (FD) is a rare autosomal recessive disease that affects the development of sensory and autonomic neurons, including those in the cranial nerves. We aimed to determine whether conventional brain magnetic resonance imaging (MRI) could detect morphologic changes in the trigeminal nerves of these patients.

METHODS

Cross-sectional analysis of brain MRI of patients with genetically confirmed FD and age- and sex-matched controls. High-resolution 3D gradient-echo T1-weighted sequences were used to obtain measurements of the cisternal segment of the trigeminal nerves. Measurements were obtained using a two-reader consensus.

RESULTS

Twenty pairs of trigeminal nerves were assessed in ten patients with FD and ten matched controls. The median (interquartile range) cross-sectional area of the trigeminal nerves in patients with FD was 3.5 (2.1) mm², compared to 5.9 (2.0) mm² in controls (P < 0.001). No association between trigeminal nerve area and age was found in patients or controls.

CONCLUSIONS

Using conventional MRI, the caliber of the trigeminal nerves was significantly reduced bilaterally in patients with FD compared to controls, a finding that appears to be highly characteristic of this disorder. The lack of correlation between age and trigeminal nerve size supports arrested neuronal development rather than progressive atrophy.

Respiratory care in familial dysautonomia: Systematic review and expert consensus recommendations

BACKGROUND

Familial dysautonomia (Riley-Day syndrome, hereditary sensory autonomic neuropathy type-III) is a rare genetic disease caused by impaired development of sensory and afferent autonomic nerves. As a consequence, patients develop neurogenic dysphagia with frequent aspiration, chronic lung disease, and chemoreflex failure leading to severe sleep disordered breathing. The purpose of these guidelines is to provide recommendations for the diagnosis and treatment of respiratory disorders in familial dysautonomia.

METHODS

We performed a systematic review to summarize the evidence related to our questions. When evidence was not sufficient, we used data from the New York University Familial Dysautonomia Patient Registry, a database containing ongoing prospective comprehensive clinical data from 670 cases. The evidence was summarized and discussed by a multidisciplinary panel of experts. Evidence-based and expert recommendations were then formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Recommendations were formulated for or against specific diagnostic tests and clinical interventions. Diagnostic tests reviewed included radiological evaluation, dysphagia evaluation, gastroesophageal evaluation, bronchoscopy and bronchoalveolar lavage, pulmonary function tests, laryngoscopy and polysomnography. Clinical interventions and therapies reviewed included prevention and management of aspiration, airway mucus clearance and chest physical therapy, viral respiratory infections, precautions during high altitude or air-flight travel, non-invasive ventilation during sleep, antibiotic therapy, steroid therapy, oxygen therapy, gastrostomy tube placement, Nissen fundoplication surgery, scoliosis surgery, tracheostomy and lung lobectomy.

CONCLUSIONS

Expert recommendations for the diagnosis and management of respiratory disease in patients with familial dysautonomia are provided. Frequent reassessment and updating will be needed.

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.

Brainstem reflexes in patients with familial dysautonomia

OBJECTIVE

Several distinctive clinical features of patients with familial dysautonomia (FD) including dysarthria and dysphagia suggest a developmental defect in brainstem reflexes. Our aim was to characterize the neurophysiological profile of brainstem reflexes in these patients.

METHODS

We studied the function of sensory and motor trigeminal tracts in 28 patients with FD. All were homozygous for the common mutation in the IKAP gene. Each underwent a battery of electrophysiological tests including; blink reflexes, jaw jerk reflex, masseter silent periods and direct stimulation of the facial nerve. Responses were compared with 25 age-matched healthy controls.

RESULTS

All patients had significantly prolonged latencies and decreased amplitudes of all examined brainstem reflexes. Similar abnormalities were seen in the early and late components. In contrast, direct stimulation of the facial nerve revealed relative preservation of motor responses.

CONCLUSIONS

The brainstem reflex abnormalities in FD are best explained by impairment of the afferent and central pathways. A reduction in the number and/or excitability of trigeminal sensory axons is likely the main problem.

SIGNIFICANCE

These findings add further evidence to the concept that congenital mutations of the elongator-1 protein (or IKAP) affect the development of afferent neurons including those carrying information for the brainstem reflex pathways.

A review of the oro-dento-facial characteristics of hereditary sensory and autonomic neuropathy type III (familial dysautonomia)

The oro-dento-facial features and dysfunction of children with hereditary sensory and autonomic neuropathy type III, known as familial dysautonomia or Riley-Day syndrome, was first described in the scientific literature in 1949. They include dental trauma; dental and soft tissue self-mutilation; normal dental age; normal sequence and timing of eruption and exfoliation of teeth; smaller tooth size; different and disproportional tooth components; normal alveolar bone height; small jaws, mild crowding, and malocclusions. These persons have craniofacial morphology that is different from accepted norms but they resemble norms of their ethnic origin. The subjects can have gray, pale, shiny faces with an asymmetric suffering expression; frontal bossing, with eventual hypertelorism and narrow lips; a low-caries rate; drooling, and hypersalivation. They can have changes in salivary composition and content, which influences plaque and calculus and increases the risk of gingival and periodontal diseases. They also have difficulty in controlling oral muscles; a progressive decrease in number of tongue fungiform papillae, accompanied by lack of taste buds; and specific dysgeusia, but a normal sense of smell.

Submandibular and sublingual salivary gland function in familial dysautonomia

OBJECTIVE

Drooling in familial dysautonomia (FD) has been attributed to denervation supersensitivity. The aim of this study was to investigate submandibular and sublingual (SM/SL) gland function in FD.

STUDY DESIGN

SM/SL saliva was collected from 15 children with FD and from 31 healthy control subjects. The protein and electrolyte content and the salivary flow rate were determined in each subject.

RESULTS

Children with FD displayed significantly elevated outputs of chloride, potassium, calcium, phosphorous, magnesium, and total protein. Salivary flow rates were significantly increased. Phosphorous concentration was statistically low. These results imply SM/SL hyperfunction at the acinar and ductal levels. The concentration of lysozyme, the activity of amylase, and the output of both were similar in patients and control subjects.

CONCLUSION

SM/SL gland hyperactivity is a newly described abnormality in FD. At the acinar level, this hyperactivity is expressed with increased fluid, electrolyte, and protein output, and at the ductal level, with increased ion secretion and absorption rate. These changes may be the result of ongoing parasympathetic denervation characteristic in FD.

A cephalometric evaluation of craniofacial morphology in familial dysautonomia

OBJECTIVE

The purpose of this study was to delineate the craniofacial and dentoalveolar morphology of patients with familial dysautonomia (FD) in order to contribute to the understanding of the association between progressive sensory and autonomic neuropathy and the characteristic appearance of the dysautonomic face.

PATIENTS

The study group comprised 32 patients with FD (15 females and 17 males; mean age 10.8 years, SD 3.5 years, range 5.8-19.8 years).

DESIGN

Lateral cephalograms from each patient were traced twice. The means of the two measurements were compared with homologous cephalometric normal values of ethnic-specific and classical norms from the literature.

RESULTS

In some parameters, the craniofacial morphology of the FD group was significantly different from the classical norms. There was a pronounced retrognathism in the mandible and a steep mandibular plane angle. The skeletal features of FD patients more closely resembled those of their ethnic group, although they were more retrognathic, and the mandibular growth axis was more horizontal. The incisors of these patients were more retropositioned and retroclined than were those of their healthy counterparts.

CONCLUSIONS

The results suggest an insufficiency of the expected dentoalveolar compensatory mechanism that usually helps to bridge skeletal discrepancies. It is postulated that the neuropathy is probably the important factor in the lack of this compensatory mechanism.

Abnormal enamel and pulp dimensions in familial dysautonomia

In familial dysautonomia (FD), a hereditary autonomic and sensory neuropathy, somatic growth is impaired. This study was conducted to explore the possibility that tooth dimensions are altered as a consequence of neural crest dysfunction known to be present in FD. Enamel, dentin, pulp, and tooth size measurements of mandibular primary and permanent molars from FD patients were compared with those of healthy controls. It was found that although tooth size in the FD patients was smaller than normal, the enamel was thicker on the occlusal table, while the pulp chamber was smaller and disproportional to tooth size. Our results suggest distorted tooth dimensions rather than a generalized growth arrest as observed in other hereditary syndromes, such as Down's or Crouzon.

Oro-dental self-mutilation in familial dysautonomia

Orodental self-mutilation (ODSM) has not gained sufficient recognition in familial dysautonomia (FD). Among 38 patients with FD, ODSM was found in 14 (36.8%). ODSM may be due to peripheral neuropathy with insensibility to pain, which is characteristic of FD. Elimination of the sharp edges of teeth was found to be helpful.

Oro-dental management of patients with familial dysautonomia

Oro-dental abnormalities are quite frequent in familial dysautonomia. The practitioner should be familiar with this disorder, which represents a "human model" for chronic progressive oro-dental denervation. Self-injurious behavior is caused mainly by profound sensory loss. An appropriate preventive and therapeutic approach that was developed in our clinic and adapted for the special hazards of dentistry in youngsters with systemic autonomic dysfunction may improve the life quality of this particular population.