Search

Objective assessment of autonomic dysfunction in familial dysautonomia (FD) is largely based on the analysis of cardiovascular responses to challenge maneuvers such as orthostatic stress. Infrared pupillometry (IPM) provides an additional reliable method for cranial autonomic evaluation and has the advantage of requiring minimal cooperation.This study was performed to determine whether IPM contributes to the assessment of autonomic function in FD patients. In 14 FD patients and 14 healthy controls, we studied absolute and relative light reflex amplitude, pupillary constriction velocity (v(constr)), pupillary diameter, early and late pupillary re-dilatation velocity (v(dil 1), v(dil 2)) after dark adaptation. Prior to IPM, all patients had an ophthamological examination to evaluate refraction and corneal integrity. In comparison to controls, patients had a significant reduction of the parameters reflecting parasympathetic pupillary function (absolute light reflex amplitude 1.34 +/- 0.21 vs. l.86 +/- 0.14 mm, relative light reflex amplitude 22.74 +/- 7.11% vs. 30.76 +/- 3.57%, v(constr) 3.75 +/- 1.09 vs. 5.80 +/- 0.59 mm/s) and of the parameters reflecting sympathetic pupillary function (diameter 5.69 +/- 0.66 vs. 6.35 +/- 0.60 mm, v(dil 1) 1.29 +/- 0.23 vs. 1.95 +/- 0.23 mm/s, v(dil 2) 0.64 +/- 0.13 vs. 0.72 +/- 0.l2 mm/s; Mann-Whitney U-test: p0.05). The non-invasive technique of IPM demonstrates dysfunction not only of the cranial parasympathetic, but also of the cranial sympathetic nervous system and, thus, further characterizes autonomic dysfunction in FD.

The case of a transient third degree atrioventricular block in a 4-year-old patient with familial dysautonomia is reported. A review of the literature follows with analysis of the significance of arrhythmias in the natural history of the patient with familial dysautonomia.

Familial dysautonomia (FD) is an inherited disorder that is known to affect both sensory and autonomic functions as a result of incomplete neuronal development and progressive loss but the degree to which patients are affected differs greatly. To determine if quantitative vibration and thermal testing refined the assessment of severity, 23 familial dysautonomia patients were evaluated by clinical examination, measurements of median, peroneal and sural nerve conduction velocities (NCV), and assessment of vibration thresholds at two body sites and of warm and cold perception thresholds at 6 body sites using the method of limits. Data from 80 age-matched normal individuals provided control data for vibration and temperature thresholds. All familial dysautonomia patients had abnormal thermal thresholds. Vibration perception was abnormal in 20 patients. NCVs were slowed in 8 of 16 patients who agreed to be tested. Abnormalities in thermal thresholds are consistent with the reduction of small nerve fibers in familial dysautonomia Abnormal vibration thresholds might be due to disturbed conduction of vibratory impulse trains and reflect the degree to which the disorder is progressive. Vibration and thermal sensation testing were better accepted and provided more information than NCV regarding severity of disease.

Two novel human actin-like genes, ACTL7A and ACTL7B, were identified by cDNA selection and direct genomic sequencing from the familial dysautonomia candidate region on 9q31. ACTL7A encodes a 435-amino-acid protein (predicted molecular mass 48.6 kDa) and ACTL7B encodes a 415-amino-acid protein (predicted molecular mass 45.2 kDa) that show greater than 65% amino acid identity to each other. Genomic analysis revealed ACTL7A and ACTL7B to be intronless genes contained on a common 8-kb Hin dIII fragment in a “head-to-head” orientation. The murine homologues were cloned and mapped by linkage analysis to mouse chromosome 4 in a region of gene order conserved with human chromosome 9q31. No recombinants were observed between the two genes, indicating a close physical proximity in mouse. ACTL7A is expressed in a wide variety of adult tissues, while the ACTL7B message was detected only in the testis and, to a lesser extent, in the prostate. No coding sequence mutations, genomic rearrangements, or differences in expression were detected for either gene in familial dysautonomia patients.

Cardiovascular abnormalities are prominent in the genetic disorder, familial dysautonomia (FD). To determine if autonomic dysfunction involves cardiac, as well as peripheral vascular integrity, noninvasive tests were performed in 10 FD patients and 8 healthy control subjects while supine and at 90 degrees tilt. Simultaneous blood pressure (BP) and heart rate (HR) and QTc were obtained, while performing signal-averaged electrocardiography (SAECG) and heart rate variability (HRV). FD subjects were tested on 2 separate days, before and 1 h after oral fludrocortisone or midodrine; controls were tested once without medication. With tilt, all FD subjects decreased mean BPor = 24 mm Hg by 5 min. On SAECG, 70% of supine FD subjects had a prolonged tQRS; only 2 FD subjects shortened tQRS with tilt. The QTc interval was prolonged (440 ms) in 2 supine FD subjects; with tilt, the QTc prolonged in a third. Frequency domain analysis of HRV revealed that mid (MF) and high frequency band areas were significantly decreased when supine, but not when upright. On time domain analysis, the pNN50 was significantly decreased in FD subjects (8.9 +/- 1.7 vs. 17.7 +/- 3.6%, p0.01). Fludrocortisone lowered supine BP and HR and increased supine MF area. Midodrine raised supine and erect BP, lowered erect HR, and shortened erect QTc. Although all FD subjects have abnormal orthostatic BP and HR responses, cardiac tone, as assessed by electrocardiographic and HRV responses, varies. Prolongation of the tQRS appears to be a sensitive but not specific indicator of autonomic dysfunction. QTc prolongation may indicate more extensive sympathetic dysfunction. HRV data suggest some FD patients have abnormalities in parasympathetic, as well as sympathetic, cardiac tone.

Publisher Summary Clinical features of familial dysautonomia (FD) encompass sensory and autonomic disturbances. Consistent peripheral neuropathologic findings suggest arrested development of the unmyelinated neuronal population, as well as progressive neurological deterioration. Plasma levels of catechols, as well as their metabolites have been investigated to define better the neurochemical phenotype and elucidate possible pathophysiological mechanisms. It has been demonstrated that FD patients have disproportionately high plasma levels of dihydroxyphenylalanine (DOPA) and low plasma levels of dihydroxyphenylglycol (DHPG), with strikingly elevated plasma DOPA/DHPG ratios. This pattern of plasma catechols is distinctly different than that found in other disorders associated with neurogenic orthostatic hypotension. Patients with acquired dysautonomia because of multiple system atrophy have normal supine norepinephrine (NE) and normal DOPA/DHPG ratios. Patients with dopamine β -hydroxylase (DBH) deficiency had barely detectable levels of NE when supine, no detectable DHPG, markedly elevated DOPA and dihydroxyphenylacetic acid (DOPAC) levels, and extremely high DOPA/DHPG and DOPAC/DHPG ratios. The normal supine NE levels but low DHPG levels in FD are intriguing. The normal supine plasma NE levels in FD patients are also consistent with decreased neuronal re-uptake of released NE because of sparse sympathetic innervation and perhaps ongoing constitutive neurosecretion. These studies may guide genetic investigators toward factors that would influence neurodevelopment, as well as differentiation of catecholaminergic systems.

This report extends previous investigations of endogenous catecholamine levels in patients with orthostatic hypotension due to familial dysautonomia (FD), to define better the neurochemical phenotype and elucidate possible pathophysiological mechanisms. Ten FD patients (age 26.1 +/- 2.6 (SEM) years) and eight control subjects (age 29.5 +/- 3.7 years) were studied. Heart rate, blood pressure and venous blood samples were obtained while supine and after 5 min in the upright position. Plasma levels of dihydroxyphenylalanine (DOPA), noradrenaline (NA), adrenaline (A), dopamine (DA), dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC) were measured. When supine, the FD group had greater NA and DOPA levels, and lower DHPG levels. Plasma NA did not increase with erect posture in FD patients. Individual FD mean blood pressures were correlated positively with plasma NA levels when supine and with plasma DA and DOPAC when upright. In FD, DOPA:DHPG ratios were above the range found in normal subjects or that reported in patients with acquired forms of dysautonomia regardless of posture, whereas DOPAC:DHPG ratios remained normal. Thus FD patients have a characteristic neurochemical pattern which probably reflects either decreased vesicular storage of catecholamines or limited oxidative deamination despite normal or increased tyrosine hydroxylation.

We describe two Hispanic adolescents with Allgrove syndrome (alacrima, achalasia, and sensorimotor polyneuropathy) in whom we documented cholinergic dysfunction by cardiovascular autonomic tests. Both patients had orthostatic hypotension and decreased heart rate variability.

The neurotrophic tyrosine kinase receptor type 2 (NTRK2) gene is a member of the trk family of tyrosine protein kinases, which encode receptors for the nerve growth factor-related proteins known as neurotrophins. The neurotrophins and their receptors have long been considered candidate genes for familial dysautonomia (FD), a hereditary sensory neuropathy resulting from the congenital loss of both sensory and autonomic neurons. The DYS gene has recently been mapped to human chromosome 9q31–q33, and therefore we set out to determine the chromosomal localization of the candidate gene NTRK2. A mouse trkB probe was hybridized to both somatic cell hybrids containing human chromosome 9 and a human chromosome 9 flow-sorted cosmid library. The human homologue of trkB, NTRK2, was assigned to chromosome 9. To localize the NTRK2 gene further, a dinucleotide repeat polymorphism was identified within a cosmid that contains NTRK2 exon sequences. This marker was genotyped in the CEPH reference pedigrees and places the NTRK2 gene near D9S1 on the proximal long arm of human chromosome 9. The NTRK2 gene is located approximately 22 cm proximal to DYS and shows several recombinants in disease families. Therefore, the NTRK2 gene can now be excluded as a candidate gene for familial dysautonomia.

Circulating atrial natriuretic peptide (ANP) was assayed before and after postural change and exercise in 54 patients with familial dysautonomia (FD) and 20 controls. ANP levels were compared with blood pressure, heart rate, plasma catecholamines and parameters of renal function. Compared with controls supine FD subjects had elevated blood pressures, heart rates and ANP levels (39 ± 4 pg/ml vs. 23 ± 3 pg/ml,p < 0.01). With the erect posture and exercise in FD subjects, blood pressure fell below control values, with ANP lowered. In FD subjects, blood pressure was correlated with ANP levels when supine and when erect and with heart rate post exercise. In controls, ANP levels did not correlate with other parameters. In FD patients on metoclopramide, supine and erect blood pressure and ANP levels were higher. FD subjects treated with fludrocortisone, had elevated supine and erect noradrenaline (p < 0.05 andp = 0.06); and those on diazepam had lower erect and post exercise noradrenaline (p < 0.05), but ANP levels were similar. In conclusion, sympathetic denervation may increase FD patients' responsiveness to other regulators of cardiovascular integrity, such as ANP. In addition, circulating ANP and catecholamines in FD subjects appear to be influenced by commonly used medications, such as metoclopramide.

Familial dysautonomia (DYS), the Riley-Day syndrome, is an autosomal recessive disorder characterized by developmental loss of neurons from the sensory and autonomic nervous system. It is limited to the Ashkenazi Jewish population, where the carrier frequency is 1 in 30. We have mapped the DYS gene to chromosome 9q31-q33 by linkage with ten DNA markers in 26 families. The maximum lod score of 21.1 with no recombinants was achieved with D9S58. This marker also showed strong linkage disequilibrium with DYS, with one allele present on 73% of affected chromosomes compared to 5.4% of controls (chi 2 = 3142, 15 d.f. p < 0.0001). D9S53 and D9S105 represent the closest flanking markers for the disease gene. This localization will permit prenatal diagnosis of DYS in affected families and aid the isolation of the disease gene.

Fundoplication with gastrostomy has become a frequent treatment for patients with familial dysautonomia, so we evaluated the use of both procedures in 65 patients. Although patients differed widely in presenting signs and age, from 5 weeks to 40 years, gastroesophageal reflux was documented in 95% of patients by cineradiography or pH monitoring. Panendoscopy was a useful adjunct. Preoperative symptoms of gastroesophageal reflux included vomiting, respiratory infections, and exaggerated autonomic dysfunction. Severe oropharyngeal incoordination frequently coexisted and resulted in misdirected swallows with aspiration, dependence on gavage feedings, or poor weight gain and dehydration. Follow-up after surgical correction ranged from 3 months to 11 years; 55 patients (85%) were available for a 1-year postoperative assessment. We had no instances of surgical death. The long-term mortality rate was 14%, primarily related to severe preexisting respiratory disease. Beyond the first postoperative year, 30 patients had pneumonia attributed to continued aspiration, exacerbation of preexisting lung disease, or recurrence of gastroesophageal reflux. Of 11 patients who vomited postoperatively, six had recurrence of reflux. Recurrence of gastroesophageal reflux was documented in eight patients (12%), and we revised the fundoplication in three patients. The number of patients with cyclic crises was reduced from 18 to 7; retching replaced overt vomiting in all but two of these seven patients, neither of whom had recurrence of reflux. Because oropharyngeal incoordination was prominent, concomitant use of gastrostomy and an antireflux procedure was especially effective in the treatment of younger patients with familial dysautonomia, before the development of severe respiratory disease. Despite the development of severe morning nausea in 15 patients, the combination procedure resulted in significantly improved nutritional status, decreased vomiting, and decreased respiratory problems. Appropriate use of gastrostomy feedings also contributed to success of the operation. The generally good outcome of fundoplication with gastrostomy confirms the benefit of this procedure in familial dysautonomia.

In 225 adults aged 18 to 80 years, normative warm and cold perception thresholds were assessed at the volar distal forearm, thenar eminence, lower medial calf, and lateral dorsal foot using the method of limits and a Thermotest (Somedic, Stockholm, Sweden). A 1.5-cm x 2.5-cm thermode, a 1 degrees C/s stimulus change rate, and a 32 degrees C baseline temperature were applied. Thresholds of five consecutive stimuli were averaged. At the thenar eminence a 3 degrees C/s stimulation was applied in addition to the 1 degree C/s stimulation. Effects of spatial summation were studied at the calf and forearm by additional testing with a 2.5-cm x 5.0-cm thermode. To evaluate the influence of skin temperature, thresholds were correlated with the pretest skin temperature at the tested sites. Reproducibility of stimulus perception was determined by comparing the lowest to the highest response to five consecutive stimuli. Results showed sufficient accuracy of thermal perception thresholds. Thresholds were higher with the 3 degrees C/s stimulation than with the 1 degree C/s stimulation. Thresholds were lower with the large than with the small probe. Skin temperature had only minimal influence on thresholds. The use of a 32 degrees C baseline temperature and a 1 degree C/s stimulus change rate is recommended. The large probe should be used at body sites where the entire thermode surface adjusts planely to the skin. Warming up the tested skin area is not necessary before thermotesting.

Objective: To evaluate whether sympathetic skin response (SSR) differs in patients with hereditary sensory autonomic neuropathy (HSAN) types III and IV.Background: HSAN types III and IV are rare autosomal recessive disorders that cause many similar autonomic, sensory, and motor dysfunctions, but different sweating characteristics. HSAN III patients have preserved and at times, excessive sweating, whereas anhidrosis is characteristic of HSAN IV. SSR reflects the integrity of sympathetic sudomotor fibers and the activation of sweat glands through the change in skin resistance in response to an arousal stimulus. Therefore, SSR is a test method that might facilitate differential diagnosis of HSAN III and IV.Methods: In 17 HSAN III patients (eight women, nine men; mean age, 20.65 ± 5.45 years) and seven HSAN IV patients (five girls, two boys; mean age, 10.0 ± 5.45 years) SSR was recorded from the palms and soles after repeated electrical, acoustic, and inspiratory gasp stimulations. In addition, all subjects underwent a neurologic examination; studies of median, peroneal motor, and sural nerve conduction velocities; and determination of vibratory and thermal perception thresholds.Results: Although clinical differences were appreciated between the two types of HSANs, both HSANs had evidence of small-fiber involvement. Both HSANs had abnormal temperature and pain perception. In contrast, SSR was preserved in all HSAN III and absent in all HSAN IV patients.Conclusion: SSR provides another parameter to improve differentiation of HSAN III from HSAN IV, and also gives us additional information regarding sympathetic sudomotor fiber function in these developmental diseases.

Three patients who appear to have a previously undescribed congenital neuropathy are described. None is of Ashkenazi Jewish extraction, but each seems to fulfill the clinical diagnostic criteria for familial dysautonomia. All lack overflow tears, fungiform papillae, and deep-tendon reflexes; intradermal administration of histamine did not produce an axon flare. Intraocular instillation of dilute mecholyl produced miosis in the one patient tested. In contrast to patients with familial dysautonomia, the three patients had universal loss of pain sensation, profound hypotonia, and unusual facies. Pathologic examination of the sural nerve in one patient was not consistent with the usual findings in familial dysautonomia. These patients are believed to have a previously undescribed congenital neuropathy.

We examined 12 patients with familial dysautonomia who had clear corneas to determine if there was any optic nerve involvement. The patients ranged in age from 6 to 34 years. Visual acuity ranged from 20/20 to 20/100. Nineteen eyes of 12 patients (79%) had abnormal (mean +/- 3 S.D.) pattern reversal visual-evoked potentials as compared to 50 control eyes (P100 = 98.8 msec; S.D., +/- 4.5 msec). P100 latency appeared to worsen with age. Exodeviation was present in seven patients (58%) and correlated with visual acuity and P100 latency. Ophthalmoscopic examination showed some degree of optic nerve pallor in all eyes.

The developmental loss of neurons in sympathetic, sensory, and some parasympathetic ganglia in familial dysautonomia suggests an inherited defect in the action of beta-nerve growth factor (beta-NGF). The role of this growth factor in dysautonomia has been difficult to resolve as there is no known source of authentic human beta-NGF. The availability of a cloned DNA probe for the human beta-NGF gene has allowed identification of some copies of the gene (alleles) in six affected families. Alleles differ in the length of restriction endonuclease fragments that hybridize to DNA probes for the gene. In two families, affected children did not inherit the same two alleles at the beta-NGF locus. Since this disease is transmitted in an autosomal recessive manner, affected children must share the same alleles at the locus causing the disease. This analysis excludes the beta-NGF gene region as the cause of this neurologic disease but does not eliminate other genes involved in beta-NGF action, such as those coding for processing enzymes, receptors, or other subunits of the NGF complex.

In familial dysautonomia there are malfunctions of motor, sensory and autonomic systems. The sural nerve has reduced transverse fascicular area, diminished numbers of myelinated axons (particularly those of small diameter) and very few non-myelinated axons. Catecholamine containing endings are not found in accompanying arteries. These changes are compatible with reduced neuronal populations described in sympathetic and sensory ganglia. The observed pathology accounts for many of the clinical features of the disease and suggests an abnormality in intrauterine development.

This paper describes physical therapy programs to assist physical therapists in the rehabilitation of patients with familial dysautonomia. There have been no reports in the literature about a physical therapy program for patients with this disease. A retrospective analysis of the clinical manifestations in 80 patients in a dysautonomia clinic was performed. Scoliosis and kyphosis were found in 92 percent of the patients, 93 percent had ataxia, 74 percent had feeding difficulties, 69 percent had frequent pneumonias, and 63 percent exhibited delayed developmental milestones. Cardiovascular, gastrointestinal, pulmonary, musculoskeletal, and neurological symptoms and treatments are discussed.

The effects of Urecholine have been investigated in six children with familial dysautonomia. There was an increase in eye moisture, a reduction in gastric distension and vomiting, improvement in esophageal motility, and better bladder control. Urecholine may prove an effective therapeutic agent for selected patients with familial dysautonomia.

SummaryFamilial dysautonomia (FD) is an autosomal recessive disorder characterized by developmental arrest in the sensory and autonomic nervous systems and by Ashkenazi Jewish ancestry. We previously had mapped the defective gene (DYS) to an 11-cM segment of chromosome 9q31-33, flanked by D9S53 and D9S105. By using 11 new polymorphic loci, we now have narrowed the location of DYS to 98% of FD chromosomes by their haplotype.

FAMILIAL DYSAUTONOMIA can no longer be considered solely a disease of childhood; increasing numbers of patients are reaching adulthood. At the Dysautonomia Center at New York University Medical Center, 59 patients are 20 years or older and account for 33% of the living patient population; the oldest patient at time of writing is 38 years of age. Previously the only analysis of survival probability was a retrospective study compiled by Brunt and MeKusick ~ in 1970. With the establishment of a center for evaluation and treatment in 1969, a large number of patients could be followed and receive more consistent treatment. We have reanalyzed mortality figures to determine current survival and the general prognosis for patients with familial dysautonomia.

This report describes the first two known instances of viable pregnancies in two patients with familial dysautonomia (Riley-Day syndrome). The offspring were apparently normal. Several conditions, specifically related to autonomic and sensory dysfunction in pregnancy, are discussed.

Arterial blood pressure (BP), heart rate (HR) and plasma concentration of norepinephrine (NE), epinephrine (EPI), dopamine (DA) and dopamine-s-hydroxylase (DBH) were measured in ten normal and ten familial dysautonomic subjects just after 15 minutes recumbent, 1 minute, and 10 minutes standing. The mean BP in the supine position for the familial dysautonomic patient was higher than that of the normal (p

The availability of cloned human DNA sequences combined with classic methods of genetic linkage analysis allows us to establish whether a mutation in a given gene produces an inherited disease state. In this chapter, we will describe how cloned DNA probes corresponding to the human gene for β-nerve growth factor (βNGF) can be used to determine whether an alteration in the structure or expression of this gene is the primary defect in the inherited neurological disease familial dysautonomia. Our preliminary findings are also presented.

Gastric and esophageal dysfunction are components of familial dysautonomia. The limited success of various medical management programs, has led to two types of surgical intervention. Experience with nine patients who had gastrostomy alone and 12 patients who had gastroesophageal fundoplication is reviewed. Both surgical procedures decreased frequency of vomiting and pneumonias and had positive effects on weight gain. Although "dysautonomic crises" are not eliminated, sufficient modification in character occurs so that associated risks are lessened. It is suggested that if medical management cannot control recurrent pneumonia, postprandial vomiting, esophageal bleeding, and/or inadequate weight gain, then the patient should be evaluated for fundoplication and/or gastrostomy.

Renal disease in familial dysautonomia. A study of renal disease in familial dysautonomia identified excess glomerulosclerosis in 10 of 13 autopsied and biopsied patients. Sympathetic nerve terminals could not be found on renal vessels in biopsied tissue; they were invariably demonstrable in controls. Altered renovascular responsivity to systemic hypotension in familial dysautonomia may lead to ischemia and subsequent sclerosis of glomeruli. Review of 79 living outpatients showed that clinically overt renal disease was rare in familial dysautonomia. Nevertheless, frequent observations of elevations of serum creatinine concentrations (32% of patients) and blood urea concentrations (76% of patients) indicated a high prevalence of abnormality. An association was found between hypotension and renal dysfunction. Atteinte renale dans la dysautonomie familiale. Une etude de l'atteinte renale dans la dysautonomie familiale a identifie une glomerulosclerose excessive chez 10 malades parmi les 13 autopsies ou biopsies. Les terminaisons sympathiques n'ont pas pu etre mises en evidence dans les vaisseaux renaux des fragments biopsiques. Elles ont ete toujours observes dans les fragments controles. Une modification de la reponse renovasculaire a l'hypotension systemique au cours de la dysautonomie familiale peut conduire a l'ischemie puis a la sclerose glomerulaire. L'etude de 79 malades externes vivants a montre que l'atteinte renale cliniquement evidente est rare au cours de la dysautonomie familiale. Cependant, la constatation frequente de creatininemies elevees (32% des malades) et de concentrations plasmatiques d'uree elevees (76% des malades) indique une frequence elevee d'anomalies. Une association a ete constatee entre l'hypotension et la modification du fonctionnement renal.

We performed infrared pupillography on 10 patients with familial dysautonomia. Pupillary constriction to light and accommodation was normal. There was no evidence for light-near dissociation, and tonic responses were not observed. Dilatation in darkness was normal. Ocular application of dilute pilocarpine produced miosis in all patients. Supersensitivity of the pupil to muscarinic agents in familial dysautonomia is unlikely to be explained by parasympathetic denervation. Possible explanations for this phenomenon include diminished lacrimation and corneal ulcerations.

Intrauterine development and postnatal maintenance of dorsal root ganglion neurons are abnormal in familial dysautonomia, an autosomal recessive disorder associated with autonomic, motor and sensory deficits. Normally, dorsal root ganglion weight increases with age. This does not occur in the cervical plexus ganglia of dysautonomic patients. Neurons in dorsal root ganglia are found to be markedly diminished in the youngest patients and slow degeneration causes further depletion with age. Quantitative studies on C8 dorsal root ganglia show the normal neuron content to be between 42,500 and 53,600. In 3 patients with familial dysautonomia the range was 4,090–8,590 with the smallest number being in the oldest patient. Lateral root entry zones and Lissauer's tracts are severely depleted of axons. In older patients loss of dorsal column myelinated axons becomes evident and is first seen in lumbar fasciculus gracilis, cervical fasciculus cuneatus and interfascicular fasciculus. Temperature sensation is markedly impaired from infancy in familial dysautonomia. Loss of pain sensation is prominent and worsens with age. Vibration sense diminishes in adolescence and coordination of limb movements becomes poor in older patients. Neuron depletion in dorsal root ganglia and the progressive pattern of cord changes correlate well with these clinical observations.

Publisher Summary This chapter discusses familial dysautonomia, which is the most extensively described of the disorders known as congenital sensory neuropathies. Although the major known anatomic abnormality in familial dysautonomia is caused by anatomic depletion of sensory and autonomic neurons, it is the clinical manifestations that are the concern of the treating physician. Signs of the disorder are present from birth, and neurologic function exhibits a slow and variable deterioration with age such that symptoms and problems alter with time. Gastrointestinal problems are among the earliest symptoms. There is a high incidence of juvenile scoliosis in familial dysautonomia. Lack of overflow or emotional tearing is one of the cardinal signs of the disorder. Pathologically familial dysautonomia is a congenital developmental disorder onto which a prolonged degenerative process is superimposed. A common causative deficiency, which affects both production and maintenance of neurons in this autosomal recessive condition, is likely to be found.

NERVE-GROWTH factors have been isolated from a variety of substances such as sarcoma, snake venoms and the spinal-axial region of the chick embryo. The best source has been the submandibular saliva...

respiratory distress syndrome. It is unclear why SOD appeared to be effective in modifying pulmonary disease in human infants at relatively low doses, yet failed to modify sequelae in the present animal models, despite substantially higher doses of the enzyme. The lungs of both the preterm infant (