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Background: Familial dysautonomia (Riley-Day syndrome) is an autosomal recessive disorder primarily affecting individuals of Ashkenazi Jewish extraction. It affects the autonomic, central, and peripheral nervous systems. Spinal deformity (mainly scoliosis) is the most common orthopaedic problem in patients with familial dysautonomia. The objectives of our study were to document the prevalence of spinal deformity in a referral center for familial dysautonomia and to determine the effectiveness of bracing.Methods: We performed a retrospective radiographic and clinical study of 123 patients with familial dysautonomia who had survived to the age of twenty years or older.Results: One hundred and two (83 percent) of the 123 patients had spinal deformity: sixty-nine (56 percent) had scoliosis only, thirty-one (25 percent) had scoliosis as well as kyphosis, and two (2 percent) had kyphosis only. Scoliosis was diagnosed by the age of ten years in sixty-four (52 percent) of the patients. Of the sixty-five patients who were treated with bracing, fifty-eight (89 percent) had progression and twenty-four (37 percent) underwent spinal arthrodesis. No risk factors for the presence or progression of the curves could be found.Conclusions: The prevalence of spinal deformity in patients with familial dysautonomia who had lived for at least twenty years was found to be 83 percent. By the age of ten years, 52 percent of the patients had scoliosis and 21 percent had kyphosis with or without scoliosis. Bracing was found to be of limited effectiveness as a definitive treatment for spinal deformity. The curve progressed despite bracing in fifty-eight (89 percent) of sixty-five patients. [ABSTRACT FROM AUTHOR]

Objective: To identify electrocardiographic predictors of mortality in patients with familial dysautonomia (FD)., Methods: Ten-minute resting high-fidelity 12-lead electrocardiograms (ECGs) were obtained from 14 FD patients and 14 age/gender-matched healthy subjects. Multiple conventional and advanced ECG parameters were studied for their ability to predict mortality over a subsequent 4.5-year period, including representative parameters of heart rate variability (HRV), QT variability (QTV), T-wave complexity, signal averaged ECG, and 3-dimensional ECG., Results: Four of the 14 FD patients died during the follow-up period, three with concomitant pulmonary disorder. Of the ECG parameters studied, increased non-HRV-correlated QTV and decreased HRV were the most predictive of death. Compared to controls as a group, FD patients also had significantly increased ECG voltages, JTc intervals and waveform complexity, suggestive of structural heart disease., Conclusion: Increased QTV and decreased HRV are markers for increased risk of death in FD patients. When present, both markers may reflect concurrent pathological processes, especially hypoxia due to pulmonary disorders and sleep apnea.

In familial dysautonomia (FD), i.e. Riley-Day-syndrome, sympathetic cardiovascular function, as well as afferent temperature and pain mediating neurons, are significantly reduced. Thus, it was questioned if cold pressor test (CPT), which normally enhances sympathetic outflow and induces peripheral vasoconstriction by the activation of thermo- and nociceptive system activation, could be used to assess sympathetic function in FD. To evaluate whether CPT can be used to assess sympathetic activation in FD, we performed CPT in 15 FD patients and 18 controls. After a 35-min resting period, participants immersed their right hand and arm up to the elbow into 0-1 degrees C cold water while we monitored heart rate (HR), respiration, beat-to-beat radial artery blood pressure (BP), and laser Doppler skin blood flow (SBF) at the right index finger pulp. From these measurements, heart rate variability parameters were calculated: root mean square of successive differences (RMSSD), coefficient of variation (CV), low and high frequency (LF, HF) power spectra of the electrocardiogram (ECG). All participants perceived cold stimulation and indicated discomfort. In controls, SBF decreased and HR and BP increased rapidly upon CPT. After 60 s, SBF indicated secondary vasodilatation in six controls, BP rise attenuated and HR returned to baseline in all controls. In the patients, SBF remained unchanged, HR and BP increased significantly, but after 50-60 s of CPT and changes were lower than in controls (p<0.05). RMSSD and CV decreased and LF increased significantly only in the controls. We conclude that CPT activates sympathetic HR and BP modulation despite impaired pain and temperature perception in FD patients. BP increase in the presence of almost unchanged SBF might be due to HR increase and to nociceptive arousal and emotionally induced catecholamine release as seen in emotional crises of FD patients. CPT assesses sympathetic cardiovascular responses independently from baroreflex function, which is compromised in FD.

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: p<0.05). 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.

Familial dysautonomia (FD; also known as "Riley-Day syndrome"), an Ashkenazi Jewish disorder, is the best known and most frequent of a group of congenital sensory neuropathies and is characterized by widespread sensory and variable autonomic dysfunction. Previously, we had mapped the FD gene, DYS, to a 0.5-cM region on chromosome 9q31 and had shown that the ethnic bias is due to a founder effect, with >99.5% of disease alleles sharing a common ancestral haplotype. To investigate the molecular basis of FD, we sequenced the minimal candidate region and cloned and characterized its five genes. One of these, IKBKAP, harbors two mutations that can cause FD. The major haplotype mutation is located in the donor splice site of intron 20. This mutation can result in skipping of exon 20 in the mRNA of patients with FD, although they continue to express varying levels of wild-type message in a tissue-specific manner. RNA isolated from lymphoblasts of patients is primarily wild-type, whereas only the deleted message is seen in RNA isolated from brain. The mutation associated with the minor haplotype in four patients is a missense (R696P) mutation in exon 19, which is predicted to disrupt a potential phosphorylation site. Our findings indicate that almost all cases of FD are caused by an unusual splice defect that displays tissue-specific expression; and they also provide the basis for rapid carrier screening in the Ashkenazi Jewish population.

Familial dysautonomia (FD) is a rare autosomal recessive disease occurring in Ashkenazi Jews. It affects the autonomic, central, and peripheral nervous systems. The purpose of this study was to assess the prevalence and characteristics of orthopedic deformities, other than spinal deformities, in this population. A retrospective review of the medical records and radiographs of 182 patients was made. Three main groups of orthopaedic conditions were evaluated: (a) Fractures: 60% of the patients had one or more fractures; the average fracture rate was 1.4/patient. (b) Neuropathic joints: 11% of the cases had one or more neuropathic joints, the knee being the most common. (c) Other musculoskeletal deformities: 26% of the patients had one or more deformities. Lower extremity rotational problems and foot anomalies accounted for most of these deformities. Patients with FD have a higher prevalence of fractures and neuropathic joints than do their peers. The fracture pattern also is different, with a higher incidence of proximal femoral fractures.

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.

A novel human transcript CG-2 (C9ORF5), was isolated from the familial dysautonomia candidate region on 9q31 using a combination of cDNA selection and exon trapping. CG-2 was detected as a relatively abundant 8kb transcript in all adult and fetal tissues with the exception of adult thymus. Genomic analysis of CG-2 identified 18 exons that span more than 110kb. The gene encodes a 911-amino-acid protein with a predicted molecular weight of 101kDa and a hypothetical pI of 9.03. Sequence analysis of CG-2 indicates that it is likely to encode a transmembrane protein. Here, we assess CG-2 as a candidate for familial dysautonomia.

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 HindIII 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., (Copyright 1999 Academic Press.)

Familial 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 <0.5 cM between the markers 43B1GAGT and 157A3. Two markers in this interval, 164D1 and D9S1677, show no recombination with the disease. Haplotype analysis confirmed this candidate region and revealed a major haplotype shared by 435 of 441 FD chromosomes, indicating a striking founder effect. Three other haplotypes, found on the remaining 6 FD chromosomes, might represent independent mutations. The frequency of the major FD haplotype in the Ashkenazim (5 in 324 control chromosomes) was consistent with the estimated DYS carrier frequency of 1 in 32, and none of the four haplotypes associated with FD was observed on 492 non-FD chromosomes from obligatory carriers. It is now possible to provide accurate genetic testing both for families with FD and for carriers, on the basis of close flanking markers and the capacity to identify >98% of FD chromosomes by their haplotype.

Objective: Electrocardiographic repolarization intervals were evaluated to determine the extent of cardiac autonomic dysfunction in patients with familial dysautonomia (FD) and to determine if any of these intervals could serve as a possible predictor of clinical symptoms., Methods: Thirty-seven electrocardiograms of patients with FD were retrospectively evaluated. QT, JT, rate-corrected QT and JT intervals were calculated as well as QT and QTC dispersion. Results were compared to normative data and electrocardiograms of 20 age-matched control subjects., Observations: In the FD group, prolongation of QTC (>450 msec) was noted in 5/37 (13.5%) patients, as compared to 0/20 normal controls (p = NS), and prolongation of JTc (>340 msec) in 16/37 (43.3%) patients, as compared to 0/20 normal controls (p < 0.001). QT and QTC dispersion were abnormal in 3/37 (8.1%) and 5/37 (13.5%), respectively. In the 16 FD patients with prolonged JTc, six had a positive history of syncope, whereas none of the 21 with normal JTc had syncope or symptoms suggesting arrhythmia (p < 0.003). The positive predictive value of having syncope or symptoms suggestive of arrhythmia with an abnormal JTc is 37.5% (95% CI [15%, 65%]). The negative predictive value is 100% (95% CI [87%, 100%])., Conclusion: In the FD population, the electrocardiographic measure of repolarization that was most frequently abnormal was the JTc interval . Prolongation of the JTc interval was significantly more frequent than prolongation of the QTC interval (p < 0.001) QT and QTC dispersions were less significantly affected in the FD population, indicating uniform ventricular recovery time. These results suggest that a prolonged JTc interval may be a more sensitive indicator of abnormal ventricular repolarization and cardiac autonomic dysfunction. Due to the known sympathetic denervation inherent in patients with FD, they are at risk for unopposed parasympathetic predominance. FD patients, therefore, are more likely to have brady arrhythmias and asystole rather than polymorphic ventricular tachycardia. The increased incidence of syncope in patients with prolonged JTc suggests that this measure may serve as a helpful marker to predict which FD patients are at increased risk of serious clinical sequelae including bradyarrhythmias with asystole or sudden death.