Clinical relevance and neurophysiological correlates of spasticity in cerebrotendinous xanthomatosis

Pathophysiology and Treatment of Lipid Abnormalities in Cerebrotendinous Xanthomatosis: An Integrative Review

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disorder caused by pathogenic variants in CYP27A1, leading to a deficiency in sterol 27-hydroxylase. This defect results in the accumulation of cholestanol and bile alcohols in various tissues, including the brain, tendons and peripheral nerves. We conducted this review to evaluate lipid profile abnormalities in patients with CTX. A search was conducted in PubMed, Embase and the Virtual Health Library in January 2023 to evaluate studies reporting the lipid profiles of CTX patients, including the levels of cholestanol, cholesterol and other lipids. Elevated levels of cholestanol were consistently observed. Most patients presented normal or low serum cholesterol levels. A decrease in chenodeoxycholic acid (CDCA) leads to increased synthesis of cholesterol metabolites, such as bile alcohols 23S-pentol and 25-tetrol 3-glucuronide, which may serve as surrogate follow-up markers in patients with CTX. Lipid abnormalities in CTX have clinical implications. Cholestanol deposition in tissues contributes to clinical manifestations, including neurological symptoms and tendon xanthomas. Dyslipidemia and abnormal cholesterol metabolism may also contribute to the increased risk of atherosclerosis and cardiovascular complications observed in some CTX patients.

Motor Evoked Potentials in Newly Diagnosed and Treated Patients With Wilson Disease

PURPOSE

To investigate whether patients with Wilson disease have abnormal motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation.

METHODS

In a prospective, observational, single-center study, transcranial magnetic stimulation was used to examine MEPs recorded from the abductor digiti minimi in 24 newly diagnosed treatment-naive patients and 21 treated patients with Wilson disease.

RESULTS

Motor evoked potentials were recorded in 22 (91.7%) newly diagnosed treatment-naive patients and in 20 (95.2%) treated patients. Abnormal MEP parameters were found in a similar proportion of newly diagnosed and treated patients: MEP latency (38% vs. 29%), MEP amplitude (21% vs. 24%), central motor conduction time (29% vs. 29%), and resting motor threshold (68% vs. 52%). Abnormal MEP amplitude (P = 0.044) and resting motor threshold (P = 0.011) were more frequent in treated patients with brain MRI abnormalities but not in newly diagnosed patients. We did not observe significant improvement in MEPs parameters after 1 year of treatment introduction in eight examined patients. However, in one patient where MEPs were initially nondetectable, they were present 1 year after treatment introduction with zinc sulfate, although MEPs were not in the normal range.

CONCLUSIONS

Motor evoked potential parameters did not differ between newly diagnosed and treated patients. There was no significant improvement in MEP parameters one year after treatment introduction. Further studies conducted on large cohorts are necessary to determine the usefulness of MEPs in detecting pyramidal tract damage and improvement after anticopper treatment introduction in Wilson disease.

Balance impairment in cerebrotendinous xanthomatosis: Ankle strategy deficit. A case study

BACKGROUND

Cerebrotendinous xanthomatosis is a rare autosomal-recessive lipid storage disorder causing an elevation in cholestanol and cholesterol levels and their deposition in the central nervous system and tendons with consequent posture and gait disturbances.

METHODS

This report shows the case of a 36-year-old male affected by Cerebrotendinous xanthomatosis with static and dynamic instability. We aimed to provide an instrumented quantification of quiet upright standing using a piezoelectric force platform measuring the variations of center of pressure with the foot position 10 cm and 20 cm apart or extra-rotated with an opening angle of 30°, with eyes open or closed. The area of center of pressure and the length of its trajectory in the anterior-posterior and medial-lateral directions were computed. The temporal variability of center of pressure was evaluated by means of the Root Mean Square.

FINDINGS

In comparison with a control group, the area, the trajectory length of center of pressure in anterior-posterior and medial-lateral directions and the temporal variability increased in all static conditions. Intra-patient comparison showed that foot position 10 cm apart was the position that most influenced stability causing a marked worsening of area and trajectory length of center of pressure in both anterior-posterior and medial-lateral directions, particularly for the eyes closed condition.

INTERPRETATION

We found a large static instability due to internal neural and biomechanical constraints causing an insufficiency of ankle strategy. A physical therapy program based on instrumented proprioceptive exercises is to be implemented to teach the use of a hip strategy.

A comprehensive review of transcranial magnetic stimulation in secondary dementia

Although primary degenerative diseases are the main cause of dementia, a non-negligible proportion of patients is affected by a secondary and potentially treatable cognitive disorder. Therefore, diagnostic tools able to early identify and monitor them and to predict the response to treatment are needed. Transcranial magnetic stimulation (TMS) is a non-invasive neurophysiological technique capable of evaluating in vivo and in “real time” the motor areas, the cortico-spinal tract, and the neurotransmission pathways in several neurological and neuropsychiatric disorders, including cognitive impairment and dementia. While consistent evidence has been accumulated for Alzheimer’s disease, other degenerative cognitive disorders, and vascular dementia, to date a comprehensive review of TMS studies available in other secondary dementias is lacking. These conditions include, among others, normal-pressure hydrocephalus, multiple sclerosis, celiac disease and other immunologically mediated diseases, as well as a number of inflammatory, infective, metabolic, toxic, nutritional, endocrine, sleep-related, and rare genetic disorders. Overall, we observed that, while in degenerative dementia neurophysiological alterations might mirror specific, and possibly primary, neuropathological changes (and hence be used as early biomarkers), this pathogenic link appears to be weaker for most secondary forms of dementia, in which neurotransmitter dysfunction is more likely related to a systemic or diffuse neural damage. In these cases, therefore, an effort toward the understanding of pathological mechanisms of cognitive impairment should be made, also by investigating the relationship between functional alterations of brain circuits and the specific mechanisms of neuronal damage triggered by the causative disease. Neurophysiologically, although no distinctive TMS pattern can be identified that might be used to predict the occurrence or progression of cognitive decline in a specific condition, some TMS-associated measures of cortical function and plasticity (such as the short-latency afferent inhibition, the short-interval intracortical inhibition, and the cortical silent period) might add useful information in most of secondary dementia, especially in combination with suggestive clinical features and other diagnostic tests. The possibility to detect dysfunctional cortical circuits, to monitor the disease course, to probe the response to treatment, and to design novel neuromodulatory interventions in secondary dementia still represents a gap in the literature that needs to be explored.

Cerebrotendinous Xanthomatosis: Molecular Pathogenesis, Clinical Spectrum, Diagnosis, and Disease-Modifying Treatments

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder caused by mutations in the CYP27A1 gene, which encodes the mitochondrial enzyme sterol 27-hydroxylase. Decreased sterol 27-hydroxylase activity results in impaired bile acid synthesis, leading to reduced production of bile acids, especially chenodeoxycholic acid (CDCA), as well as elevated serum cholestanol and urine bile alcohols. The accumulation of cholestanol and cholesterol mainly in the brain, lenses, and tendons results in the characteristic clinical manifestations of CTX. Clinical presentation is characterized by systemic symptoms including neonatal jaundice or cholestasis, refractory diarrhea, juvenile cataracts, tendon xanthomas, osteoporosis, coronary heart disease, and a broad range of neuropsychiatric manifestations. The combinations of symptoms vary from patient to patient and the presenting symptoms, especially in the early disease phase, may be nonspecific, which leads to a substantial diagnostic delay or underdiagnosis. Replacement of CDCA has been approved as a first-line treatment for CTX, and can lead to biochemical and clinical improvements. However, the effect of CDCA treatment is limited once significant neuropsychiatric manifestations are established. The age at diagnosis and initiation of CDCA treatment correlate with the prognosis of patients with CTX. Therefore, early diagnosis and subsequent treatment initiation are essential.

Lipid metabolic pathways converge in motor neuron degenerative diseases

Motor neuron diseases (MNDs) encompass an extensive and heterogeneous group of upper and/or lower motor neuron degenerative disorders, in which the particular clinical outcomes stem from the specific neuronal component involved in each condition. While mutations in a large number of molecules associated with lipid metabolism are known to be implicated in MNDs, there remains a lack of clarity regarding the key functional pathways involved, and their inter-relationships. This review highlights evidence that defines defects within two specific lipid (cholesterol/oxysterol and phosphatidylethanolamine) biosynthetic cascades as being centrally involved in MND, particularly hereditary spastic paraplegia. We also identify how other MND-associated molecules may impact these cascades, in particular through impaired organellar interfacing, to propose ‘subcellular lipidome imbalance’ as a likely common pathomolecular theme in MND. Further exploration of this mechanism has the potential to identify new therapeutic targets and management strategies for modulation of disease progression in hereditary spastic paraplegias and other MNDs.

A Neuropsychological Profile for Cerebrotendinous Xanthomatosis: A Single-Case Study

OBJECTIVE

Cerebrotendinous xanthomatosis (CTX) belongs to a heterogeneous group of neurological disorders known as autosomal recessive cerebellar ataxias. Low awareness of CTX can result in misdiagnoses in the differential diagnostic process and may limit one's ability to offer suitable recommendations. While neurodegeneration is a recognized manifestation of CTX, there is scant literature to characterize the nature of cortical symptoms and even less detailing of its associated neurocognitive and neuropsychiatric manifestations.

METHOD

Based on the lack of representation of CTX in neuropsychological literature, we sought to present a case seen in a 39-year-old patient within our own clinic.

RESULTS

Evaluation of the patient's neurocognitive functioning revealed global impairment consistent with a CTX diagnosis and neuroimaging findings noting significant cerebellar involvement.

CONCLUSIONS

Neuropsychologists are increasingly called upon to make treatment recommendations and provide information that may be helpful in differential diagnosis as part of multidisciplinary teams. Referrals from neurology are common, and it is important for neuropsychologists to be aware of diseases that affect the central nervous system; CTX is one such example. The goal of this case study is to build awareness of this condition and increase interest in a more systematic approach to research and clinical care of this population.

Long-term treatment effect in cerebrotendinous xanthomatosis depends on age at treatment start

Objective

To evaluate the effect of chenodeoxycholic acid treatment on disease progression in cerebrotendinous xanthomatosis (CTX).

Methods

In this retrospective cohort study, we report the clinical long-term follow-up characteristics of 56 Dutch patients with CTX. Age at diagnosis was correlated with clinical characteristics and with the course of modified Rankin Scale (mRS) and Expanded Disability Status Scale (EDSS) scores at follow-up.

Results

Median follow-up time was 8 years (6 months–31.5 years). Patients diagnosed and treated before the age of 24 years had a significantly better outcome at follow-up. When considering only patients with a good treatment adherence (n = 43), neurologic symptoms, if present, disappeared in all patients who were diagnosed before the age of 24 and treated since. Furthermore, treatment prevented the development of new neurologic symptoms during follow-up. In contrast, 61% of the patients diagnosed and treated after the age of 24 showed deterioration of the neurologic symptoms, with parkinsonism as a treatment-resistant feature. There was an improvement or stabilization in favor of patients diagnosed and treated before the age of 24 compared to those treated after the age of 24: 100% vs 58% for mRS scores and 100% vs 50% for EDSS scores, respectively.

Conclusions

Treatment start at an early age can reverse and even prevent the development of neurologic symptoms in CTX. This study emphasizes the importance of early diagnosis in CTX and provides a rationale to include CTX in newborn screening programs.

Treatment with chenodeoxycholic acid in cerebrotendinous xanthomatosis: clinical, neurophysiological, and quantitative brain structural outcomes

BACKGROUND

Cerebrotendinous xanthomatosis (CTX) is a rare neurodegenerative disease related to sterols metabolism. It affects both central and peripheral nervous systems but treatment with chenodeoxycholic acid (CDCA) has been reported to stabilize clinical scores and improve nerve conduction parameters. Few quantitative brain structural studies have been conducted to assess the effect of CDCA in CTX.

METHODS AND RESULTS

We collected retrospectively clinical, neurophysiological, and quantitative brain structural data in a cohort of 14 patients with CTX treated by CDCA over a mean period of 5 years. Plasma cholestanol levels normalized under treatment with CDCA within a few months. We observed a significant clinical improvement in patients up to 25 years old, whose treatment was initiated less than 15 years after the onset of neurological symptoms. Conversely, patients whose treatment was initiated more than 25 years after neurological disease onset continued their clinical deterioration. Eleven patients presented with a length-dependent peripheral neuropathy, whose electrophysiological parameters improved significantly under CDCA. Volumetric analyses in a subset of patients showed no overt volume loss under CDCA. Moreover, diffusion weighted imaging showed improved fiber integrity of the ponto-cerebellar and the internal capsule with CDCA. CDCA was well tolerated in all patients with CTX.

CONCLUSION

CDCA may reverse the pathophysiological process in patients with CTX, especially if treatment is initiated early in the disease process. Besides tendon xanthoma, this study stresses the need to consider plasma cholestanol measurement in any patient with infantile chronic diarrhea and/or jaundice, juvenile cataract, learning disability and/or autism spectrum disorder, pyramidal signs, cerebellar syndrome or peripheral neuropathy.

Different phenotypes in identical twins with cerebrotendinous xanthomatosis: case series

Cerebrotendinous xanthomatosis (CTX) is a rare, genetically determined error of metabolism. The characteristic clinical symptoms are diarrhea, juvenile cataracts, tendon xanthomas and neuropsychiatric alterations. The aim of this study is to present a pair of identical adult twins with considerable differences in the severity of phenotype. With regards to neuropsychiatric symptoms, the predominant features were severe Parkinsonism and moderate cognitive dysfunctions in the more-affected individual, whereas these alterations in the less-affected patient were only very mild and mild, respectively. The characteristic increase in the concentrations of serum cholestanol and the lesion volumes in dentate nuclei in the brain assessed with magnetic resonance imaging were quite similar in both cases. The lifestyle conditions, including eating habits of the twin pair, were quite similar as well; therefore, currently unknown genetic modifiers or certain epigenetic factors may be responsible for the differences in severity of phenotype. This case series serves as the first description of an identical twin pair with CTX presenting heterogeneous clinical features.

Different phenotypes in identical twins with cerebrotendinous xanthomatosis: case series

Cerebrotendinous xanthomatosis (CTX) is a rare, genetically determined error of metabolism. The characteristic clinical symptoms are diarrhea, juvenile cataracts, tendon xanthomas and neuropsychiatric alterations. The aim of this study is to present a pair of identical adult twins with considerable differences in the severity of phenotype. With regards to neuropsychiatric symptoms, the predominant features were severe Parkinsonism and moderate cognitive dysfunctions in the more-affected individual, whereas these alterations in the less-affected patient were only very mild and mild, respectively. The characteristic increase in the concentrations of serum cholestanol and the lesion volumes in dentate nuclei in the brain assessed with magnetic resonance imaging were quite similar in both cases. The lifestyle conditions, including eating habits of the twin pair, were quite similar as well; therefore, currently unknown genetic modifiers or certain epigenetic factors may be responsible for the differences in severity of phenotype. This case series serves as the first description of an identical twin pair with CTX presenting heterogeneous clinical features.

Cerebrotendinous xanthomatosis, a metabolic disease with different neurological signs: two case reports

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive inborn error of bile acids synthesis and lipid accumulation caused by a deficiency of the mitochondrial cytochrome P450 sterol 27-hydroxylase enzyme encoded by CYP27A1. Pathogenic variants in CYP27A1 cause elevated cholestanol levels in the body, which leads to a variable clinical presentation that often includes cataracts, intellectual disability, neurological features, tendon xanthomas, and chronic diarrhea. Herein we describe the cases of two unrelated adult CTX patients. Case 1 is a patient with neurological dysfunction, including moderate intellectual disability, cataract of right eye, and xanthomas; Case 2 is a patient with tendon xanthomas without neurological symptoms. Plasma sterols profile obtained from both cases showed higher levels of cholestanol and cholesterol biosynthetic precursors compared to unaffected subjects. Case 1 and Case 2 were homozygous for the c.1263 + 5G > T (p.Leu396Profs29X) and c.1435C > G (p.Arg479Gly) pathogenic variants, respectively, in the CYP27A1 gene. Interestingly, for the first time, Case 2 variant has been identified in a homozygous state. Our results highlight that the sterol profile and genetic analyses are essential to make the diagnosis of CTX and to exclude other dyslipidemias.

Evaluation of cholesterol metabolism in cerebrotendinous xanthomatosis

BACKGROUND

Cerebrotendinous xanthomatosis (CTX) is a treatable bile acid disorder caused by mutations of CYP27A1. The pathogenesis of neurological damage has not been completely explained. Oral chenodeoxycholic acid (CDCA) can lead to clinical stabilization, but in a subgroup of patients the disease progresses despite treatment. In the present study, we aimed at clarifying cholesterol metabolism abnormalities and their response to CDCA treatment, in order to identify reliable diagnostic and prognostic markers and understand if differences exist between stable patients and those with neurological progression.

METHODS

We enrolled 19 untreated CTX patients and assessed serum profile of bile acids intermediates, oxysterols, cholesterol, lathosterol, and plant sterols. Then we performed a long-term follow up during CDCA therapy, and compared biochemical data with neurological outcome.

RESULTS

We observed increase of cholestanol, 7α-hydroxy-4-cholesten-3-one (7αC4), lathosterol, and plant sterols, whereas 27-hydroxycholesterol (27-OHC) was extremely low or absent. CDCA treatment at a daily dose of 750 mg normalized all biochemical parameters except for 7αC4 which persisted slightly higher than normal in most patients, and 27-OHC which was not modified by therapy. Biochemical evaluation did not reveal significant differences between stable and worsening patients.

DISCUSSION

Cholestanol and 7αC4 represent important markers for CTX diagnosis and monitoring of therapy. Treatment with CDCA should aim at normalizing serum 7αC4 as well as cholestanol, since 7αC4 better mirrors 7α-hydroxylation rate and is thought to be correlated with cholestanol accumulation in the brain. Assessment of serum 27-OHC is a very good tool for biochemical diagnosis at any stage of disease. Lathosterol and plant sterols should be considered as additional markers for diagnosis and monitoring of therapy. Further studies including long-term assessment of bile acid intermediates in cerebrospinal fluid are needed in patients who show clinical progression despite treatment.

TMS-induced motor evoked potentials in Wilson's disease: a systematic literature review

Wilson's disease (WD) is a metabolic brain disease resulting from improper copper metabolism. Although pyramidal symptoms are rarely observed, subclinical injury is highly possible as copper accumulates in all brain structures. The usefulness of motor evoked potentials (MEPs) in pyramidal tracts damage evaluation still appears to be somehow equivocal. We searched for original papers assessing the value of transcranial magnetic stimulation elicited MEPs with respect to motor function of upper and lower extremity in WD. We searched PubMed for original papers evaluating use of MEPs in WD using key words: "motor evoked potentials Wilson's disease" and "transcranial magnetic stimulation Wilson's disease." We found six articles using the above key words. One additional article and one case report were found while viewing the references lists. Therefore, we included eight studies. Number of patients in studies was low and their clinical characteristic was variable. There were also differences in methodology. Abnormal MEPs were confirmed in 20-70% of study participants. MEPs were not recorded in 7.6-66.7% of patients. Four studies reported significantly increased cortical excitability (up to 70% of patients). Prolonged central motor conduction time was observed in four studies (30-100% of patients). One study reported absent or prolonged central motor latency in 66.7% of patients. Although MEPs may be abnormal in WD, this has not been thoroughly assessed. Hence, further studies are indispensable to evaluate MEPs' usefulness in assessing pyramidal tract damage in WD.

Cerebrotendinous xanthomatosis: a comprehensive review of pathogenesis, clinical manifestations, diagnosis, and management

Cerebrotendinous xanthomatosis (CTX) OMIM#213700 is a rare autosomal-recessive lipid storage disease caused by mutations in the CYP27A1 gene; this gene codes for the mitochondrial enzyme sterol 27-hydroxylase, which is involved in bile acid synthesis. The CYP27A1 gene is located on chromosome 2q33-qter and contains nine exons. A CYP27A1 mutation leads to decreased synthesis of bile acid, excess production of cholestanol, and consequent accumulation of cholestanol in tissues. Currently there is no consensus on the prevalence of CTX, one estimate being <5/100,000 worldwide. The prevalence of CTX due to the CYP27A1 mutation R362C alone is approximately 1/50,000 in Caucasians. Patients with CTX have an average age of 35 years at the time of diagnosis and a diagnostic delay of 16 years. Clinical signs and symptoms include adult-onset progressive neurological dysfunction (i.e., ataxia, dystonia, dementia, epilepsy, psychiatric disorders,peripheral neuropathy, and myopathy) and premature non-neurologic manifestations (i.e., tendon xanthomas, childhood-onset cataracts, infantile-onset diarrhea, premature atherosclerosis, osteoporosis, and respiratory insufficiency). Juvenile cataracts, progressive neurologic dysfunction, and mild pulmonary insufficiency are unique symptoms that distinguish CTX from other lipid storage disorders including familial dysbetalipoproteinemia, homozygous familial hypercholesterolemia, and sitosterolemia, all of which might also present with xanthomas and cardiovascular diseases. Brain magnetic resonance imaging (MRI) shows bilateral lesions in the dentate nucleus of the cerebellum and mild white matter lesions. The classical symptoms and signs, namely elevated levels of cholestanol and bile alcohols in serum and urine, brain MRI, and the mutation in the CYP27A1 gene confirm the diagnosis of CTX. Early diagnosis and long-term treatment with chenodeoxycholic acid (750 mg/d) improve neurological symptoms and contribute to a better prognosis.

Neurological outcome in cerebrotendinous xanthomatosis treated with chenodeoxycholic acid: early versus late diagnosis

OBJECTIVE

To present the long-term neurological outcome of Jewish Israeli patients with cerebrotendinous xanthomatosis (CTX) after several years of chenodeoxycholic acid (CDCA) treatment.

METHODS

A cross sectional observational study of all patients with a diagnosis of CTX followed in a referral outpatient clinic during the years 2003-2012.

RESULTS

Eighteen patients (10 men) from 11 families were enrolled. Sixteen patients were included in the analysis (2 patients had low compliance for treatment). The mean ± SD age at last evaluation was 35.0 ± 9.2 years (range, 16-45 years). After their diagnosis, at age 22.6 ± 10.8 years, all patients were treated with CDCA. Patients who started treatment after the age of 25 years had worse outcome and were significantly more limited in ambulation (P = 0.004) and more cognitively impaired (P = 0.047). Five patients who started treatment after 25 years of age continued to deteriorate despite CDCA treatment.

CONCLUSIONS

Beginning CDCA treatment as early as possible is crucial to preventing neurological damage and deterioration in CTX. After significant neurological pathology is established, the effect of treatment is limited and deterioration may continue.

A suspicion index for early diagnosis and treatment of cerebrotendinous xanthomatosis

BACKGROUND

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder characterized by a heterogeneous presentation and a broad spectrum of clinical manifestations. Since early diagnosis and replacement therapy with chenodeoxycholic acid can prevent clinical deterioration, our aim was to develop a diagnostic tool to identify and treat CTX patients at an initial stage of the disease.

METHODS

We devised a suspicion index, composed of weighted scores assigned to indicators such as family history characteristics and common systemic and neurological features, on the basis of a pooled analysis of selected international CTX series. The indicators were classified as very strong (score 100), strong (50) or moderate (25). The suspicion index was then applied retrospectively to our CTX population.

RESULTS

Early systemic signs such as cataract, diarrhea and neonatal cholestatic jaundice were considered strong indicators, together with neurological features such as intellectual impairment, psychiatric disturbances, ataxia, spastic paraparesis and dentate nuclei abnormalities at MRI. Tendon xanthomas were regarded as very strong indicators, as was an affected sibling. A total score ≥ 100 warranted serum cholestanol assessment. Elevated cholestanol or a total score ≥ 200, with one very strong or four strong indicators, warranted CYP27A1 gene analysis. In our patients, age at diagnosis was 35.5 ± 11.8 years (mean ± standard deviation), whereas with the diagnostic tool it became 10.6 ± 9.8 years (p < 0.01).

CONCLUSIONS

Our suspicion index provides a simple and inexpensive diagnostic tool allowing diagnosis and treatment of CTX before neurological disability occurs.

Acute thyrotoxic bulbar myopathy with encephalopathic behaviour: an uncommon complication of hyperthyroidism

Objective. Acute thyrotoxic bulbar palsy is rare, severe, and rapidly progressive. We describe a case of thyrotoxicosis with bulbar palsy, encephalopathy, and pyramidal tract dysfunction. Case Report. 64-year-old white male with toxic multinodular goiter presented with rapid atrial fibrillation. He had mild tremor, normal cranial nerve examination, 4/5 strength in all extremities, normal reflexes, and down going plantars. TSH was low at 0.09 (normal: 0.34–5.6 uIU/mL), and free T4 was high at 5.22 (normal: 0.47–1.41 ng/dL). Despite optimal AV nodal blockade, he had persistent rapid atrial fibrillation. He later developed cervical dystonia, rigidity, clonus, dysarthria, dysphagia, vocal cord palsy, and absent gag reflex. Thyroid storm was suspected. Neuroimaging and cerebrospinal fluid cultures were nondiagnostic. Acetylcholine receptor antibodies were negative. Swallow ability was impaired with heavy secretions. Remarkable improvement in symptoms was noted after initiation of treatment for thyroid storm. Conclusion. Pyramidal tract symptoms and bulbar palsy may occur with thyrotoxicosis. Cranial nerve involvement and encephalopathy raise a question of primary brain mechanism causing bulbar palsy. This is reversible with prompt treatment of thyroid storm.

Long-term bone density evaluation in cerebrotendinous xanthomatosis: evidence of improvement after chenodeoxycholic acid treatment

Cerebrotendinous xanthomatosis (CTX) is known to be associated with osteoporosis and a higher incidence of bone fractures. However, the underlying pathogenesis is still unknown, and the effects of long-term replacement therapy with chenodeoxycholic acid (CDCA) on bone mineral density (BMD) have not been fully investigated. We studied 11 CTX patients aged 13-43 years. We performed dual-energy X-ray absorptiometry and assessed serum cholestanol and 25-hydroxyvitamin D (25-OHD) concentrations both at the time of diagnosis and after long-term treatment with CDCA. At baseline, we found low BMD in nine patients, cholestanol elevation in all subjects, and 25-OHD decrease in nine. After a mean follow-up time of 30 months (range 24-36), no substantial clinical changes including bone fractures occurred; and we detected a significant increase of both planar and volumetric BMD as well as normalization of plasma cholestanol levels and increase of serum 25-OHD. Densitometric improvement following CDCA introduction was not correlated to changes of biochemical parameters. Our study confirms the presence of low bone mass in CTX and demonstrates that long-term CDCA treatment increases bone mineral content. In this respect, improvement of vitamin D intestinal absorption secondary to bile acid restoration could play an important role. Moreover, our data strongly suggest the utility of periodic bone density evaluation in CTX patients.

Polyneuropathy in cerebrotendinous xanthomatosis and response to treatment with chenodeoxycholic acid

Polyneuropathy has been reported in cerebrotendinous xanthomatosis (CTX), although its nature and possible association with certain genotypes and phenotypes are unclear. The effect of chronic administration of chenodeoxycholic acid (CDCA) on peripheral nerve conduction parameters is still debated. We report clinical, laboratory, and electrophysiological findings in 35 CTX patients. Twenty-six subjects (74.2 %) showed peripheral nerve abnormalities. Polyneuropathy was predominantly axonal (76.9 % of patients) and generally mild. No correlation was found between its presence and clinical or biochemical data. In polyneuropathic patients, CDCA treatment improved electrophysiological conduction parameters, irrespective of the duration of therapy. Improvement mainly concerned nerve conduction velocities, whereas most nerve amplitudes remained unchanged. This means that CDCA treatment did not influence the number of axons activated by maximum electrical stimulation but increased the conduction of the still-excitable fibers. Our findings may suggest that CDCA treatment promotes myelin synthesis in nerve fibers with residual unaffected axons. The effect of therapy may therefore depend largely on the extent of irreversible structural damage to axons.

Polyneuropathy in cerebrotendinous xanthomatosis and response to treatment with chenodeoxycholic acid

Polyneuropathy has been reported in cerebrotendinous xanthomatosis (CTX), although its nature and possible association with certain genotypes and phenotypes are unclear. The effect of chronic administration of chenodeoxycholic acid (CDCA) on peripheral nerve conduction parameters is still debated. We report clinical, laboratory, and electrophysiological findings in 35 CTX patients. Twenty-six subjects (74.2 %) showed peripheral nerve abnormalities. Polyneuropathy was predominantly axonal (76.9 % of patients) and generally mild. No correlation was found between its presence and clinical or biochemical data. In polyneuropathic patients, CDCA treatment improved electrophysiological conduction parameters, irrespective of the duration of therapy. Improvement mainly concerned nerve conduction velocities, whereas most nerve amplitudes remained unchanged. This means that CDCA treatment did not influence the number of axons activated by maximum electrical stimulation but increased the conduction of the still-excitable fibers. Our findings may suggest that CDCA treatment promotes myelin synthesis in nerve fibers with residual unaffected axons. The effect of therapy may therefore depend largely on the extent of irreversible structural damage to axons.

Miscellaneous non-inflammatory musculoskeletal conditions. Rare thesaurismosis and xanthomatosis

The focus will be on xanthomatosis, a tissue danger signal which needs to be recognized by the clinician, and its relationship with monogenetic lipoprotein disorders (cholesterol, triglycerides), bile acid and sterol metabolism, particularly on metabolic pathways and genetics as well as on musculoskeletal and cardiovascular involvement, and their implications for clinical management. The critical question is to assess coronary heart disease risk, requiring correct identification of the pattern of lipoprotein disorders and of the causes (primary or secondary). Familial hypercholesterolemia must be suspected in adults and children with raised total cholesterol, especially when there is a personal or a family history of premature coronary heart disease, usually requiring potent statins to achieve adequate LDL-cholesterol lowering, even if we do not know safety of long-term therapy and whether treatments of dyslipidemia early in life prevent cardiovascular diseases in adulthood. Cerebrotendinous xanthomatosis is a treatable disease and must be suspected if there is a history of infantile chronic diarrhea and/or juvenile cataracts, even in the absence of tendon xanthomas. Current evidence for the prevention and screening, diagnosis, and treatment of dyslipidemia are available for the clinicians.