[Cerebrotendinous xanthomatosis: a multicentric retrospective study of 15 adults, clinical and paraclinical typical and atypical aspects]

Clinical, electrophysiological, and genetic characteristics of cerebrotendinous xanthomatosis in South Korea

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder caused by 27-hydroxylase deficiency. We report the clinical characteristics of six Korean CTX patients. The median age of onset was 22.5 years, the median age at diagnosis was 42 years, and the diagnostic delay was 18.1 years. The most common clinical symptoms were tendon xanthoma and spastic paraplegia. Four of five patients exhibited latent central conduction dysfunction. All patients carried the same mutation in CYP27A1 (c.1214 G>A [p.R405Q]). CTX is a treatable neurodegenerative disorder; however, our results revealed that patients with CTX in Korea might receive the diagnosis after a prolonged delay.    .

Update on Neuropathies in Inborn Errors of Metabolism

Neuropathies are relatively common in inborn errors of metabolism (IEMs); however, due to the early onset and severe, progressive course of many IEMs, they have not been very well researched yet. This article aims to review and compare neuropathies in inborn errors of metabolism, mostly with childhood and juvenile onset. Some of these diseases are treatable if diagnosed early and in many cases, the therapy can not only slow down disease progression, but can also reverse the changes already made by the condition.

Update on cerebrotendinous xanthomatosis

PURPOSE OF REVIEW

Cerebrotendinous xanthomatosis (CTX) is a rare genetic lipid storage disorder with highly pleomorphic clinical phenotype. Complications of this disease can be devastating and may include severe cognitive impairment and dementia in later stages. Disease progression can be prevented or stabilized by bile acid replacement therapy, although a subset of patients with advanced disease continue to deteriorate despite therapy.

RECENT FINDINGS

Delayed diagnosis of CTX continues to impede effective treatment. A clinical diagnostic algorithm for CTX was developed that can decrease the age of diagnosis of CTX. The strategy of screening children with bilateral juvenile cataracts for CTX also improved diagnosis, as this group had a 500-fold higher-rate of CTX than the general population. Improved diagnosis of CTX is critical, as patients treated early in the course of the disease have significantly better outcomes compared with those treated later. More sensitive and specific biochemical testing for CTX has been developed that is potentially more informative than blood cholestanol to assess treatment efficacy and medication compliance in CTX.

SUMMARY

Because we are recognizing more severe presentations of CTX in infants and children, and delayed diagnosis and treatment worsens the prognosis, CTX is an excellent candidate disorder for newborn screening using recently reported methods for newborn dried bloodspot analysis.

The spectrum of magnetic resonance findings in cerebrotendinous xanthomatosis: redefinition and evidence of new markers of disease progression

Cerebrotendinous xanthomatosis (CTX) is a metabolic disease characterized by systemic signs and neurological impairment, which can be prevented if chenodeoxycholic acid (CDCA) treatment is started early. Despite brain MRI represents an essential diagnostic tool, the spectrum of findings is worth to be reappraised, and follow-up data are needed. We performed clinical evaluation and brain MRI in 38 CTX patients. Sixteen of them who were untreated at baseline examination underwent clinical and MRI follow-up after long-term treatment with CDCA. Brain MRI abnormalities included cortical and cerebellar atrophy, and T2W/FLAIR hyperintensity involving subcortical, periventricular, and cerebellar white matter, the brainstem and the dentate nuclei. Regarding the dentate nuclei, we also observed T1W/FLAIR hypointensity consistent with cerebellar vacuolation and T1W/FLAIR/SW hypointense alterations compatibly with calcification in a subgroup of patients. Long-term follow-up showed that clinical and neuroradiological stability or progression were almost invariably associated. In patients with cerebellar vacuolation at baseline, a worsening over time was observed, while subjects lacking vacuoles were clinically and neuroradiologically stable at follow-up. The brains of CTX patients very often show both supratentorial and infratentorial abnormalities at MRI, the latter being related to clinical disability and including a wide spectrum of dentate nuclei alterations. The presence of cerebellar vacuolation may be regarded as a useful biomarker of disease progression and unsatisfactory response to therapy. On the other hand, the absence of dentate nuclei signal alteration should be considered an indicator of better prognosis.

The spectrum of magnetic resonance findings in cerebrotendinous xanthomatosis: redefinition and evidence of new markers of disease progression

Cerebrotendinous xanthomatosis (CTX) is a metabolic disease characterized by systemic signs and neurological impairment, which can be prevented if chenodeoxycholic acid (CDCA) treatment is started early. Despite brain MRI represents an essential diagnostic tool, the spectrum of findings is worth to be reappraised, and follow-up data are needed. We performed clinical evaluation and brain MRI in 38 CTX patients. Sixteen of them who were untreated at baseline examination underwent clinical and MRI follow-up after long-term treatment with CDCA. Brain MRI abnormalities included cortical and cerebellar atrophy, and T2W/FLAIR hyperintensity involving subcortical, periventricular, and cerebellar white matter, the brainstem and the dentate nuclei. Regarding the dentate nuclei, we also observed T1W/FLAIR hypointensity consistent with cerebellar vacuolation and T1W/FLAIR/SW hypointense alterations compatibly with calcification in a subgroup of patients. Long-term follow-up showed that clinical and neuroradiological stability or progression were almost invariably associated. In patients with cerebellar vacuolation at baseline, a worsening over time was observed, while subjects lacking vacuoles were clinically and neuroradiologically stable at follow-up. The brains of CTX patients very often show both supratentorial and infratentorial abnormalities at MRI, the latter being related to clinical disability and including a wide spectrum of dentate nuclei alterations. The presence of cerebellar vacuolation may be regarded as a useful biomarker of disease progression and unsatisfactory response to therapy. On the other hand, the absence of dentate nuclei signal alteration should be considered an indicator of better prognosis.

A practical approach to diseases affecting dentate nuclei

A wide variety of diseases affect the dentate nuclei. When faced with the radiological demonstration of signal changes in the dentate nuclei, radiologists and clinical neurologists have to sieve through the many possibilities, which they do not encounter on a regular basis. This task can be challenging, and therefore, developing a clinical, radiological, and laboratory approach is important. Information on the topic is scattered and the subject has not yet been reviewed. In this review, a combined clinicoradiological approach is presented. The signal changes in T1, T2, fluid-attenuated inversion recovery (FLAIR), diffusion, susceptibility weighted, and gadolinium-enhanced images can give specific or highly suggestive patterns, which are illustrated. The role of computed tomography (CT) in the diagnostic process is discussed. Specific radiological patterns do not exist in a significant proportion of patients where the clinical and laboratory analysis becomes important. In this review, we group the clinical constellations to narrow down the differential diagnosis and highlight the diagnostic clinical signs, such as tendon xanthomas and Kayser-Fleischer rings. As will be seen, a number of these conditions are potentially reversible, and hence, their early diagnosis is desirable. Finally, key diagnostic tests and available therapies are outlined. The practical approach thus begins with the radiologist and winds its way through the clinician, towards carefully selected diagnostic tests defining the therapy options.

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.