Cerebrotendinous Xanthomatosis, a Treatable Disorder Often Missed: Case Series of Three Patients Confirmed by Genetic Testing.

ABSTRACT: Cerebrotendinous xanthomatosis (CTX) is a treatable autosomal recessive disorder with varied clinical manifestations and age of onset and is often diagnosed late. We report three cases of CTX who presented at our center with clinical features of frequent diarrhea, early cataracts, xanthomas, cognitive decline, ataxia, neuropathy, and other manifestations of CTX. Magnetic resonance imaging (MRI) brain in all three patients revealed abnormalities consistent with CTX. Diagnosis was confirmed by next-generation sequencing. Chenodeoxycholic acid (CDCA) is recommended as the drug of choice, as it can halt the disease progression and reverse some of the symptoms. In addition to late diagnosis, nonavailability of CDCA in our part of world adds to the problem of management of such patients; therefore, they are often started on alternative therapies, which are less effective.

Cerebrotendinous xanthomatosis: a rare disorder with a rare presentation.

A young man was brought for mental retardation, frequent non-bloody diarrhoea and swellings at ankles and elbow. He became bed-ridden due to cataract, mental retardation and pain in the back and lower limb. There were repeated pathological fractures and vitamin D deficiency without renal dysfunction. There were low low-density lipoprotein and triglyceride levels. MRI of the brain revealed hypointense lesions in cerebellar white matter, heterogenous hyperintensity in dentate nucleus and adjacent white matter, right basal ganglia and in the periventricular region with diffuse cerebral atrophy. T1-weighted MRI (ankle region) revealed bilaterally thickened and irregular achilles tendons with hyperintense masses surrounded by patchy hypointensities. A similar xanthomatous lesion (cholestanol deposits) was also present in the sacral region. Vitamin D and calcium supplementation and chenodeoxycholic acid therapy improved pain at lower limbs and body weight. Cerebrotendinous xanthomatosis is a rare autosomal-recessive familial mutation of the sterol 27 hydroxylase causing lipid metabolic disease.

Could steroids mask the diagnosis of cerebrotendinous xanthomatosis?

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder of bile acid synthesis, caused by impaired hydroxylation of cholesterol side chains due to deficiency of the mitochondrial enzyme sterol 27-hydroxylase (CYP27A1), leading to accumulation of cholestanol and cholesterol in brain and other tissues. Elevated plasma cholestanol serves as a key marker for the clinical diagnosis of CTX. In the present report we describe a young man with CTX who was on high dose steroids for a misdiagnosed chronic inflammatory demyelinating polyneuropathy (CIDP) and had normal level of serum cholestanol. When steroids were discontinued, markedly elevated serum cholestanol was measured concomitant with marked clinical worsening. This observation may imply that steroids can lower plasma cholestanol, possibly by directly inducing residual CYP27A1 activity or by inducing alternative pathways for cholestanol elimination.