Cerebrotendinous xanthomatosis: report of a case

First case series of Polish patients with cerebrotendinous xanthomatosis and systematic review of cases from the 21st century

Cerebrotendinous xanthomatosis (CTX) is an inborn error of metabolism caused by recessive variants in the cytochrome P450 CYP27A1 gene. CTX is said to manifest with childhood-onset chronic diarrhea and the classic triad of juvenile-onset cataracts, Achilles tendons xanthomas, and progressive ataxia. It is currently one of the few inherited neurometabolic disorders amenable to a specific treatment. The diagnosis may be significantly delayed resulting in permanent neurological impairment. A retrospective review of the clinical characteristics and diagnostic findings in case series of six Polish patients with CTX. Additional retrospective review of symptoms and pathogenic variants of 568 CTX available cases and case series from the past 20 years. To the best of our knowledge, this is the widest review of CTX cases reported in years 2000-2021. We report the largest cohort of Polish patients ever published, with the identification of two hot-spot mutations. During the review of available 568 cases, we found significant differences in the clinical phenotypes and the localization of variants within the gene between Asian and non-Asian populations. These findings may facilitate molecular testing in the Polish and Asian populations. Invariably better screening for CTX and wider awareness is needed.

Cerebrotendinous xanthomatosis in a Hong Kong Chinese kinship with a novel splicing site mutation IVS6-1G>T in the sterol 27-hydroxylase gene

We reported a Hong Kong Chinese proband with Cerebrotendinous Xanthomatosis in which a novel acceptor splicing site mutation (IVS6-1G>T) was identified. Family screening revealed the same mutation in his elder brother and the youngest sister. All the three affected siblings were compound heterozygous for IVS6-1G>T and a known missense mutation R372Q (GenBank Accession No. M62401). Significant phenotypic variation was noted among them that the youngest sister was still symptom-free at the time of writing.

Plexiform xanthomatous tumor: a report of 20 cases in 12 patients

We present 12 patients with 20 plexiform xanthomatous tumors (PXTs). All patients were male. Patient ages ranged from 20 to 59 years (mean 45 years). Clinical information was available for 11 (92%) patients. Only one patient with markedly elevated cholesterol levels had a family history of hypercholesterolemia; none of the others had a family or personal history of diabetes mellitus, hypercholesterolemia, or hyperlipoproteinemia. Three patients had markedly elevated serum triglyceride levels. The tumors were solitary in seven patients and multiple in five patients: three patients had two tumors, one presented had three, and one had four. PXTs were located on the knee (n = 8), elbow (n = 5), foot or hand (n = 3), and one each on the Achilles tendon, buttock, toe, and back. PXT was white to yellow in color and ranged in size from 0.7 to 5 cm (mean 2.7 cm). The tumors were located in the dermis and subcutis, had a distinctive plexiform arrangement, and were composed of various admixtures of uniform epithelioid and xanthomatous cells. All tumors in patients with solitary or multiple lesions had a plexiform architecture. Most of the nodules of the plexiform pattern of PXTs measured 0.5-2 mm. Rarely cholesterol clefts, necrosis, sparse inflammation, and multinucleated Touton giant cells were present. In two patients with multiple tumors, the PXT completely lacked the xanthoma cells and thus resembled an epithelioid lesion. Immunohistochemically, all lesions were KP1 (CD68) and vimentin positive and lysozyme, S-100 protein, HMB-45, epithelial membrane antigen, cytokeratins, factor VIIIrag, CD34, muscle-specific actin, alpha-smooth muscle actin, desmin (D33), desmin (Der-11), chromogranin, synaptophysin, neurofilament protein, and glial fibrillary acidic protein negative. Two patients with multiple lesions noted recurrences over 10 years. With the exception of one patient who died of an unknown cause, all 10 patients with follow-up were alive, some with residual disease, over a mean of 9 years (range 1-25 years). Some PXTs may represent a morphologic variant of tuberous or tendinous xanthoma, yet its exclusive occurrence in men, absence of personal/familial hyperlipemia/hypercholesterolemia in some patients, and relative paucity of inflammation and cholesterol clefts may make this a distinctive entity.

Cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis is a rare autosomal recessive lipid-storage disease caused by mutations in the sterol 27-hydroxylase gene. The accumulation of cholestanol in various tissues characterizes this disease. Diagnosis is based on determination of urinary bile alcohols. Therapy with chenodeoxycholic acid may arrest the progression of the disease. A 55-year-old woman presented with a slowly progressive paraparesia and two firm subcutaneous tumors over the knees. Her medical history revealed difficulty in standing and walking since infancy, bilateral juvenile cataracts, and mental retardation. Histopathologic examination of one subcutaneous tumor was consistent with tendinous xanthoma. Substantial elevation of urinary bile alcohols confirmed the diagnosis. Treatment with oral chenodeoxycholic acid was started, with only mild improvement of spasticity. Recognition of tendon xanthomas in a young patient with neurologic symptoms or cataracts (or both) is crucial to start early treatment and to avoid irreversible neurologic sequelae.