A novel ABCD1 gene mutation causes adrenomyeloneuropathy presenting with spastic paraplegia: A case report

RATIONALE

X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene leading to very long chain fatty acid (VLCFA) accumulation. The disease demonstrates a spectrum of phenotypes including adrenomyeloneuropathy (AMN). We aimed to identify the genetic basis of disease in a patient presenting with AMN features in order to confirm the diagnosis, expand genetic knowledge of ABCD1 mutations, and elucidate potential genotype-phenotype associations to inform management.

PATIENT CONCERNS

A 29-year-old male presented with a 4-year history of progressive spastic paraplegia, weakness of lower limbs, fecal incontinence, sexual dysfunction, hyperreflexia, and positive Babinski and Chaddock signs.

DIAGNOSES

Neuroimaging revealed brain white matter changes and spinal cord thinning. Significantly elevated levels of hexacosanoic acid (C26:0) and tetracosanoic acid (C24:0) suggested very long chain fatty acids (VLCFA) metabolism disruption. Genetic testing identified a novel hemizygous ABCD1 mutation c.249dupC (p.F83fs). These findings confirmed a diagnosis of X-linked ALD with an AMN phenotype.

INTERVENTIONS

The patient received dietary counseling to limit VLCFA intake. Monitoring for adrenal insufficiency and consideration of Lorenzo's oil were advised. Genetic counseling and testing were offered to at-risk relatives.

OUTCOMES

At present, the patient continues to experience progressive paraplegia. Adrenal function remains normal thus far without steroid replacement. Family members have undergone predictive testing.

LESSONS

This case expands the known mutation spectrum of ABCD1-linked X-ALD, providing insight into potential genotype-phenotype correlations. A thoughtful diagnostic approach integrating clinical, biochemical and genetic data facilitated diagnosis. Findings enabled genetic counseling for at-risk relatives regarding this X-linked disorder.

Adrenomyeloneuropathy manifesting as adrenal insufficiency and bilateral lower extremity spastic paraplegia: A case report and literature review

RATIONALE

Adrenomyeloneuropathy (AMN) is a variant type of X-linked adrenoleukodystrophy, and it is a genetic metabolic disease with strong clinical heterogeneity so that it is easily misdiagnosed and underdiagnosed. Moreover, most patients with AMN have an insidious clinical onset and slow progression. Familiarity with the pathogenesis, clinical features, diagnosis, and treatment of AMN can help identify the disease at an early stage.

PATIENT CONCERNS

We present a case of 35-year-old male, who was admitted to our hospital due to "immobility of the lower limbs for 2 years and worsening for half a year," accompanied by skin darkening and hyperpigmentation of lips, oral mucosa, and areola since puberty.

DIAGNOSIS

The level of very long-chain fatty acids was high and genetic testing depicted that exon 1 of the ABCD1 gene had a missense mutation of C.761c>T, which was diagnosed as AMN.

INTERVENTIONS

Baclofen was administered to improve muscle tension combined with glucocorticoid replacement therapy.

OUTCOMES

The condition was relieved after half a year.

LESSONS

The clinical manifestations of AMN are diverse. When patients with adrenocortical dysfunction complicated with progressive spastic paraplegia of lower limbs are involved, AMN should be highly suspected, and the determination of very long-chain fatty acids and genetic testing should be performed as soon as possible to confirm the diagnosis because early treatment can help prevent or delay the progression of the disease.

Cerebral X-linked Adrenoleukodystrophy Presenting As Enlarging Cavum Vergae Cyst: A Case Report

The cavum vergae cyst (CVC) is an uncommon brain malformation. Most patients with CVC are asymptomatic and do not require neurosurgical intervention. Separately, cerebral X-linked adrenoleukodystrophy (X-ALD) is one of the phenotypes of a genetic peroxisomal disorder that is seldom managed by neurosurgeons. We report an unusual case of cerebral X-ALD presenting as an enlarging CVC in a child, and discuss its nuances in corroboration with the literature. A previously well six-year-old male presented with confusion and fever. Urgent neuroimaging demonstrated a large CVC with resultant hydrocephalus. Of note, there were symmetrical areas of signal changes in the periventricular white matter bilaterally involving the corpus callosum, thalami, cerebral peduncles, midbrain, and pons in his MRI. Further investigations performed as part of his medical workup reported high plasma concentrations of very long-chain fatty acids (VLCFA). Put together, a diagnosis of cerebral X-ALD was confirmed. Initially, an external ventricular drain was inserted directly into the CVC under stereotaxy to decompress it. Subsequently, endoscopic fenestration of the CVC was performed as the definitive treatment. He recovered uneventfully from the neurosurgical interventions and proceeded for the treatment of his cerebral X-ALD. To our knowledge, this is the first report of cerebral X-ALD presenting as a CVC in a patient. This case adds to the limited literature for both rare conditions and highlights the importance of a multidisciplinary approach to management.

Case report of dysregulation of primary bile acid synthesis in a family with X-linked adrenoleukodystrophy

RATIONALE

X-linked adrenoleukodystrophy (X-ALD) is a rare disorder caused by mutations in the ABCD1 gene, coding for peroxisomal membrane transporter adrenoleukodystrophy (ALD) protein. The disease is characterized by accumulation of very long chain fatty acids (VLCFAs) in tissues. Adult adrenomyeloneuropathy (AMN) and the cerebral inflammatory form of ALD are the main phenotypes presenting various symptoms.

PATIENT CONCERNS

We report a case of 37-year-old patient with diagnosis of X-ALD, confirmed based on elevated VLCFA concentrations and genetic testing of ABCD1 gene. The complete clinical picture in the patient indicates AMN phenotype with cerebral involvement.

DIAGNOSES

The reduced synthesis of unconjugated cholic and chenodeoxycholic acids, and the reduction to 28% to 29% of peroxisomal beta-oxidation of behenic acid and normal peroxisomal metabolism of pristanic and palmitic acid were observed in the X-ALD patient. Sanger sequencing of major genes involved in primary bile acid (BA) synthesis failed to identify pathogenic mutations of the investigated set of genes.

INTERVENTIONS

Plasma concentrations of BAs, VLCFAs, and beta-oxidation of C22:0, C16:0, and pristanic acid were studied in primary skin fibroblasts of the patient. In addition, we performed sequencing of the ABCD1, ABCD3, CYP7A1, CYP7B1, CYP27A1, HSD3B7, AKR1D1, and SLC27A5 genes in the X-ALD family.

OUTCOMES

In the Polish family affected with AMN a dysregulation of the primary BA synthesis pathway was found.

LESSONS

We have demonstrated the coincidence of the adult form of X-ALD with abnormalities in BA synthesis. We suggest that decreased synthesis of BAs may be an additional dysfunction as a consequence of the ABCD1 c.659T>C, p.(Leu220Pro) mutation and may be further evidence that disturbed cholesterol metabolism is important in the pathology of ALD.

A novel mutation in the ABCD1 gene of a Chinese patient with X-linked adrenoleukodystrophy: Case report

RATIONALE

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder, which is inherited as an X-linked recessive trait. ATP binding cassette subfamily D member 1 (ABCD1) localized to Xq28 is the only gene associated with ALD.

PATIENT CONCERNS

We report a case of Chinese boy with childhood cerebral ALD, who began experiencing symptoms at the age of 5 years and 2 months. Very long chain fatty acids analysis revealed high levels of C24/C22 ratio and C26/C22 ratio in the plasma. Magnetic resonance imaging (MRI) showed abnormal bilateral white matter lesions in brainstem, temporal, occipital, and parietal lobes.

DIAGNOSES

Direct sequencing of the ABCD1 gene identified a novel c.1502del mutation on exon 6, which causes a substitution of the 501st amino acid from methionine to serine and finally the 557th codon is changed to stop codon.

INTERVENTIONS

Special education and rehabilitation therapy.

OUTCOMES

The disease progressed rapidly and resulted in death at the age of 8 years.

LESSONS

Early detection of mutations in the ABCD1 gene may facilitate diagnosis, genetic counseling and potentially aid prenatal diagnosis of the disease.

Unusual brain images of a boy with adolescent cerebral X-linked adrenoleukodystrophy presenting with exhibitionism: A CARE-compliant case report

RATIONALE

The respective involvements of both the thalamus and exhibitionism in cerebral X-linked adrenoleukodystrophy (X-ALD) have not been reported.

PATIENT CONCERNS

An 11-year-old boy initially presented with exhibitionism and progressive neurobehavioral symptoms. He subsequently developed transient urinary and fecal incontinence, and an unwillingness to eat or communicate.

DIAGNOSES

We conducted contrast-enhanced brain magnetic resonance imaging (MRI), which revealed symmetrical altered signal intensities in bilateral frontal white matter, the basal ganglia, and dorsal thalami, as well as a peripheral rim of contrast enhancement. Diagnosis of adolescent cerebral X-ALD was confirmed on the basis of next generation genetic sequencing analysis.

INTERVENTIONS

We initiated the patient on hormonal replacement therapy.

OUTCOMES

We observed rapidly progressive neurologic deterioration in this patient, and the boy fell into a vegetative state 10 months after discharge.

LESSONS

We recommend that physicians should not disregard X-ALD in patients with isolated psychiatric symptoms, including hypersexual behavior. The combination of detailed clinical evaluation, MRI, and next generation genetic sequencing can expedite the diagnostic process of atypical variant of X-ALD.

The genetically modified polysialylated form of neural cell adhesion molecule-positive cells for potential treatment of X-linked adrenoleukodystrophy

PURPOSE

Cell transplantation of myelin-producing exogenous cells is being extensively explored as a means of remyelinating axons in X-linked adrenoleukodystrophy. We determined whether 3,3',5-Triiodo-L-thyronine (T3) overexpresses the ABCD2 gene in the polysialylated (PSA) form of neural cell adhesion molecule (NCAM)-positive cells and promotes cell proliferation and favors oligodendrocyte lineage differentiation.

MATERIALS AND METHODS

PSA-NCAM+ cells from newborn Sprague-Dawley rats were grown for five days on uncoated dishes in defined medium with or without supplementation of basic fibroblast growth factor (bFGF) and/or T3. Then, PSA-NCAM+ spheres were prepared in single cells and transferred to polyornithine/fibronectin-coated glass coverslips for five days to determine the fate of the cells according to the supplementation of these molecules. T3 responsiveness of ABCD2 was analyzed using real-time quantitative polymerase chain reaction, the growth and fate of cells were determined using 5-bromo-2-deoxyuridine incorporation and immunocytochemistry, respectively.

RESULTS

Results demonstrated that T3 induces overexpression of the ABCD2 gene in PSA-NCAM+ cells, and can enhance PSA-NCAM+ cell growth in the presence of bFGF, favoring an oligodendrocyte fate.

CONCLUSION

These results may provide new insights into investigation of PSA-NCAM+ cells for therapeutic application to X-linked adrenoleukodystrophy.

Oxidative stress modulates mitochondrial failure and cyclophilin D function in X-linked adrenoleukodystrophy

A common process associated with oxidative stress and severe mitochondrial impairment is the opening of the mitochondrial permeability transition pore, as described in many neurodegenerative diseases. Thus, inhibition of mitochondrial permeability transition pore opening represents a potential target for inhibiting mitochondrial-driven cell death. Among the mitochondrial permeability transition pore components, cyclophilin D is the most studied and has been found increased under pathological conditions. Here, we have used in vitro and in vivo models of X-linked adrenoleukodystrophy to investigate the relationship between the mitochondrial permeability transition pore opening and redox homeostasis. X-linked adrenoleukodystrophy is a neurodegenerative condition caused by loss of function of the peroxisomal ABCD1 transporter, in which oxidative stress plays a pivotal role. In this study, we provide evidence of impaired mitochondrial metabolism in a peroxisomal disease, as fibroblasts in patients with X-linked adrenoleukodystrophy cannot survive when forced to rely on mitochondrial energy production, i.e. on incubation in galactose. Oxidative stress induced under galactose conditions leads to mitochondrial damage in the form of mitochondrial inner membrane potential dissipation, ATP drop and necrotic cell death, together with increased levels of oxidative modifications in cyclophilin D protein. Moreover, we show increased expression levels of cyclophilin D in the affected zones of brains in patients with adrenomyeloneuropathy, in spinal cord of a mouse model of X-linked adrenoleukodystrophy (Abcd1-null mice) and in fibroblasts from patients with X-linked adrenoleukodystrophy. Notably, treatment with antioxidants rescues mitochondrial damage markers in fibroblasts from patients with X-linked adrenoleukodystrophy, including cyclophilin D oxidative modifications, and reverses cyclophilin D induction in vitro and in vivo. These findings provide mechanistic insight into the beneficial effects of antioxidants in neurodegenerative and non-neurodegenerative cyclophilin D-dependent disorders.