X-linked ALD Research Articles

Selective receptor-mediated impairment of growth factor activity in neonatal- and X-linked adrenoleukodystrophy patients.

Background Neonatal adrenoleukodystrophy (n-ALD) and X-linked ALD (X-ALD) patients present with demyelination, poor growth and progressive mental retardation. Growth factors are known to play a vital role in the development of children. Objective To examine the mitogenic activity of various growth factors in skin fibroblasts from n-ALD and X-ALD patients. Methods Skin fibroblast cultures from n-ALD and X-ALD patients, and controls were treated with 50 ng/mL of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) or insulin-like growth factor-1 (IGF-1) to examine DNA synthesis by 5-bromo-2'-deoxyuridine (BrdU) incorporation. Expression of receptors for PDGF, bFGF and IGF-1 was measured by western blotting. Serum levels of IGF-1 were assayed by enzyme-linked immunosorbent assay (ELISA). Results Fibroblasts from n-ALD and X-ALD patients had significantly (p < 0.01) less BrdU incorporation in response to fetal bovine serum (FBS). The mitogenic effect of PDGF, bFGF and IGF-1 was significantly lower in n-ALD as compared to control and X-ALD cells. X-ALD cells showed significant impairment in IGF-1-induced DNA synthesis. Expression of the FGF receptor (FGF-R) was significantly reduced in n-ALD cells. PDGF receptor remained unaffected, and IGF-1 receptor (IGF-1R) expression and serum IGF-1 levels were significantly (p < 0.01) reduced in n-ALD and X-ALD patients as compared to controls. Conclusions Growth factor activity differs in n-ALD and X-ALD patients, with marked impairment of IGF-1 function through receptor down-regulation.

Anaesthesia for a child with adrenoleukodystrophy: A case report and review of the literature

We present a 9-year-old boy with X-linked cerebral adrenoleukodystrophy (X-linked ALD) and previous umbilical cord transplant who required general anaesthesia. An anaesthetic plan for each individual should be tailored to ensure the best possible anaesthetic care for these patients. The anaesthetic considerations include mental retardation, seizure disorder, hypotonia, liver function abnormalities, gastro-oesophageal reflux, impaired adrenocortical function and immunosuppression. Pre-operative sedation should be avoided because of hypotonia of the pharyngeal muscles. Anti-convulsants are continued, and potentially epileptogenic anaesthetic agents are avoided. The patient was intubated using a modified rapid sequence induction with a head up position of 30 degrees. Four other cases have been reported in literature. Nevertheless, there is still no established anaesthetic management for these patients, and total intravenous anaesthesia can be considered as a safe and alternative method of anaesthesia. To the best of our knowledge, this is the first reported use of total intravenous anaesthesia with propofol and remifentanil in a case of cerebral adrenoleukodystrophy, and with a favourable outcome.

ABCD1 mutations and phenotype distribution in Chinese patients with X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder resulting from mutations within the ABCD1 gene. Adrenomyeloneuropathy (AMN) and childhood cerebral ALD (CCALD) are most common phenotypes in the Western ALD patients. Here we performed mutation analysis of ABCD1 in 10 Chinese ALD families and identified 8 mutations, including one novel deletion (c.1477_1488+11del23) and 7 known mutations. Mutations c.1772G>A and c.1816T>C were first reported in the Chinese patients. Mutations c.1661G>A and c.1679C>T were demonstrated to be de novo mutations. The dinucleotide deletion 1415_16delAG, described as a mutational hotspot in different ethnic groups, was identified in two families. In addition, we performed a retrospective nation-wide mutation study of X-linked ALD in China based on a literature review. The retrospective study further confirmed the hypothesis that exon 6 is a potential mutation cluster region in the Asian populations. Furthermore, it suggested that CCALD is the most common phenotype in China.

Recurrent Anion Gap Acidosis: An Unusual Presentation of X-Linked Adrenoleukodystrophy in a Five-year-old Male

We are presenting a five-year-old male with recurrent anion gap acidosis. During his last admission, it was detected that he had elevated VLCFA and the evaluation discovered that he had X-linked Adrenooleukodystrophy. He had the Addisonian only phenotype without any clinical or radiographic CNS findings. We were unable to find any other reports of this presentation of ALD. If the work-up of recurrent anion gap acidosis does not uncover an etiology, X-linked ALD should be considered in the differential diagnosis.

Successful allogeneic unrelated bone marrow transplantation using reduced‐intensity conditioning for the treatment of X‐linked adrenoleukodystrophy in a one‐yr‐old boy

The childhood cerebral form of X-linked ALD is a demyelinating disorder of the central nervous system, which rapidly leads to total disability and death. Allogeneic stem cell transplantation benefits patients who show early evidence of the demyelination. We report here a one-yr-old boy with ALD who received HLA-matched unrelated BMT in an early stage of the disease after careful planning and observation since his birth. BMT was performed when MRI began to show slight signal intensity changes in the white matter of the brain. Pretransplant conditioning consisted of fludarabine, l-PAM and TBI (2 Gy). GVHD prophylaxis consisted of cyclosporine A and short-course methotrexate. The patient showed an uneventful BMT course with fast and stable engraftment. Following BMT, the plasma levels of VLCFA decreased gradually and MRI changes improved. The patient did not have any evidence of further neurological deterioration 22 months following the transplant. Although this is still a short follow-up, it has been shown that BMT should be considered when a child has a biochemical diagnosis and MRI findings of ALD without any neurological signs. RIST should be considered as a pretransplant conditioning for ALD.

Simultaneous Determination of C22-C26 Very Long - Chain Fatty Acids Following tert-Butyldimethylsilyl Derivatization by Stable Isotope GC- MS for the Screening of Adrenoleucodystrophy

A rapid analytical method was developed to quantify very long-chain fatty acids (VLCFAs, C22:0, C24:0, C26:0) in human plasma with good sensitivity and specificity using tert-butyldimethylsilyl (TBDMS) derivatization and stable isotope GC-MS selective ion monitoring (GC-MS/SIM). Two-hundred and fifty <TEX>${\mu}L$</TEX> of plasma was fortified with deuterated stable isotope internal standards (d3-C22:0, d3-C24:0, d3-C26:0) and standard mixtures of chloroform and methanol, and then extracted with hexane and acetonitrile. To upper layer of liquid-liquid-extraction, N-(t-Butyldimethylsilyl)-N-methyltrifluoroacetamide was added and then heated to <TEX>$60^{\circ}C$</TEX> for 30 min to produce the TBDMS derivatives. Derivatives of VLCFAs were analyzed by GC-MS/SIM. Calibration curves showed a linear relationship for the target compounds in the concentration range of <TEX>$10^{-4}{\sim}2{\times}10^3\;{\mu}g/mL$</TEX> with the correlation coefficient ranging from 0.996 to 0.999. The limit of quantification for the plasma was <TEX>$10^{-4}{\sim}2{\times}10^{-4}\;{\mu}g/mL$</TEX> (S/N=3). When applied to the plasma specimens of patients with peroxisomal disorder, X-linked adrenoleucodystropy (ALD, Mckusick 202370), the method clearly differentiated normal subjects from ALD patients. The C24:0/C22:0 and C26:0/C22:0 ratios were significantly elevated in the plasma of patients with X-linked ALD compared to normal subjects. The new developed method might be useful for a rapid and sensitive diagnosis of X-linked ALD and other peroxisomal disorders.

Preimplantation genetic diagnosis of X-linked adrenoleukodystrophy (ALD) with gender determination using multiple displacement amplification

ALD is an X-linked recessive disorder which is secondary to a mutation in the ABCD1 gene (Xq28) and results neurological effects. The choice method for X-linked ALD-PGD is sexing. But fifty of female embryos are carriers and fifty percent of the discarded male embryos are unaffected diminishing the pool of embryos suitable for transfer. The aim of this work was to increase the reliability of PGD for X-linked ALD and to improve our ability to respond in a fast and safe way thanks to the availability of enough quality DNA obtained by MDA from a single cell for multiple PCR analyses. The MDA product was used for polymerase chain reaction (PCR) analysis of informative markers, used in the PGD–ALD program. A couple which wife carries a causative mutation 676 A > C in the ABCD1 gene that causes X-linked ALD. The affected wife was heterozygous at the DXS1073 and DXS9901 locus. To identify the sex chromosomes X22 informativity test were performed. MDA was used to amplify the whole-genome directly from a single cell. Segregation studies of the family were performed and showed that the ABCD1 extragenic and sex chromosome markers were informative. The development of a MDA–PGD protocol for ALD allowed for the diagnosis of five embryos. The amplification efficiency for DXS1073, DXS9901 and X22 was 12/15, 15/15 and 15/15, respectively. In addition, only ADO in DXS1073 was reported. Four embryos were determined to carry the non-affected haplotype, two embryos were affected, and one could not be diagnosed. Two healthy embryos were transferred 48 hours after culture, resulting in a singleton ongoing pregnancy and the birth of a healthy child. Sex selection for the PGD of X-linked ALD, using standard PCR procedures, has several disadvantages: (1) half of the male embryos could be healthy and will not be replaced, (2) the replacement of carrier female embryos cannot be avoided. This, has led to the fact that, the couples who wish to undergo PGD will rather decide on a specific DNA diagnosis rather than a simple sexing. The availability of enough DNA, thanks to the MDA reaction, allows different target amplification avoiding multiplex optimization protocol, resulting in a very accurate diagnosis. MDA would become a universal first step in PGD. The method we report for the diagnosis of X-linked ALD should be applicable to most patients carrying ALD as long as they were informative for the markers.

Synthesis of mevalonate pathway lipids in fibroblasts from Zellweger and X-linked ALD patients.

Fibroblasts were cultured to determine the involvement of peroxisomes in cholesterol and dolichol synthesis. For this purpose, the behavior of cells from patients with Zellweger syndrome, with X-linked adrenoleukodystrophy, and from nondiseased control subjects was studied. Cells both after pretreatment with mevinolin and without pretreatment were incubated in a medium containing [3H]-mevalonate. In fibroblasts from patients with peroxisomal defects, the cholesterol content and mevalonate incorporation into cholesterol were decreased by 10-20% in comparison with control cells. Mevinolin pretreatment decreased the incorporation rate of [3H]-mevalonate into cholesterol but increased the labeling of ubiquinone and dolichol both in diseased and control cells. Squalene synthase activity was unchanged, whereas the activity of farnesyl-pyrophosphate synthase was increased in the diseased states. The results show that in patients with peroxisomal deficiency neither the amount nor the rate of synthesis of cholesterol and dolichol is reduced to any greater extent.

Anaesthetic management of an adult patient with X-linked adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is a rare genetic disorder. Findings include various central nervous system problems in addition to adrenal insufficiency. We present a case of an adult man with X-linked ALD undergoing surgery. A 40-yr-old man with X-linked ALD presented with an intertrochanteric femoral fracture. Past medical history included recurrent lung atelectasis, urinary incontinence, mental retardation, seizure disorder, and adrenal insufficiency. No sedative pre-medications were ordered, but perioperative steroid coverage with 100 mg hydrocortisone was initiated. In the operating room, the patient would not allow placement of all monitors. Therefore, 1 mg midazolam then 275 mg thiopentone followed immediately by 40 mg rocuronium were used to induce anesthesia with the application of cricoid pressure and the remaining monitors. Fentanyl 50 micrograms i.v. was given soon after induction, and anaesthesia was maintained with nitrous oxide and isoflurane. No further muscle relaxant or opioid was administered and anaesthesia was uneventful. The trachea was extubated with the patient awake and he was taken to the recovery area in stable condition. Patients with X-linked ALD are rarely seen in a clinical setting because the condition is so uncommon. Adrenal insufficiency, mental retardation, and osteoporosis are major considerations for these patients. In addition, these patients are at risk for reflux, seizures, and major post-operative complications.

PRENATAL DIAGNOSIS OF PEROXISOMAL DISORDERS. † 869

Peroxisomal disorders are genetic disease caused either by a defect in peroxisome biogenesis resulting in deficiencies of multiple peroxisomal enzymes or by a deficiency of one peroxisomal enzyme. Seventeen different peroxisomal disorders are recognized nowadays, with progressive neurological deficits and early death in most. Both in peroxisome deficiency disorders(PDD) like Zellweger syndrome, neonatal Adrenoleukodystrophy (n-ALD) and infantile Refsum disease, in classic rhizomelic Chondrodysplasia punctata(RCDP) and disorders with a defect in peroxisomal beta-oxidation of fatty acids (including X-linked ALD) no effective treatment is available and early prenatal detection indicated. For PDD this is done by us by in vitro measurement of acylCoA:dihydroxyacetonephosphate acyltransferase(DHAPAT) activity and immuno(western)blotting with antisera raised against catalase, acylCoA oxidase and peroxisomal thiolase(Thio) resp. in uncultured chorionic villi(CV) homogenates. Since 1992 seventeen affected PDS fetusses were recognized by us by this procedure in sixty one at risk pregnancies in the 10th or 11th gestational week. Moreover, an additional thirteen affected PDS fetusses were found by analyzing de novo plasmalogen biosynthesis and very longchain fatty acids(VLCFA) in cultured CV-fibroblasts or amniocytes. Seven RCDP fetusses were diagnosed by the finding of abnormal immunoblots with anti-thiolase (absence of 41kDa band for mature thiolase protein) and deficient plasmalogens in CV. We also diagnosed isolated DHAPAT deficiency in a fetus by finding a deficiency of plasmalogens and DHAPAT, but normal Thio-blot in CV. Fifteen fetusses with a deficiency of one of the enzymes of peroxisomal beta-oxidation, including X-linked ALD, were diagnosed prenatally in 41 at risk pregnancies by the finding of elevated VLCFA and deficient activity of peroxisomal beta-oxidation in cultured CV-fibroblasts or amniocytes. No false positive or negative cases were found with these procedures.

X-LINKED ADRENOLEUKODYSTROPHY (ALD): HORMONAL AND CLINICAL FINDINGS DURING DIETARY ERUCIC-TRIOLEATE THERAPY

X-linked ALD is characterized by primary adrenal insufficiency, demyelination and accumulation of very long chain fatty acids (VLCFA). VLCFA have a toxic effect on adrenocortical cell by increasing cell membrane microviccosity, leading to decreased ability to respond to ACTH (Whitcomb RW et al. J Clin invest 81:185·188, 1988). The regimen of VLCFA restricted diet supplemented with a mixture of oleic and erucic acid (GTEO) determined, for the first time, a normalisation of plasma VLCFA levels in ALD patients. Thus the data suggest that the pathological changes affecting the nervous and endocrine system may be delayed, or even arrested, in these patients. We now report the effects on the clinical course of ALD of this therapeutic approach in 18 patients treated with dietary-GTOE supplementation up to 5 years. There was no effect on the clinical course in patients with childhood and adolescent ALD assessed by neurological, neuropsycological, and neuroadiological (NMI) evaluations. Patients with adrenomyeloneropathy and presymptomic did not exhibit progression of the disease. All but 3 patients had hyposdrenalism. Plasma eldosterone levels were reduced and PRA was increased. Interestingly, normalisation of VLCFA levels in these patients resulted in an increase of aldosterone (M±SD: 112.3±94.6 vs 379.2±12.1 pg/ml, p<0.05) and a reduction of PRA levels form 10.2±7.6 to 5.1±2.8 ng/ml/h, confirming that VLCFA excess has a direct toxic effect on the adrenals whereas other factors are more likely involved in the determination of the pathological changes in the nervous system.

Peroxisomal diseases.

The peroxisomal diseases, which are rare inborn metabolic errors, often have serious effects on the well being of the individual and many of them are fatal at an early age. The Zellweger cerebro-hepato-renal syndrome represents a group consisting of diseases with a generalized loss of peroxisomal functions and is considered as a prototype for peroxisomal dysfunction. The largest group includes those diseases where only a single peroxisomal function is impaired. The most common peroxisomal disease, x-linked adrenoleukodystrophy (ADL), belongs to this group, and neurological symptoms dominate among the patients. The primary diagnosis is usually based on clinical findings and measurement of accumulated or depleted metabolites in the body (e.g. very long chain fatty acids, bile acid intermediates or plasmalogens). Some progress has been made in treating of the peroxisomal diseases. Many patients with x-linked ALD have benefitted from the supplementation of the diet with long chain monounsaturated fatty acids like erucic acid or oleic acid with the simultaneous restriction of very long chain fatty acids. Docosahexenoate (C22:1) has also shown promising results in some studies.

Adult adrenoleukodystrophy: A sporadic case?

This is a report of a case of the adult cerebral form of X-linked ALD. The 27-year-old patient presented with psychiatric disturbances. NMR was performed and compared to CT scan to define cerebral demyelination. The level of hexacosanoate was found to be increased in the patient's serum. Biochemical analysis of the patient's mother's serum and cultured fibroblasts and of serum samples from 10 other members of the family who could have been carriers of this X-linked disease, produced negative results. Hence, it is most likely that this case has occurred sporadically. HLA determination revealed the DR2 antigen which is often associated with multiple sclerosis.

Lignoceroyl-CoASH ligase: enzyme defect in fatty acid β-oxidation system in X-linked childhood adrenoleukodystrophy

We have previously reported that the peroxisomal β-oxidation system for very long chain fatty acids is defective in X-linked childhood adrenoleukodystrophy [(1984) Proc. Natl. Acad. Sci. USA 81, 4203-4207]. In order to elucidate the specific enzyme defect, we examined the oxidation of [1- 14C]lignoceric acid, [1- 14C]lignoceroyl-CoA and (1- 14C)-labelled α,β-unsaturated lignoceroyl-CoA (substrates for the 1st, 2nd, and 3rd steps of the β-oxidation cycle, respectively). These studies suggest that the pathognomonic accumulation of very long chain fatty acids in X-linked childhood ALD may be due to the defective activity of peroxisomal very long chain (lignoceroyl-CoA) acyl-CoA ligase.

Hyperpipecolic acidemia in neonatal adrenoleukodystrophy.

Serum pipecolic acid was measured in patients with neonatal adrenoleukodystrophy (NALD), sex-linked ALD, and the cerebrohepatorenal syndrome of Zellweger. Pipecolic acid was elevated, often markedly, in most of the patients with NALD but in none of those with X-linked ALD or adrenomyeloneuropathy, or in normal adults and children, or children with cirrhosis or other neurodegenerative disorders. The demonstration of elevated serum pipecolic acid in NALD adds to the previously recognized elevation of very-long-chain fatty acids (another Zellweger syndrome sign) and suggests that generalized peroxisomal dysfunction may be a characteristic of NALD as it appears to be of Zellweger syndrome, which diseases share some clinical characteristics. The nosologic significance of these findings is discussed.