Epidemiology of X-linked adrenoleukodystrophy in Japan

To clarify the epidemiology of X-linked adrenoleukodystrophy (ALD) in Japan, we performed a questionnaire survey. Two hundred eighty-six patients, including 154 from internal medicine, 100 from pediatrics, 21 from psychiatry, and 11 from other hospitals, were reported to have ALD between 1990 and 1999. The data on 154 patients revealed the phenotypic distribution to be as follows: childhood cerebral form (29.9%), adrenomyeloneuropathy (25.3%), adult cerebral form (21.4%), adolescent form (9.1%), olivo-ponto-cerebellar form (8.4%), presymptomatic form (4.5%), and symptomatic female patient (1.3%). The adult cerebral form and olivo-ponto-cerebellar form were more common in Japan than in North America and Europe. The incidence of X-linked ALD in Japan was estimated to be between 1 : 30 000 and 1 : 50 000 boys, similar to previous reports. About half of the patients with adrenomyeloneuropathy and the olivo-ponto-cerebellar phenotype developed cerebral involvement with a mean interval of 8.2 and 2.2 years after ALD onset, respectively. The family histories revealed that brothers and first cousins tended to show similar phenotypes, whereas nephews tended to develop symptoms earlier than uncles. These data will help in understanding the natural history of X-linked ALD. Received: June 14, 2002 / Accepted: July 31, 2002 Acknowledgments This study was supported by a Research Grant on Specific Diseases from the Ministry of Health, Labour and Welfare of Japan. Correspondence to:Y. Takemoto     

X-连锁肾上腺脑白质营养不良产前诊断探讨

目的探讨X-连锁肾上腺脑白质营养不良(adrenoleukodystrophy,ALD)产前诊断的方法。方法应用气相色谱-质谱联用法对17例ALD高危孕妇进行了18次羊水细胞中极长链脂肪酸(very long chain fatty acids,VLCFAs)水平测定,其中8例胎儿出生后或引产后进行了血浆VLCFAs水平检测。应用PCR和测序方法对8例胎儿羊水细胞或生后外周血细胞DNA进行了基因突变分析(其中4例羊水细胞VLCFAs水平增高,4例VLCFAs正常)。应用Western杂交对同一家系的两例胎儿羊水细胞进行了ALD蛋白(ALD protein,ALDP)的检测(两例胎儿VLCFAs均增高,1例女性,1例男性)。结果18例胎儿中,11例羊水细胞VLCFAs水平正常,7例增高(3例男性,4例女性)。8例胎儿出生后或引产后血浆VLCFAs水平检测,3例增高,5例正常,与产前诊断结果相一致。其中4例羊水细胞VLCFAs水平增高的胎儿,均有ABCD1基因突变,4例羊水细胞VLCFAs水平正常者,均未发现突变。VLCFAs增高的男性胎儿,未检测到ALDP,VLCFAs增高的女性胎儿,可检测到ALDP。结论羊水细胞中VLCFAs水平检测可以准确地进行X-ALD产前诊断,结合基因突变分析及ALDP的测定,可进一步保证产前诊断的准确性。     

X-linked adrenoleukodystrophy: The Australasian experience

Our objective was to review the Australasian experience of X-linked adrenoleukodystrophy (ALD), to compare the spectrum of disease seen in Australasia with previously published data from elsewhere, and to assess the reliability of carrier testing. Study design was a retrospective review of records collected over a 15-year period, the setting was an international referral laboratory for the study of metabolic disease, and the subjects were all known cases of ALD diagnosed in Australia and New Zealand between 1981 and 1996 and their families. We estimate that the combined incidence of ALD and its variants in Australasia is at least 1.6 per 100,000. Of 95 affected males, 51 had cerebral adrenoleukodystrophy, 24 had adrenomyeloneuropathy, 15 had Addison's disease only, and 5 remained asymptomatic when last examined. However, the distribution of phenotypes among newly diagnosed patients has changed substantially over the last 15 years, with cerebral forms of the disease forming a decreasing proportion of new diagnoses. The measurement of plasma very long chain fatty acids (VLCFAs) alone detects 93% of women who can be proven to be carriers. The addition of genetic linkage studies or assay of VLCFAs in cultured fibroblasts improved this detection rate to the point that there were no obligate carriers who could not be detected using a combination of two or more techniques. Am. J. Med. Genet. 76:420–423, 1998. © 1998 Wiley-Liss, Inc.     

Mutational analysis of patients with X-linked adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is an X-linked neurodegenerative disorder characterized by elevated very long chain fatty acid (VLCFA) levels, reduced activity of peroxisomal VLCFA-CoA ligase, and variable phenotypic expression. A putative gene for ALD was recently identified and surprisingly encodes a protein (ALDP) that belongs to a family of transmembrane transporters regulated or activated by ATP (the ABC proteins). We have examined genomic DNA from ALD probands for mutations in the putative ALD gene. We detected large deletions of the carboxyl-terminal portion of the gene in 4 of 112 probands. Twenty-five of the ALD probands whose ALD genes appeared normal by Southern blot analysis were surveyed for mutations by Single Strand Conformation Polymorphism (SSCP) procedures and DNA sequence analysis. SSCP variants were detected in 22 probands and none in 60 X-chromosomes from normal individuals. Mutations were detected in all of the ALD probands. The mutations were distributed throughout the gene and did not corrate with phenotype. Approximately half were non-recurrent missense mutations of which 64% occurred in CpG dinucleotides. There was a cluster of frameshift mutations in a small region of exon 5, including an identical AG deletion in 7 unrelated probands. These data strongly support the supposition that mutations in the putative ALD gene result in ALD. © 1995 Wiley-Liss, Inc.     

X-连锁的肾上腺脑白质营养不良患者ABCD1基因突变分析

目的　分析我国 X-连锁的肾上腺脑白质营养不良 (X- linked adrenoleukodystrophy,X- AL D)患者 ABCD1基因突变。方法　提取 2 5例 AL D患者外周血基因组 DNA,用 PCR扩增和 DNA直接测序的方法 ,分析 AL D患者 ABCD1基因突变。结果　 2 5例患者中发现 18例有 17种不同的 ABCD1基因突变 ,突变存在于除 4、9和 10以外的每一个外显子 ,错义突变为最常见的类型。10例患者有 10种不同的错义突变 ,其中4种错义突变是国际首次报道 ;3例患者有 3种不同的无义突变 ;1例患者有碱基缺失导致移码突变 ;1例患者有剪切部位的碱基缺失 ;2例患者同时具有两个相同的同义突变。结论　我国 AL D患者大部分存在ABCD1基因突变 ,无突变热点。不同个体常有不同的突变点 ,检测到的突变率约为 70 %。突变类型和表型之间无特殊的相关关系。     

X-linked adrenoleukodystrophy: diagnostic and follow-up system in Japan

X-linked adrenoleukodystrophy (ALD) is an intractable neurodegenerative disease associated with the accumulation of very long-chain saturated fatty acids (VLCFA) in tissues and body fluids. We have established a Japanese referral center for the diagnosis of ALD, using VLCFA measurements and mutation analysis of the ABCD1 gene, and have identified 60 kinds of mutations in 69 Japanese ALD families, which included 38 missense mutations, 6 nonsense mutations, 8 frame-shift mutations, 3 amino acid deletions, 2 exon-skip mutations and 3 large deletions. A total of 24 kinds of mutations (40%) were identified only in Japanese patients by referring to the current worldwide ALD mutation database. There was no clear correlation between these mutations and phenotypes of 81 male patients in these 69 families. About 12% of the individuals with ALD had de novo mutations by mutation analysis in the male probands and their mothers, which should be helpful data for genetic counseling. The only effective therapy for the cerebral form of ALD should be hematopoietic stem cell transplantation at the early stages of the cerebral symptoms, therefore, we performed presymptomatic diagnosis of ALD by extended familial screening of the probands with careful genetic counseling, and established a long follow-up system for these patients to prevent the progression of brain involvement and to monitor the adrenocortical insufficiency. Further elucidation of pathology in ALD, especially concerning the mechanisms of the onset of brain involvement, is expected.     

Accurate DNA-based diagnostic and carrier testing for X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy is a serious and often fatal disorder, affecting the white matter of the nervous system, the adrenal cortex, and the testis. The gene mutated in X-ALD encodes a peroxisomal membrane protein, ALDP. The presence of very long chain fatty acids in plasma is highly diagnostic for affected males and carrier females, but exclusion of carrier status biochemically is unreliable. Molecular analysis of the X-ALD gene has the potential to either identify or rule out carrier status accurately, but is complicated by the existence of autosomal paralogs. We have developed and validated a robust DNA diagnostic test for this disorder involving nonnested genomic amplification of the X-ALD gene, followed by fluorescent dye-primer sequencing and analysis. This protocol provides a highly reliable means of determining carrier status in women at risk for transmitting X-ALD and is applicable to a clinical diagnostic laboratory.     

X-linked adrenoleukodystrophy: role of very long-chain acyl-CoA synthetases

The principal biochemical abnormality in the neurodegenerative disorder X-linked adrenoleukodystrophy (X-ALD) is elevated plasma and tissue levels of very long-chain fatty acids (VLCFA). Enzymes with very long-chain acyl-CoA synthetase (VLACS) activity are required for VLCFA metabolism, including degradation by peroxisomal beta-oxidation or incorporation into complex lipids, and may also participate in VLCFA synthesis. Two enzymes with VLACS activity, ACSVL1 and BG1, were investigated for their potential role in X-ALD biochemical pathology. Skin fibroblast mRNA levels for ACSVL1, an enzyme previously shown to be in peroxisomes and to participate in VLCFA beta-oxidation, were not significantly different between normal controls, patients with childhood cerebral X-ALD, and patients with adrenomyeloneuropathy. Similar results were obtained with mRNA for BG1, a non-peroxisomal enzyme that is highly expressed in nervous system, adrenal gland, and testis, the principal tissues pathologically affected in X-ALD. No significant differences in the immunohistochemical staining patterns of tissues expressing either ACSVL1 or BG1 were observed when wild-type and X-ALD mice were compared. Western blot analysis of BG1 protein levels showed no differences between fibroblasts from controls, cerebral X-ALD, or adrenomyeloneuropathy patients. BG1 protein levels were similar in wild-type and X-ALD mouse brain, spinal cord, testis, and adrenal gland. We hypothesized that one function of BG1 was to direct VLCFA into the cholesterol ester synthesis pathway. However, BG1 depletion in Neuro2a cells using RNA interference did not decrease incorporation of labeled VLCFA into cholesterol esters. We conclude that the role, if any, of ACSVL1 and BG1 in X-ALD biochemical pathology is indirect.     

Elongation of very long-chain fatty acids is enhanced in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a progressive neurodegenerative disorder characterized by the accumulation of saturated and mono-unsaturated very long-chain fatty acids (VLCFA) and reduced peroxisomal VLCFA beta-oxidation activity. In this study, we investigated the role of VLCFA biosynthesis in X-ALD fibroblasts. Our data demonstrate that elongation of both saturated and mono-unsaturated VLCFAs is enhanced in fibroblasts from patients with peroxisomal beta-oxidation defects including X-ALD, and peroxisome biogenesis disorders. These data indicate that enhanced VLCFA elongation is a general phenomenon associated with an impairment in peroxisomal beta-oxidation, and not specific for X-ALD alone. Analysis of plasma samples from patients with X-ALD and different peroxisomal beta-oxidation deficiencies revealed increased concentrations of VLCFAs up to 32 carbons. We infer that enhanced elongation does not result from impaired peroxisomal beta-oxidation alone, but is due to the additional effect of unchecked chain elongation. We demonstrate that elongated VLCFAs are incorporated into complex lipids. The role of chain elongation was also studied retrospectively in samples from patients with X-ALD previously treated with "Lorenzo's oil." We found that the decrease in plasma C26:0 previously found is offset by the increase of mono-unsaturated VLCFAs, not measured previously during the trial. We conclude that evaluation of treatment protocols for disorders of peroxisomal beta-oxidation making use of plasma samples should include the measurement of saturated and unsaturated VLCFAs of chain lengths above 26 carbon atoms. We also conclude that chain elongation offers an interesting target to be studied as a possible mode of treatment for X-ALD and other peroxisomal beta-oxidation disorders.     

蛋氨酸代谢中3个相关基因的多态性与X-连锁肾上腺脑白质营养不良表型的关系

目的 探讨蛋氨酸代谢中3个相关基因的多态性与X-连锁肾上腺脑白质营养不良(X-linked adrenoleukodystrophy,X-ALD)患者临床表型、疾病严重程度的关系.方法 对120例X-ALD患者的临床资料进行分析,应用聚合酶链反应和产物直接测序法对蛋氨酸代谢途径中3个关键酶的基因多态性进行分析,包括转钴胺素2(transcobalamin 2,TC2)c.776C/G、5-甲基四氢叶酸-同型半胱氨酸-S-甲基转移酶(5-methyltetrahydrofolate-homocysteine-S-methyltransferase,MTR)c.2756A/G与胱硫醚β-合成酶(cystathionine beta-synthase,CBS)c.844ins68,分析其多态性与X-ALD患者表型、病情严重程度的关系.结果 TC2 c.776C/G的GG基因型频率在中枢神经系统受累者中(39%)高于正常对照组(27%),差异具有统计学意义(P=0.012),其它两个多态性未发现有统计学差异;与脑型患者疾病严重程度无相关性.结论 X-ALD患者的 TC2 c.776C/G的基因型可能与X-ALD的表型有关.未发现CBS c.844ins68及MTR c.2756A/G与X-ALD的表型有相关性.

Abstract：

Objective To investigate the association of the polymorphisms of methionine metabolism genes and the phenotype of X-linked adrenoleukodystrophy (X-ALD) and clinical severity. Methods The clinical information of 120 X-ALD patients were analyzed and three genetic variants involved in the methionine metabolism, including cystathionine beta-synthase (CBS) c.844_855ins68, 5-methyltetrahydrofolate-homocysteine-S-methyltransferase (MTR) c.2756A/G, and transcobalamin 2 (TC2) c.776C/G were analyzed by polymerase chain reaction and sequencing. The association between these polymorphisms and phenotype of X-ALD was studied. Results The frequency of GG genotype of the TC2 c.776C/G was higher in patients with central nervous system(CNS) demyelination than in controls (P=0.012). However, the other two polymorphisms did not show any significant associations with the phenotypes. Conclusion The GG genotype of TC2 c.776C/G may contribute to X-ALD phenotype.     

Thrombocytopenia induced by erucic acid therapy in patients with X-linked adrenoleukodystrophy

Summary Five patients with various clinical and genetic phenotypes of adrenoleukodystrophy were treated with a diet enriched with glycerol trioleate and glycerol trierucate (GTE). In all patients platelet counts decreased upon the administration of GTE, but no bleeding symptoms occurred in any of the patients, and bleeding time remained normal. Pseudothrombocytopenia was excluded in all patients. Thrombocytopenia was marked (84000–37000/mm) in three of the patients but was fully reversible after discontinuation of GTE. Mean platelet volumes were abnormally increased in all patients. When GTE was again administered by stepwise increasing the daily dose, platelet counts showed a clearly dose-dependent decrease. Bone marrow biopsies revealed no evidence of reduced megakaryocytopoiesis. The data indicate that in patients with adrenoleukodystrophy treated with GTE platelet counts should be closely monitored because thrombocytopenia may limit the maximal daily intake of GTE.Abbreviations ALD adrenoleukodystrophy - AMN adrenomyeloneuropathy - VLCFA very long chain fatty acids (C22C26) - GTO glycerol trioleate (C18:1) - GTE glycerol trierucate (C22:1)     

Evaluation of pharmacological induction of fatty acid beta-oxidation in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurometabolic disorder associated with elevated levels of saturated unbranched very-long-chain fatty acids (VLCFA; C > 22:0) in plasma and tissues, and reduced VLCFA beta-oxidation in fibroblasts, white blood cells, and amniocytes from X-ALD patients. The X-ALD gene (ABCD1) at Xq28 encodes the adrenoleukodystrophy protein (ALDP) that is related to the peroxisomal ATP-binding cassette (ABCD) transmembrane half-transporter proteins. The function of ALDP is unknown and its role in VLCFA accumulation unresolved. Previously, our laboratory has shown that sodium 4-phenylbutyrate (4PBA) treatment of X-ALD fibroblasts results in increased peroxisomal VLCFA beta-oxidation activity and increased expression of the X-ALD-related protein, ALDRP, encoded by the ABCD2 gene. In this study, the effect of various pharmacological agents on VLCFA beta-oxidation in ALD mouse fibroblasts is tested. 4PBA, styrylacetate and benzyloxyacetate (structurally related to 4PBA), and trichostatin A (functionally related to 4PBA) increase both VLCFA (peroxisomal) and long-chain fatty acid [LCFA (peroxisomal and mitochondrial)] beta-oxidation. Isobutyrate, zaprinast, hydroxyurea, and 5-azacytidine had no effect on VLCFA or LCFA beta-oxidation. Lovastatin had no effect on fatty acid beta-oxidation under normal tissue culture conditions but did result in an increase in both VLCFA and LCFA beta-oxidation when ALD mouse fibroblasts were cultured in the absence of cholesterol. The effect of trichostatin A on peroxisomal VLCFA beta-oxidation is shown to be independent of an increase in ALDRP expression, suggesting that correction of the biochemical abnormality in X-ALD is not dependent on pharmacological induction of a redundant gene (ABCD2). These studies contribute to a better understanding of the role of ALDP in VLCFA accumulation and may lead to the development of more effective pharmacological therapies.     

X-linked adrenoleukodystrophy: ABCD1 de novo mutations and mosaicism

X-linked adrenoleukodystrophy (X-ALD) is a progressive peroxisomal disorder affecting adrenal glands, testes and myelin stability that is caused by mutations in the ABCD1 (NM_000033) gene. Males with X-ALD may be diagnosed by the demonstration of elevated very long chain fatty acid (VLCFA) levels in plasma. In contrast, only 80% of female carriers have elevated plasma VLCFA; therefore targeted mutation analysis is the most effective means for carrier detection. Amongst 489 X-ALD families tested at Kennedy Krieger Institute, we identified 20 cases in which the ABCD1 mutation was de novo in the index case, indicating that the mutation arose in the maternal germ line and supporting a new mutation rate of at least 4.1% for this group. In addition, we identified 10 cases in which a de novo mutation arose in the mother or the grandmother of the index case. In two of these cases studies indicated that the mothers were low level gonosomal mosaics. In a third case biochemical, molecular and pedigree analysis indicated the mother was a gonadal mosaic. To the best of our knowledge mosaicism has not been previously reported in X-ALD. In addition, we identified one pedigree in which the maternal grandfather was mosaic for the familial ABCD1 mutation. Less than 1% of our patient population had evidence of gonadal or gonosomal mosaicism, suggesting it is a rare occurrence for this gene and its associated disorders. However, the residual maternal risk for having additional ovum carrying the mutant allele identified in an index case that appears to have a de novo mutation is at least 13%.     

The effect of bone marrow transplantation on oxidative stress in X-linked adrenoleukodystrophy

Oxidative stress plays an important role in the pathophysiology of neurodegenerative diseases, including X-linked adrenoleukodystrophy (X-ALD). In the present work, we evaluated lipid (malondialdehyde [MDA] content) and protein (sulfhydryl and carbonyl contents) oxidative damage parameters in plasma from X-ALD patients before and after bone marrow transplant (BMT), in order to verify if this treatment is capable to alter the oxidative parameters studied. We also evaluated the plasma concentration of hexacosanoic acid (C26:0) from X-ALD patients and correlated it with the oxidative damage parameters investigated. We observed that MDA content was significantly increased in plasma of X-ALD patients before BMT and after BMT when compared to controls, and that it was significantly reduced in plasma of X-ALD after BMT when compared to the before BMT group. These results indicate that lipid peroxidation is stimulated in X-ALD patients but there is a significant reduction of lipid peroxidation after BMT. Next, we observed a significant reduction of sulfhydryl content in plasma of X-ALD patients before BMT compared to controls indicating protein oxidative damage and that this measurement was increased in these patients after BMT as compared to before BMT. We found no significant differences in plasma carbonyl content in X-ALD patients before and after BMT as compared to controls. However, we observed a significant reduction in this parameter in X-ALD patients after BMT compared to before BMT. Finally, C26:0 plasma concentration was significantly reduced in X-ALD patients after BMT when compared to before BMT. We found no significant correlations between MDA and carbonyl values with C26:0 levels of the patients before BMT and after BMT, but a significant inverse correlation between sulfhydryl content and C26:0 levels was detected. In conclusion, the present study reinforces the hypothesis that lipid peroxidation and protein damage are induced in plasma of X-ALD patients and, in addition, demonstrates that BMT treatment is capable to reduce this pathogenic process. Taken together, the data obtained from plasma of X-ALD patients before and after BMT showing induction and protection, respectively, of oxidative stress, allowed to suggest that BMT, when well succeeded and under the recommendations, is effective to reduce C26:0 plasma levels and the increased lipid and protein oxidative damage in X-ALD.     

X-linked adrenoleukodystrophy: Phenotype distribution and expression of ALDP in Spanish kindreds

X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder caused by an impairment in peroxisomal β-oxidation of very long straight-chain fatty acids (VLCFAs). Six clinical phenotypes have been delineated: childhood cerebral (CCALD), adolescent cerebral (AdolCALD), adult cerebral (ACALD), adrenomyeloneuropathy (AMN), Addison-only (AO), and presymptomatic (PALD). The distribution of phenotypes varies in different countries. We have diagnosed biochemically 60 X-ALD Spanish patients belonging to 48 kindreds. Their phenotypic distribution was: CCALD plus AdolCALD, 33%; ACALD, 16%; AMN, 27%; AO, 12%; and PALD, 12%. These results contrast with the distribution described in other countries, due to a higher prevalence of the ACALD form. Regarding the expression of the protein product (ALDP), we studied 17 kindreds using immunochemical techniques and found absence of ALDP in 84% of cases. We also studied 13 females from 7 negative ALDP kindreds in order to correlate ALDP expression and the carrier status established by VLCFA measurement. In one case with normal VLCFA levels in serum and fibroblasts, we observed mosaicism in ALDP expression. This fact supports the use of this technique for identifying carriers. Am. J. Med. Genet. 76:424–427, 1998. © 1998 Wiley-Liss, Inc.     

Co-expression of mutated and normal adrenoleukodystrophy protein reduces protein function: implications for gene therapy of X-linked adrenoleukodystrophy

Inherited defects in the X-chromosomal adrenoleukodystrophy (ALD; ABCD1) gene are the genetic cause of the severe neurodegenerative disorder X-linked adrenoleukodystrophy (X-ALD). Biochemically the accumulation of very long-chain fatty acids, caused by impaired peroxisomal beta-oxidation, is the pathognomonic characteristic of the disease. Due to the X-chromosomal inheritance of X-ALD no data are available to clarify the question whether mutated adrenoleukodystrophy proteins (ALDPs) can negatively influence normal ALDP function. Here we show that restoration of beta-oxidation in X-ALD fibroblasts following transient transfection with normal ALD cDNA is more effective in ALDP-deficient fibroblasts compared with fibroblasts expressing normal amounts of mutated ALDP. Furthermore, we utilized the HeLa Tet-on system to construct a stable HeLa cell line expressing a constant level of endogenous ALDP and doxycycline-inducible levels of mutated ALDP. The induction was doxycycline dosage-dependent and the ALDP correctly localized. Interestingly, although mutated ALDP increased >6-fold in a dosage-dependent manner the total amount of ALDP (mutated and normal) remained approximately even as demonstrated by western blot and flow cytometric analyses. Thus, apparently mutated and normal ALDP compete for integration into a limited number of sites in the peroxisomal membrane. Consequently, increased amounts of mutated ALDP resulted in decreased peroxisomal beta-oxidation and accumulation of very long-chain fatty acids. These findings have direct implications on future gene therapy approaches for treatment of X-ALD, since in some patients a non-functional endogenous protein could act in a dominant negative way or displace the introduced, normal protein.     

Outcomes of unrelated umbilical cord blood transplantation for X-linked adrenoleukodystrophy.

Adrenoleukodystrophy (ALD) is an X-linked disorder caused by a defect in the metabolism of long chain fatty acids leading to demyelination, neurodegeneration, and death. The disease typically presents in young boys and adolescent boys. Allogeneic bone marrow transplantation has been used to halt progression of the disease. However, many patients lack suitable HLA- matched related donors and must rely on unmatched donors for a source of stem cells. The purpose of this study was to evaluate outcomes of unrelated donor umbilical cord blood transplantation after chemotherapy-based myeloablative conditioning and retrospectively determine if baseline studies correlate and help predict outcome. Between November 22, 1996, and November 3, 2005, 12 boys with X-linked ALD who lacked HL- matched related donors were referred to Duke University Medical Center for transplantation. These children were conditioned with myeloablative therapy including busulfan, cyclophosphamide, and antithymocyte globulin before receiving umbilical cord-blood transplants from unrelated donors. Baseline studies of neurophysiologic, neuroimaging, and neurodevelopmental status were performed and patients were subsequently evaluated for survival, engraftment, graft-versus-host disease, and neurodevelopmental outcomes. A substudy evaluated whether baseline neuroimaging and neurophysiologic studies correlated with cognitive and motor function and if these studies were predictive of posttransplantation outcomes. The umbilical cord blood grafts had normal levels of very long chain fatty acids. They delivered a median of 6.98 x 10(7) nucleated cells per kilogram of recipient body weight and were discordant for up to 4 of 6 HLA markers. Neutrophil engraftment occurred at a median of 22.9 days after transplantation. Three patients had grade II-IV acute graft-versus-host disease; 2 had extensive chronic graft-versus-host disease. Cumulative incidence of overall survival of the group at 6 months is 66.7% (95% confidence interval 39.9-93.3%). Median follow-up was 3.3 years (range 12 days to 6.3 years). As previously reported with bone marrow transplantation, symptomatic patients faired poorly with lower survival and rapid deterioration of neurologic function. This study included 3 patients transplanted at a very young age (2.6-3.5 years) before the onset of clinical symptoms who continue to develop at a normal rate for 3-5 years posttransplant. Although baseline Loes scores correlated with cognitive and motor outcome, neurophysiologic studies failed to show statistically significant differences. Transplantation of boys with X-linked ALD using partial HLA-matched umbilical cord blood yields similar results to those previously reported after bone marrow transplantation. Superior outcomes were seen in neurologically asymptomatic boys less than 3.5 years of age at the time of transplantation. Baseline Loes scores were a strong predictor of cognitive and motor outcome.     

Evaluation of the therapeutic potential of PPARalpha agonists for X-linked adrenoleukodystrophy

Adrenoleukodystrophy protein (ABCD1), a peroxisomal membrane protein, is mutated in patients affected by X-linked adrenoleukodystrophy (X-ALD). Adrenoleukodystrophy-related protein (ABCD2) is the closest relative of ABCD1. Pharmacological induction of ABCD2 gene expression has been proposed as a novel therapy strategy for X-ALD. Fibrates induce peroxisome proliferation and Abcd2 expression in rodent liver. Here we evaluate the possibility of using peroxisome proliferator-activated receptor alpha (PPARalpha) agonists for pharmacological induction of ABCD2 expression. In the liver of PPARalpha-deficient mice, both the constitutive and the fenofibrate-inducible Abcd2 gene expression was found to be PPARalpha-dependent. In the brain, PPARalpha-deficiency has no effect on Abcd2 expression. In mice orally treated with the novel, highly selective, and potent PPARalpha agonists GW 7647, GW 6867, and tetradecylthioacetic acid, Abcd2 expression was induced in liver and adrenal glands, but not in brain and testis. None of four putative PPREs identified in the 5(')-flanking DNA and in intron 1 of the Abcd2 gene conferred fibrate response in luciferase reporter assays. Thus, although fibrate-mediated Abcd2 induction is PPARalpha-dependent, it appears to be an indirect mechanism. Within the mouse Abcd2 promoter, a putative sterol regulatory element (SRE) similar in sequence and position to the characterized SRE sequence of the human ABCD2 promoter, was identified. A PPARalpha dependent induction of the sterol regulatory-binding protein 2 (SREBP2) and a down-regulation of SREBP1c mRNA levels could be demonstrated after fenofibrate treatment of mice. Our results suggest that the PPARalpha agonist-mediated induction of Abcd2 expression seems to be indirect and possibly mediated by SREBP2.     

异基因造血干细胞移植治疗X-连锁肾上腺脑白质营养不良

背景：X-连锁肾上腺脑白质营养不良一直是国内外遗传界研究的热点,对此病的治疗一直缺乏有效的手段。 目的：分析2例异基因造血干细胞移植治疗X-连锁肾上腺脑白质营养不良的疗效和并发症。 方法：对华中科技大学同济医学院附属同济医院2例进行异基因造血干细胞移植的X-连锁肾上腺脑白质营养不良患儿进行综合分析及基因检测,观察移植成功情况及移植后并发症的发生。 结果与结论：2例均为儿童脑型X-连锁肾上腺脑白质营养不良。1例异基因造血干细胞移植成功,但发生严重的移植相关并发症,另1例移植失败。异基因造血干细胞移植是目前治疗早期儿童脑型X-连锁肾上腺脑白质营养不良的有效方法,但最终的疗效受移植是否成功及移植后并发症等因素的影响,且异基因造血干细胞移植的疗效尚需要长期的观察。