ABCD1 p.Arg591Gln
ClinVar: |
c.1771C>T
,
p.Arg591Trp
D
, Pathogenic
|
Predicted by SNAP2: | A: D (91%), C: D (95%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: D (95%), I: D (95%), K: D (91%), L: D (91%), M: D (91%), N: D (95%), P: D (95%), Q: D (95%), S: D (95%), T: D (95%), V: D (95%), W: D (95%), Y: D (95%), |
Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: N, L: D, M: D, N: D, P: D, Q: D, S: D, T: D, V: D, W: D, Y: D, |
[switch to compact view]
Comments [show]
None has been submitted yet.
[hide] ABCD1 mutations and the X-linked adrenoleukodystro... Hum Mutat. 2001 Dec;18(6):499-515. Kemp S, Pujol A, Waterham HR, van Geel BM, Boehm CD, Raymond GV, Cutting GR, Wanders RJ, Moser HW
ABCD1 mutations and the X-linked adrenoleukodystrophy mutation database: role in diagnosis and clinical correlations.
Hum Mutat. 2001 Dec;18(6):499-515., [PMID:11748843]
Abstract [show]
X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene, which encodes a peroxisomal ABC half-transporter (ALDP) involved in the import of very long-chain fatty acids (VLCFA) into the peroxisome. The disease is characterized by a striking and unpredictable variation in phenotypic expression. Phenotypes include the rapidly progressive childhood cerebral form (CCALD), the milder adult form, adrenomyeloneuropathy (AMN), and variants without neurologic involvement. There is no apparent correlation between genotype and phenotype. In males, unambiguous diagnosis can be achieved by demonstration of elevated levels of VLCFA in plasma. In 15 to 20% of obligate heterozygotes, however, test results are false-negative. Therefore, mutation analysis is the only reliable method for the identification of heterozygotes. Since most X-ALD kindreds have a unique mutation, a great number of mutations have been identified in the ABCD1 gene in the last seven years. In order to catalog and facilitate the analysis of these mutations, we have established a mutation database for X-ALD ( http://www.x-ald.nl). In this review we report a detailed analysis of all 406 X-ALD mutations currently included in the database. Also, we present 47 novel mutations. In addition, we review the various X-ALD phenotypes, the different diagnostic tools, and the need for extended family screening for the identification of new patients.
Comments [show]
None has been submitted yet.
No. Sentence Comment
259 For example, two disease-causing missense mutations, P484R and R591Q.
X
ABCD1 p.Arg591Gln 11748843:259:63
status: NEW[hide] Homo- and heterodimerization of peroxisomal ATP-bi... J Biol Chem. 1999 Nov 12;274(46):32738-43. Liu LX, Janvier K, Berteaux-Lecellier V, Cartier N, Benarous R, Aubourg P
Homo- and heterodimerization of peroxisomal ATP-binding cassette half-transporters.
J Biol Chem. 1999 Nov 12;274(46):32738-43., [PMID:10551832]
Abstract [show]
Mammalian peroxisomal proteins adrenoleukodystrophy protein (ALDP), adrenoleukodystrophy-related protein (ALDRP), and 70-kDa peroxisomal protein (PMP70) belong to the superfamily of ATP-binding cassette (ABC) transporters. Unlike many ABC transporters that are single functional proteins with two related halves, ALDP, ALDRP, and PMP70 have the structure of ABC half-transporters. The dysfunction of ALDP is responsible for X-linked adrenoleukodystrophy (X-ALD), a neurodegenerative disorder in which saturated very long-chain fatty acids accumulate because of their impaired peroxisomal beta-oxidation. No disease has so far been associated with mutations of adrenoleukodystrophy-related or PMP70 genes. It has been proposed that peroxisomal ABC transporters need to dimerize to exert import functions. Using the yeast two-hybrid system, we show that homo- as well as heterodimerization occur between the carboxyl-terminal halves of ALDP, ALDRP, and PMP70. Two X-ALD disease mutations located in the carboxyl-terminal half of ALDP affect both homo- and heterodimerization of ALDP. Co-immunoprecipitation demonstrated the homodimerization of ALDP, the heterodimerization of ALDP with PMP70 or ALDRP, and the heterodimerization of ALDRP with PMP70. These results provide the first evidence of both homo- and heterodimerization of mammalian ABC half-transporters and suggest that the loss of ALDP dimerization plays a role in X-ALD pathogenesis.
Comments [show]
None has been submitted yet.
No. Sentence Comment
47 ALD point mutations (R389H, R401Q, P484R, and R591Q) were individually introduced into pGBT- and pLEX-hALDPc by site-directed mutagenesis using "overlap extension PCR" with Pfu polymerase (Stratagene) and appropriate primers (25).
X
ABCD1 p.Arg591Gln 10551832:47:46
status: NEW72 These mutations (R389H, R401Q, P484R, and R591Q) were generated as described above and tested in two-hybrid assays.
X
ABCD1 p.Arg591Gln 10551832:72:42
status: NEW73 The P484R mutation leads to a decreased amount of ALDP in patient fibroblasts,3 whereas the three other mutations have no effect on ALDP stability in vivo (28-31).
X
ABCD1 p.Arg591Gln 10551832:73:27
status: NEW74 Our results show that the mutations R389H and R401Q had no effect on the interactions of hALDPc with itself (Fig. 2A, rows 1, 3, and 5), mALDRPc (Fig. 2B, rows 1, 3, and 5), or hPMP70c (Fig. 2C, rows 1, 3, and 5).
X
ABCD1 p.Arg591Gln 10551832:74:27
status: NEW75 In contrast, the P484R and R591Q mutations 2 L. X. Liu, K. Janvier, V. Berteaux-Lecellier, N. Cartier, R. Benarous, and P. Aubourg, unpublished results.
X
ABCD1 p.Arg591Gln 10551832:75:27
status: NEW90 B and C, interactions of wild type and mutated (R389H, R401Q, P484R, and R591Q) ALDPc with mALDRPc and hPMP70c.
X
ABCD1 p.Arg591Gln 10551832:90:73
status: NEW95 A, HF7c yeast strains expressing wild type or mutated (R389H, R401Q, P484R, and R591Q) ALDPc fused to Gal4-BD were analyzed for histidine auxotrophy (left panel, medium with histidine; right panel, medium without histidine).
X
ABCD1 p.Arg591Gln 10551832:95:80
status: NEW152 In contrast, the R591Q disease mutation, which alters the dimerization of ALDP in the yeast two-hybrid assays, does not lead to ALDP unstability in vivo.
X
ABCD1 p.Arg591Gln 10551832:152:17
status: NEW46 ALD point mutations (R389H, R401Q, P484R, and R591Q) were individually introduced into pGBT- and pLEX-hALDPc by site-directed mutagenesis using "overlap extension PCR" with Pfu polymerase (Stratagene) and appropriate primers (25).
X
ABCD1 p.Arg591Gln 10551832:46:46
status: NEW71 These mutations (R389H, R401Q, P484R, and R591Q) were generated as described above and tested in two-hybrid assays.
X
ABCD1 p.Arg591Gln 10551832:71:42
status: NEW89 B and C, interactions of wild type and mutated (R389H, R401Q, P484R, and R591Q) ALDPc with mALDRPc and hPMP70c.
X
ABCD1 p.Arg591Gln 10551832:89:73
status: NEW94 A, HF7c yeast strains expressing wild type or mutated (R389H, R401Q, P484R, and R591Q) ALDPc fused to Gal4-BD were analyzed for histidine auxotrophy (left panel, medium with histidine; right panel, medium without histidine).
X
ABCD1 p.Arg591Gln 10551832:94:80
status: NEW151 In contrast, the R591Q disease mutation, which alters the dimerization of ALDP in the yeast two-hybrid assays, does not lead to ALDP unstability in vivo.
X
ABCD1 p.Arg591Gln 10551832:151:17
status: NEW45 ALD point mutations (R389H, R401Q, P484R, and R591Q) were individually introduced into pGBT- and pLEX-hALDPc by site-directed mutagenesis using "overlap extension PCR" with Pfu polymerase (Stratagene) and appropriate primers (25).
X
ABCD1 p.Arg591Gln 10551832:45:46
status: NEW70 These mutations (R389H, R401Q, P484R, and R591Q) were generated as described above and tested in two-hybrid assays.
X
ABCD1 p.Arg591Gln 10551832:70:42
status: NEW88 B and C, interactions of wild type and mutated (R389H, R401Q, P484R, and R591Q) ALDPc with mALDRPc and hPMP70c.
X
ABCD1 p.Arg591Gln 10551832:88:73
status: NEW93 A, HF7c yeast strains expressing wild type or mutated (R389H, R401Q, P484R, and R591Q) ALDPc fused to Gal4-BD were analyzed for histidine auxotrophy (left panel, medium with histidine; right panel, medium without histidine).
X
ABCD1 p.Arg591Gln 10551832:93:80
status: NEW150 In contrast, the R591Q disease mutation, which alters the dimerization of ALDP in the yeast two-hybrid assays, does not lead to ALDP unstability in vivo.
X
ABCD1 p.Arg591Gln 10551832:150:17
status: NEW[hide] Two novel missense mutations in the ATP-binding do... Clin Genet. 1997 May;51(5):322-5. Imamura A, Suzuki Y, Song XQ, Fukao T, Uchiyama A, Shimozawa N, Kamijo K, Hashimoto T, Orii T, Kondo N
Two novel missense mutations in the ATP-binding domain of the adrenoleukodystrophy gene: immunoblotting and immunocytological study of two patients.
Clin Genet. 1997 May;51(5):322-5., [PMID:9212180]
Abstract [show]
Two novel missense mutations, 1939G to A (R518Q) and 2017A to G (Q544R) were identified in Japanese patients with adrenoleukodystrophy (ALD). They are located in exon 6, which encodes part of the putative adenosine triphosphate binding domain of ALD protein. The ALD protein carrying the R518Q mutation was undetectable in fibroblasts, by immunoblot and immunofluorescence analysis, while the Q544R mutation had no apparent effect on the stability and localization of the ALD protein, but is expected to affect its function.
Comments [show]
None has been submitted yet.
No. Sentence Comment
62 The immunofluorescence study has revealed positive immunoreactivity with anti-ALD protein antibody in a pathogenic ALD mutant, R591Q, between the Walker A and B motifs (Watkins et al. 1995),while ALD protein was not detectable in ALD protein mutants.
X
ABCD1 p.Arg591Gln 9212180:62:127
status: NEW[hide] X-linked adrenoleukodystrophy: clinical, biochemic... Biochim Biophys Acta. 2006 Dec;1763(12):1721-32. Epub 2006 Jul 26. Berger J, Gartner J
X-linked adrenoleukodystrophy: clinical, biochemical and pathogenetic aspects.
Biochim Biophys Acta. 2006 Dec;1763(12):1721-32. Epub 2006 Jul 26., [PMID:16949688]
Abstract [show]
X-linked adrenoleukodystrophy (X-ALD) is a clinically heterogeneous disorder ranging from the severe childhood cerebral form to asymptomatic persons. The overall incidence is 1:16,800 including hemizygotes as well as heterozygotes. The principal molecular defect is due to inborn mutations in the ABCD1 gene encoding the adrenoleukodystrophy protein (ALDP), a transporter in the peroxisome membrane. ALDP is involved in the transport of substrates from the cytoplasm into the peroxisomal lumen. ALDP defects lead to characteristic accumulation of saturated very long-chain fatty acids, the diagnostic disease marker. The pathogenesis is unclear. Different molecular mechanisms seem to induce inflammatory demyelination, neurodegeneration and adrenocortical insufficiency involving the primary ABCD1 defect, environmental factors and modifier genes. Important information has been derived from the X-ALD mouse models; species differences however complicate the interpretation of results. So far, bone marrow transplantation is the only effective long-term treatment for childhood cerebral X-ALD, however, only when performed at an early-stage of disease. Urgently needed novel therapeutic strategies are under consideration ranging from dietary approaches to gene therapy.
Comments [show]
None has been submitted yet.
No. Sentence Comment
94 Two X-ALD disease mutations located in the C-terminal half of ALDP (P484R and R591Q) affect both homo- and heterodimerization of ALDP [40].
X
ABCD1 p.Arg591Gln 16949688:94:78
status: NEW[hide] Adrenoleukodystrophy: subcellular localization and... J Neurochem. 2007 Jun;101(6):1632-43. Takahashi N, Morita M, Maeda T, Harayama Y, Shimozawa N, Suzuki Y, Furuya H, Sato R, Kashiwayama Y, Imanaka T
Adrenoleukodystrophy: subcellular localization and degradation of adrenoleukodystrophy protein (ALDP/ABCD1) with naturally occurring missense mutations.
J Neurochem. 2007 Jun;101(6):1632-43., [PMID:17542813]
Abstract [show]
Mutation in the X-chromosomal adrenoleukodystrophy gene (ALD; ABCD1) leads to X-linked adrenoleukodystrophy (X-ALD), a severe neurodegenerative disorder. The encoded adrenoleukodystrophy protein (ALDP/ABCD1) is a half-size peroxisomal ATP-binding cassette protein of 745 amino acids in humans. In this study, we chose nine arbitrary mutant human ALDP forms (R104C, G116R, Y174C, S342P, Q544R, S606P, S606L, R617H, and H667D) with naturally occurring missense mutations and examined the intracellular behavior. When expressed in X-ALD fibroblasts lacking ALDP, the expression level of mutant His-ALDPs (S606L, R617H, and H667D) was lower than that of wild type and other mutant ALDPs. Furthermore, mutant ALDP-green fluorescence proteins (S606L and H667D) stably expressed in CHO cells were not detected due to rapid degradation. Interestingly, the wild type ALDP co-expressed in these cells also disappeared. In the case of X-ALD fibroblasts from an ALD patient (R617H), the mutant ALDP was not detected in the cells, but appeared upon incubation with a proteasome inhibitor. When CHO cells expressing mutant ALDP-green fluorescence protein (H667D) were cultured in the presence of a proteasome inhibitor, both the mutant and wild type ALDP reappeared. In addition, mutant His-ALDP (Y174C), which has a mutation between transmembrane domain 2 and 3, did not exhibit peroxisomal localization by immunofluorescense study. These results suggest that mutant ALDPs, which have a mutation in the COOH-terminal half of ALDP, including S606L, R617H, and H667D, were degraded by proteasomes after dimerization. Further, the region between transmembrane domain 2 and 3 is important for the targeting of ALDP to the peroxisome.
Comments [show]
None has been submitted yet.
No. Sentence Comment
238 Actually, in their experiments the mutation of P484R and R591Q reduced the interaction of the COOH-terminal half of ALDP.
X
ABCD1 p.Arg591Gln 17542813:238:57
status: NEW[hide] Functional characterization of the adrenoleukodyst... Endocr Res. 2002 Nov;28(4):741-8. Gartner J, Dehmel T, Klusmann A, Roerig P
Functional characterization of the adrenoleukodystrophy protein (ALDP) and disease pathogenesis.
Endocr Res. 2002 Nov;28(4):741-8., [PMID:12530690]
Abstract [show]
X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder characterized by abnormal accumulation of saturated very long chain fatty acids in tissues and body fluids with predominance in brain white matter and adrenal cortex. The clinical phenotype is highly variable ranging from the severe childhood cerebral form to asymptomatic persons. The responsible ALD gene encodes the adrenoleukodystrophy protein (ALDP), a peroxisomal integral membrane protein that is a member of the ATP-binding cassette (ABC) transporter protein family. The patient gene mutations are heterogeneously distributed over the functional domains of ALDP. The extreme variability in clinical phenotype, even within one affected family, indicates that besides the ALD gene mutations other factors strongly influence the clinical phenotype. To understand the cell biology and function of mammalian peroxisomal ABC transporters and to determine their role in the pathogenesis of X-ALD we developed a system for expressing functional ABC protein domains in fusion with the maltose binding protein. Wild type and mutant fusion proteins of the nucleotide-binding fold were overexpressed, purified, and characterized by photoaffinity labeling with 8-azido ATP or 8-azido GTP and a coupled ATP regenerating enzyme assay for ATPase activity. Our studies provide evidence that peroxisomal ABC transporters utilize ATP to become a functional transporter and that ALD gene mutations alter peroxisomal transport function. The established disease model will be used further to study the influence of possible disease modifier proteins on ALDP function.
Comments [show]
None has been submitted yet.
No. Sentence Comment
41 The mutant constructs included missense mutations of patients with X-ALD in the nucleotide binding fold regions Walker A and 19mer (ALDP-NBF-G512S, ALDP-NBF-Q544R, ALDP-NBF-P560L, ALDP-NBF-R591Q, ALDP-NBF-S606L, and ALDP-NBF-D629H) and corresponding mutations in another ABC transporter in the peroxisome membrane, the 70 kDa peroxisomal membrane protein (PMP70; PMP70-NBF-G478R, PMP70- NBF-S572I).
X
ABCD1 p.Arg591Gln 12530690:41:189
status: NEW[hide] Altered expression of ALDP in X-linked adrenoleuko... Am J Hum Genet. 1995 Aug;57(2):292-301. Watkins PA, Gould SJ, Smith MA, Braiterman LT, Wei HM, Kok F, Moser AB, Moser HW, Smith KD
Altered expression of ALDP in X-linked adrenoleukodystrophy.
Am J Hum Genet. 1995 Aug;57(2):292-301., [PMID:7668254]
Abstract [show]
X-linked adrenoleukodystrophy (ALD) is a neurodegenerative disorder with variable phenotypic expression that is characterized by elevated plasma and tissue levels of very long-chain fatty acids. However, the product of the gene defective in ALD (ALDP) is a membrane transporter of the ATP-binding cassette family of proteins and is not related to enzymes known to activate or oxidize fatty acids. We generated an antibody that specifically recognizes the C-terminal 18 amino acids of ALDP and can detect ALDP by indirect immunofluorescence. To better understand the mechanism by which mutations in ALDP lead to disease, we used this antibody to examine the subcellular distribution and relative abundance of ALDP in skin fibroblasts from normal individuals and ALD patients. Punctate immunoreactive material typical of fibroblast peroxisomes was observed in cells from seven normal controls and eight non-ALD patients. Of 35 ALD patients tested, 17 had the childhood-onset cerebral form of the disease, 13 had the milder adult phenotype adrenomyeloneuropathy, 3 had adrenal insufficiency only, and 2 were affected fetuses. More than two-thirds (69%) of all patients studied showed no punctate immunoreactive material. There was no correlation between the immunofluorescence pattern and clinical phenotype. We determined the mutation in the ALD gene in 15 of these patients. Patients with either a deletion or frameshift mutation lacked ALDP immunoreactivity, as expected. Four of 11 patients with missense mutations were also immunonegative, indicating that these mutations affected the stability or localization of ALDP. In the seven immunopositive patients with missense mutations, correlation of the location and nature of the amino acid substitution may provide new insights into the function of this peroxisomal membrane protein. Furthermore, the study of female relatives of immunonegative ALD probands may aid in the assessment of heterozygote status.
Comments [show]
None has been submitted yet.
No. Sentence Comment
176 In 11 patients, missense mutations that occurred throughout the protein were found: within the transmembrane domains (patients 1, 3, and 4), within the ATP-binding domain (patients 8-12), and on either side of the ATP-binding Table 3 Mutational Analysis of the ALD Gene in IS Unrelated Patients ALDP Patient Phenotype Mutation Consequence Immunoreactivity 1 .................. CALD 825 A-GG K276E + 2.................. AMN 870-2AGAGE291,& 3 .................. CALD 872 G-C E291D 4 .................. AMN 1023 T-IC S342P+ 5 .................. AMN 1166 G-C R389H + 6 .................. CALD 1201 G-AA R401Q + 7 ........ CALD 1415-6 AAG FS@472 8 ........ AMN 1771 G-AA R591Q + 9 ........ Addison 1817 C-T S606L + 10 ................ AMN 1850 G-AA R617H 11 ................ CALD 1876 G-AA A626T 12 ................ Fetus 1884 G-C D629H + 13 ................ CALD 1932 C-UT Q645X 14 ................ AMN 1978 C-OT R660W 15 ........ AMN AExon7-10 Null Mutations in the ALD gene were determined, as described in Methods, in 15 of the ALD patients reported in table 2.
X
ABCD1 p.Arg591Gln 7668254:176:669
status: NEW178 In 11 patients, missense mutations that occurred throughout the protein were found: within the transmembrane domains (patients 1, 3, and 4), within the ATP-binding domain (patients 8-12), and on either side of the ATP-binding Table 3 Mutational Analysis of the ALD Gene in IS Unrelated Patients ALDP Patient Phenotype Mutation Consequence Immunoreactivity 1 .................. CALD 825 A-GG K276E + 2 .................. AMN 870-2 AGAG E291,& 3 .................. CALD 872 G-C E291D 4 .................. AMN 1023 T-IC S342P + 5 .................. AMN 1166 G-C R389H + 6 .................. CALD 1201 G-AA R401Q + 7 ........ CALD 1415-6 AAG FS@472 8 ........ AMN 1771 G-AA R591Q + 9 ........ Addison 1817 C-T S606L + 10 ................ AMN 1850 G-AA R617H 11 ................ CALD 1876 G-AA A626T 12 ................ Fetus 1884 G-C D629H + 13 ................ CALD 1932 C-UT Q645X 14 ................ AMN 1978 C-OT R660W 15 ........ AMN AExon7-10 Null Mutations in the ALD gene were determined, as described in Methods, in 15 of the ALD patients reported in table 2.
X
ABCD1 p.Arg591Gln 7668254:178:673
status: NEW[hide] Suppression of peroxisomal membrane protein defect... Hum Mol Genet. 1998 Feb;7(2):239-47. Braiterman LT, Zheng S, Watkins PA, Geraghty MT, Johnson G, McGuinness MC, Moser AB, Smith KD
Suppression of peroxisomal membrane protein defects by peroxisomal ATP binding cassette (ABC) proteins.
Hum Mol Genet. 1998 Feb;7(2):239-47., [PMID:9425230]
Abstract [show]
X-Linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder characterized by reduced peroxisomal very long chain fatty acid (VLCFA) beta-oxidation. The X - ALD gene product (ALDP) is a peroxisomal transmembrane protein with an ATP binding cassette (ABC). ALDP and three other ABC proteins (PMP70, ALDR, P70R) localize to the peroxisomal membrane. The function of this family of peroxisomal membrane proteins is unknown. We used complementation studies to begin analysis of their role in VLCFA beta-oxidation and on the peroxisomal membrane. Expression of either ALDP or PMP70 restores VLCFA beta-oxidation in X-ALD fibroblasts, indicating overlapping functions. Their expression also restores peroxisome biogenesis in cells that are deficient in the peroxisomal membrane protein Pex2p. Thus it is likely that complex protein interactions are involved in the function and biogenesis of peroxisomal membranes that may contribute to disease heterogeneity.
Comments [show]
None has been submitted yet.
No. Sentence Comment
184 Mutant ALDP cDNAs were generated by TA cloning (Invitrogen) of RT-PCR products generated from RNA isolated from patient fibroblast cell lines harboring either the R617H mutation that both destablizes and inactivates ALDP or the missense mutation R591Q that inactivates ALDP without altering stability of the protein (5).
X
ABCD1 p.Arg591Gln 9425230:184:246
status: NEW183 Mutant ALDP cDNAs were generated by TA cloning (Invitrogen) of RT-PCR products generated from RNA isolated from patient fibroblast cell lines harboring either the R617H mutation that both destablizes and inactivates ALDP or the missense mutation R591Q that inactivates ALDP without altering stability of the protein (5).
X
ABCD1 p.Arg591Gln 9425230:183:246
status: NEW185 Mutant ALDP cDNAs were generated by TA cloning (Invitrogen) of RT-PCR products generated from RNA isolated from patient fibroblast cell lines harboring either the R617H mutation that both destablizes and inactivates ALDP or the missense mutation R591Q that inactivates ALDP without altering stability of the protein (5).
X
ABCD1 p.Arg591Gln 9425230:185:246
status: NEW[hide] Preferential expression of mutant ABCD1 allele is ... Orphanet J Rare Dis. 2012 Jan 26;7:10. doi: 10.1186/1750-1172-7-10. Salsano E, Tabano S, Sirchia SM, Colapietro P, Castellotti B, Gellera C, Rimoldi M, Pensato V, Mariotti C, Pareyson D, Miozzo M, Uziel G
Preferential expression of mutant ABCD1 allele is common in adrenoleukodystrophy female carriers but unrelated to clinical symptoms.
Orphanet J Rare Dis. 2012 Jan 26;7:10. doi: 10.1186/1750-1172-7-10., [PMID:22280810]
Abstract [show]
BACKGROUND: Approximately 20% of adrenoleukodystrophy (X-ALD) female carriers may develop clinical manifestations, typically consisting of progressive spastic gait, sensory deficits and bladder dysfunctions. A skewing in X Chromosome Inactivation (XCI), leading to the preferential expression of the X chromosome carrying the mutant ABCD1 allele, has been proposed as a mechanism influencing X-linked adrenoleukodystrophy (X-ALD) carrier phenotype, but reported data so far are conflicting. METHODS: To shed light into this topic we assessed the XCI pattern in peripheral blood mononuclear cells (PBMCs) of 30 X-ALD carriers. Since a frequent problem with XCI studies is the underestimation of skewing due to an incomplete sample digestion by restriction enzymes, leading to variable results, we developed a pyrosequencing assay to identify samples completely digested, on which to perform the XCI assay. Pyrosequencing was also used to quantify ABCD1 allele-specific expression. Moreover, very long-chain fatty acid (VLCFA) levels were determined in the same patients. RESULTS: We found severely (>/=90:10) or moderately (>/=75:25) skewed XCI in 23 out of 30 (77%) X-ALD carriers and proved that preferential XCI is mainly associated with the preferential expression of the mutant ABCD1 allele, irrespective of the manifestation of symptoms. The expression of mutant ABCD1 allele also correlates with plasma VLCFA concentrations. CONCLUSIONS: Our results indicate that preferential XCI leads to the favored expression of the mutant ABCD1 allele. This emerges as a general phenomenon in X-ALD carriers not related to the presence of symptoms. Our data support the postulated growth advantage of cells with the preferential expression of the mutant ABCD1 allele, but argue against the use of XCI pattern, ABCD1 allele-specific expression pattern and VLCFA plasma concentration as biomarkers to predict the development of symptoms in X-ALD carriers.
Comments [show]
None has been submitted yet.
No. Sentence Comment
53 All samples were tested in Table 1 Clinical Findings, Genotype, X-Chromosome Inactivation (XCI), ABCD1 Allele-Specific Expression (ASE) and Biochemical Findings (VLCFA plasma levels) of X-ALD carriers Nr of family, consultants Age (yrs) Presence of symptoms (age at onset, yrs) Mutations XCI pattern ABCD1 ASE (mut:wt) C26 (nv) C26/C22 (nv) C24/C22 (nv) F1 II-3 67 Yes (45) 410G > A W137X 97:03 84:16 1,09 (<0,75) 48 (<17) 1644 (<1100) F1 III-2 34 No 410G > A W137X 91:09 nd 0,58 (<0,75) 47 (<17) 1482 (<1100) F2 I-2 61 Yes (59) 427C > G P143A 71:29 93:07 0,85 (<0,75) 18 (<17) 1222 (<1100) F2 II-1 38 No 427C > G P143A 85:15 83:17 nd nd nd F2 II-2 35 No 427C > G P143A 76:24 77:23 nd nd nd F3 II-2 73 Yes (45) 428C > A P143H 60:40 38:62 1,45 (<1,50) 28 (<40) 700 (<820) F3 III.1 46 No 428C > A P143H 84:16 84:16 1,53 (<1,50) 40 (<40) 860 (<820) F3 III-2 50 No 428C > A P143H 83:17 75:25 1,75 (<1,50) 37 (<40) 733 (<820) F4 II-3 75 Yes (50) 652C > T; 664G > T P218S; V222L 81:19 82:18 1,57 (<0,75) 19 (<17) 1680 (<1100) F4 III-1 44 No 652C > T; 664G > T P218S; V222L 83:17 81:19 2,38 (<1,50) 53 (<40) 1424 (<820) F4 III-3 45 Yes (29) 652C > T; 664G > T P218S; V222L 89:11 82:18 1,00 (<0,75) 36 (<17) 1611 (<1100) F5 II-1 55 Yes (54) 1202G > A R401Q 98:02 82:18 1,96 (<1,50) 38 (<40) 1031 (<820) F6 II-1 76 Yes (58) 1727T > C L576P 73:27 76:24 2,10 (<0,75) 21 (<17) 1039 (<1100) F7 I-2 72 No 1772G > A R591Q n/a n/a 1,23 (<1,5) 16 (<40) 798 (<820) F7 II-1 44 Yes (34) 1772G > A R591Q 96:04 97:03 2,7 (<1,50) 56 (<40) 957 (<820) F8 II-1 62 Yes (40) 1992G > A W664X 83:17 82:18 3,08 (<1,50) 56 (<40) 1132 (<820) F9 II-1 63 No 293C > T S98L 83:17 93:07 1,82 (<1,50) 37 (<40) 888 (<820) F9 II-3 57 No 293C > T S98L 79:21 75:25 1,99 (<1,50) 42 (<40) 913 (<820) F9 III-2 20 No 293C > T S98L 75:25 61:39 2,65 (<1,50) 46 (<40) 1149 (<820) F10 I-2 63 No 443A > G N148S 86:14 42:58 2,16 (<1,50) 42 (<40) 788 (<820) F10 II-2 40 No 443A > G N148S 96:04 84:16 2,17 (<1,50) 43 (<40) 757 (<820) F11 III-1 67 No 1165C > T R389C 52:48 72:28 0,7 (<1,50) 13 (<40) 572 (<820) F11 III-3 64 No 1165C > T R389C 78:22 34:66 1,1 (<1,50) 16 (<40) 823 (<820) F11 III-5 49 No 1165C > T R389C 98:02 20:80 1,05 (<1,50) 16 (<40) 848 (<820) F11 III-6 46 No 1165C > T R389C 71:29 74:26 1,30 (<1,50) 18 (<40) 1000 (<820) F11 V-1 26 No 1165C > T R389C 57:43 58:42 0,68 (<1,50) 14 (<40) 663 (<820) F12 I-2 53 No 1211C > A S404X 95:05 09:91 nd nd nd F13 I-2 60 No del. ex8-10 n/a 76:24 nd nd nd nd duplicate and one male DNA sample was included in each experiment as a control for enzymatic digestion.
X
ABCD1 p.Arg591Gln 22280810:53:1402
status: NEWX
ABCD1 p.Arg591Gln 22280810:53:1478
status: NEW[hide] ABCD1 mutations and phenotype distribution in Chin... Gene. 2013 Jun 10;522(1):117-20. doi: 10.1016/j.gene.2013.03.067. Epub 2013 Apr 5. Niu YF, Ni W, Wu ZY
ABCD1 mutations and phenotype distribution in Chinese patients with X-linked adrenoleukodystrophy.
Gene. 2013 Jun 10;522(1):117-20. doi: 10.1016/j.gene.2013.03.067. Epub 2013 Apr 5., [PMID:23566833]
Abstract [show]
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.
Comments [show]
None has been submitted yet.
No. Sentence Comment
74 Exon Nucleotide change Amino acid change Phenotype P1 None None None CCALD P2 7 c.1661G>A p.Arg554His CCALD P3 5 c.1477_1488 + 11del 23 p.Leu493_Arg496del Adolescent ALD P4 2 c.1028G>T p.Gly343Val CCALD P5 6 c.1553G>A p.Arg518Gln CCALD P6 5 c.1415_16delAG p.Gln472fsX83 CCALD P7 6 c.1534G>A p.Gly512Ser Adolescent ALD P8 7 c.1679C>T p.Pro560Leu CCALD P9 7 c.1772G>A p.Arg591Gln ACALD P10 5 c.1415_16delAG p.Gln472fsX83 ACALD Fig. 1.
X
ABCD1 p.Arg591Gln 23566833:74:368
status: NEW