Biomedical subjects

Garry R Cutting

Publications and source records attributed to Garry R Cutting.

At least 19 recordsLinked to original sources

PubMed2006

Variants in mannose-binding lectin and tumour necrosis factor alpha affect survival in cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis with the same mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene differ widely in survival suggesting other factors have a substantial role in mortality. OBJECTIVE: To determine if the genotype distribution of variants in three putative cystic fibrosis modifier genes (tumour necrosis factor alpha (TNFalpha), transforming growth factor beta1 (TGFbeta1) or mannose-binding lectin (MBL2)) differed among patients with cystic fibrosis grouped according to age and survival status. METHODS: Genotypes of four variants (TNFalpha-238, TNFalpha-308, TGFbeta1-509 and MBL2 O) were determined in three groups of Caucasians from a single medical centre: 101 children with cystic fibrosis (aged <17 years; mean age 9.4 years), 115 adults with cystic fibrosis (aged > or =17 years; mean age 30.8 years) and 38 non-surviving adults with cystic fibrosis (21 deceased and 17 lung transplant after 17 years of age). Genotypes of 127 healthy Caucasians in the same geographical region were used as controls. Kaplan-Meier and Cox hazard regression were used to evaluate the genotype effect on cumulative survival. RESULTS: Genotype frequencies among adults and children with cystic fibrosis differed for TNFalpha-238 (G/G vs G/A; p = 0.022) and MBL2 (A/A vs O/O; p = 0.016). When adults with cystic fibrosis were compared to non-surviving adults with cystic fibrosis, genotype frequencies of both genes differed (TNFalpha-238G/G vs G/A; p = 0.0015 and MBL2: A/A vs O/O; p = 0.009). The hazard ratio for TNFalpha-238G/G vs G/A was 0.25 (95% CI 0.06 to 1.0, p = 0.04) and for MBL2 O/O vs A/A or A/O was 2.5 (95% CI 1.3 to 4.9, p = 0.007). CONCLUSIONS: TNFalpha-238 G/A and MBL2 O/O genotypes appear to be genetic modifiers of survival of cystic fibrosis.

Adolescent↗

PubMed2006

Relative contribution of genetic and nongenetic modifiers to intestinal obstruction in cystic fibrosis.

BACKGROUND & AIMS: Neonatal intestinal obstruction (meconium ileus [MI]) occurs in 15% of patients with cystic fibrosis (CF). Our aim was to determine the relative contribution of genetic and nongenetic modifiers to the development of this major complication of CF. METHODS: A total of 65 monozygous twin pairs, 23 dizygous twin/triplet sets, and 349 sets of siblings with CF were analyzed for MI status, significant covariates, and genome-wide linkage. RESULTS: Specific mutations in the CF transmembrane conductance regulator (CFTR), the gene responsible for CF, correlated with MI, indicating a role for CFTR genotype. Monozygous twins showed substantially greater concordance for MI than dizygous twins and siblings (P = 1 x 10(-5)), showing that modifier genes independent of CFTR contribute substantially to this trait. Regression analysis revealed that MI was correlated with distal intestinal obstruction syndrome (P = 8 x 10(-4)). Unlike MI, concordance analysis indicated that the risk for development of distal intestinal obstruction syndrome in CF patients is caused primarily by nongenetic factors. Regions of suggestive linkage (logarithm of the odds of linkage >2.0) for modifier genes that cause MI (chromosomes 4q35.1, 8p23.1, and 11q25) or protect from MI (chromosomes 20p11.22 and 21q22.3) were identified by genome-wide analyses. These analyses did not support the existence of a major modifier gene on chromosome 19 in a region previously linked to MI. CONCLUSIONS: The CFTR gene along with 2 or more modifier genes are the major determinants of intestinal obstruction in newborn CF patients, whereas intestinal obstruction in older CF patients is caused primarily by nongenetic factors.

Chromosomes, Human, Pair 11↗

PubMed2006

Gross genomic rearrangements involving deletions in the CFTR gene: characterization of six new events from a large cohort of hitherto unidentified cystic fibrosis chromosomes and meta-analysis of the underlying mechanisms.

Gross genomic rearrangements involving deletions in the CFTR gene have recently been found to account for approximately 20% of unidentified cystic fibrosis (CF) chromosomes in both French and Italian patients. Using QMPSF and walking quantitative DHPLC, six novel mutations (three simple deletions, two complex deletions with short insertions of 3-6 bp, and a complex deletion with a 182 bp inverted downstream sequence) were characterized by screening 274 unidentified CF chromosomes from 10 different countries. These lesions increase the total number of fully characterized large CFTR genomic rearrangements involving deletions to 21. Systematic analysis of the 42 associated breakpoints indicated that all 21 events were caused by nonhomologous recombination. Whole gene complexity analysis revealed a significant correlation between regions of low sequence complexity and the locations of the deletion breakpoints. Known recombination-promoting motifs were noted in the vicinity of the breakpoints. A total of 11 simple deletions were potentially explicable in terms of the classical model of replication slippage. However, the complex deletions appear to have arisen via multiple mechanisms; three of the five complex deletions with short insertions and both examples of large inverted insertions (299 and 182 bp, respectively) can be explained by either a model of serial replication slippage in cis (SRScis) or SRS in trans (SRStrans). Finally, the nature and distribution of large genomic rearrangements in the CFTR gene were compared and contrasted with those of two other genes, DMD and MSH2, with a view to gaining a broader understanding of DNA sequence context in mediating the diverse underlying mutational mechanisms.

Base Sequence↗

PubMed2005

Mutations in the beta-subunit of the epithelial Na+ channel in patients with a cystic fibrosis-like syndrome.

Cystic fibrosis (CF) is an autosomal recessive disorder of Cl(-) and Na(+) transport. The vast majority of CF patients have deleterious mutations in an epithelial Cl(-) channel called the CF transmembrane conductance regulator (CFTR). In contrast, defects in the epithelial Na(+) channel (SCNN1) have been associated with phenotypes dominated by renal disease (systemic pseudohypoaldosteronism type I and Liddle syndrome). We report two non-classic CF patients without CFTR mutations who have novel deleterious mutations in the beta-subunits of SCNN1 in the absence of overt renal disease.

Adult↗

PubMed2005

PDZ-binding motifs are unable to ensure correct polarized protein distribution in the absence of additional localization signals.

The C-terminal PDZ-binding motifs are required for polarized apical/basolateral localization of many membrane proteins. To determine the specificity of the PDZ-binding motifs in establishing cellular distribution, we utilized a 111-amino acid region from the C-terminus of cystic fibrosis transmembrane conductance regulator (CFTR) that is able to direct apical localization of fused reporter proteins. Substitution of the C-terminal PDZ-binding motif of CFTR with corresponding motifs necessary for basolateral localization of other membrane proteins did not lead to the redistribution of the fusion protein to the basolateral membrane. Instead, some fusion proteins remained localized to the apical membrane, whereas others showed no specific distribution. The specificity of the PDZ-based interactions was substantially increased when specific amino acids located upstream of the classical PDZ-binding motifs were included. However, even the presence of a longer C-terminal motif from a basolateral protein could not ensure basolateral distribution of the fusion protein. Our results indicate that the C-terminal PDZ-binding motifs are not the primary signals for polarized protein distribution, although they are required for targeting and/or stabilization of protein at the given location.

Amino Acid Motifs↗

PubMed2005

Increased prevalence of chronic rhinosinusitis in carriers of a cystic fibrosis mutation.

OBJECTIVE: To explore whether there is an increased prevalence of chronic rhinosinusitis (CRS) in known cystic fibrosis (CF) carriers. Self-reported CRS affects 13% to 14% of the US population and clusters in families, which suggests that genetic factors may play an etiologic role. Cystic fibrosis is an inherited recessive disorder that invariably affects the sinuses. The frequency of CF mutations has been reported to be higher in patients with CRS than in unaffected controls. PATIENTS: Obligate CF carriers (parents of patients with CF) were recruited from the Johns Hopkins CF clinic. The presence of signs and symptoms of CRS was assessed by a sinus disease questionnaire. A subgroup of participants was evaluated by a physician experienced in the diagnosis of CRS. RESULTS: Fifty-three (36%) of 147 obligate CF carriers who returned a completed questionnaire had self-reported CRS. Twenty-three CF carriers (14 with and 9 without CRS based on self-reporting in the questionnaire) were clinically evaluated. Seven were diagnosed as having CRS (all 7 with self-reported CRS), while another 6 had allergic rhinitis or recurrent acute rhinosinusitis (all 6 with self-reported CRS), and 10 had no evidence of active sinus disease (1 with self-reported CRS). The sensitivity (100%) and specificity (56%) of the questionnaire for physician-diagnosed CRS was similar to that of other survey instruments used to estimate the prevalence of self-reported CRS in the general population. CONCLUSION: Carriers of a single CF mutation have a higher prevalence of CRS than the general population.

Case-Control Studies↗

PubMed2005

Phenotypic and genetic characterization of patients with features of "nonclassic" forms of cystic fibrosis.

OBJECTIVE: To determine which features of incomplete or "nonclassic" forms of cystic fibrosis (CF) are associated with deleterious CF transmembrane conductance regulator gene ( CFTR ) mutations, and to explore other etiologies for features not associated with deleterious CFTR mutations. STUDY DESIGN: Clinical features were compared between 57 patients with deleterious mutations in each CFTR and 63 with no deleterious mutations. The Shwachman Bodian Diamond syndrome gene ( SBDS ) was sequenced to search for mutations in patients with no deleterious CFTR mutations and steatorrhea to determine if any had unrecognized Shwachman-Diamond syndrome (SDS). RESULTS: The presence of a common CF-causing mutation, absence of the vas deferens, and Pseudomona aeruginosa in the sputum correlated with the presence of two deleterious CFTR mutations, whereas sweat chloride concentration, diagnostic criteria for CF, and steatorrhea did not. However, sweat chloride concentration correlated with CFTR mutation status in patients infected with P aeruginosa. One patient had disease-causing mutations in each SBDS . CONCLUSIONS: Presence of a common CF-causing mutation, absence of the vas deferens and/or P aeruginosa infection in a patient with features of nonclassic CF are predictive of deleterious mutations in each CFTR , whereas steatorrhea in the same context is likely to have etiologies other than CF transmembrane conductance regulator (CFTR) dysfunction.

Adult↗

PubMed2005

Lack of association of common cystic fibrosis transmembrane conductance regulator gene mutations with primary sclerosing cholangitis.

BACKGROUND: Primary sclerosing cholangitis (PSC) is a chronic progressive cholestatic liver disease of uncertain etiology. However, the histologic features of PSC liver disease can resemble those in cystic fibrosis (CF), an inherited disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. We sought to determine if PSC patients have a higher frequency of common CF alleles than disease controls. METHODS: DNA was extracted from peripheral lymphocytes of patients with end-stage liver disease. Samples were obtained before liver transplantation from 59 PSC patients and from three groups of control patients (20 each with primary biliary cirrhosis, autoimmune hepatitis, or hepatitis C). DNA samples were genotyped for 32 common CF mutations, the intron 8 T tract variants, and the M470V variant. RESULTS: One of 59 PSC patients (1.7%) had the common CF mutation (DeltaF508) in one CFTR gene. Two controls (3.3%) carried a single CF mutation (DeltaF508 in one primary biliary cirrhosis patient; W1282X in one hepatitis C patient). These rates do not differ from expected in the general population. The frequency of CFTR variants (5T and M470V) was also similar between PSC patients and controls. CONCLUSIONS: Despite anatomical similarities between CF liver disease and PSC, we could not confirm that PSC patients carried common CF mutations or common CFTR variants in higher than expected frequencies. These data suggest that CFTR dysfunction does not influence the pathogenesis of PSC.

Adult↗

PubMed2005

Modifier genetics: cystic fibrosis.

Cystic fibrosis (CF) is the most common lethal autosomal recessive disorder in the Caucasian population, affecting about 30,000 individuals in the United States. The gene responsible for CF, the CF transmembrane conductance regulator (CFTR), was identified 15 years ago. Substantial variation in the many aspects of the CF phenotype among individuals with the same CFTR genotype demonstrates that factors independent of CFTR exert considerable influence on outcome in CF. To date, the majority of published studies investigating the cause of disease variability in CF report associations between candidate genes and some aspect of the CF phenotype. However, a definitive modifier gene for CF remains to be identified. Despite the challenges posed by searches for modifier effects, studies of affected twins and siblings indicate that genetic factors play a substantial role in intestinal manifestations. Identifying the factors contributing to variation in pulmonary disease, the primary cause of mortality, remains a challenge for CF research.

Cystic Fibrosis↗

PubMed2004

A variable dinucleotide repeat in the CFTR gene contributes to phenotype diversity by forming RNA secondary structures that alter splicing.

Dinucleotide repeats are ubiquitous features of eukaryotic genomes that are not generally considered to have functional roles in gene expression. However, the highly variable nature of dinucleotide repeats makes them particularly interesting candidates for modifiers of RNA splicing when they are found near splicing signals. An example of a variable dinucleotide repeat that affects splicing is a TG repeat located in the splice acceptor of exon 9 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Higher repeat numbers result in reduced exon 9 splicing efficiency and, in some instances, the reduction in full-length transcript is sufficient to cause male infertility due to congenital bilateral absence of the vas deferens or nonclassic cystic fibrosis. Using a CFTR minigene system, we studied TG tract variation and observed the same correlation between dinucleotide repeat number and exon 9 splicing efficiency seen in vivo. Replacement of the TG dinucleotide tract in the minigene with random sequence abolished splicing of exon 9. Replacements of the TG tract with sequences that can self-base-pair suggested that the formation of an RNA secondary structure was associated with efficient splicing. However, splicing efficiency was inversely correlated with the predicted thermodynamic stability of such structures, demonstrating that intermediate stability was optimal. Finally, substitution with TA repeats of differing length confirmed that stability of the RNA secondary structure, not sequence content, correlated with splicing efficiency. Taken together, these data indicate that dinucleotide repeats can form secondary structures that have variable effects on RNA splicing efficiency and clinical phenotype.

Base Sequence↗

PubMed2004

Quantitative methods for the analysis of CFTR transcripts/splicing variants.

In cystic fibrosis (CF), transcript analysis and quantification are important for diagnosis, prognosis and also as surrogate markers for some therapies including gene therapy. Classical RNA-based methods require significant expression levels in target samples for appropriate analysis, thus PCR-based methods are evolving towards reliable quantification. Various protocols for the quantitative analysis of CFTR transcripts (including those resulting from splicing variants) are described and discussed here.

Cystic Fibrosis↗

PubMed2003

Variation in a repeat sequence determines whether a common variant of the cystic fibrosis transmembrane conductance regulator gene is pathogenic or benign.

An abbreviated tract of five thymidines (5T) in intron 8 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene is found in approximately 10% of individuals in the general population. When found in trans with a severe CFTR mutation, 5T can result in male infertility, nonclassic cystic fibrosis, or a normal phenotype. To test whether the number of TG repeats adjacent to 5T influences disease penetrance, we determined TG repeat number in 98 patients with male infertility due to congenital absence of the vas deferens, 9 patients with nonclassic CF, and 27 unaffected individuals (fertile men). Each of the individuals in this study had a severe CFTR mutation on one CFTR gene and 5T on the other. Of the unaffected individuals, 78% (21 of 27) had 5T adjacent to 11 TG repeats, compared with 9% (10 of 107) of affected individuals. Conversely, 91% (97 of 107) of affected individuals had 12 or 13 TG repeats, versus only 22% (6 of 27) of unaffected individuals (P<.00001). Those individuals with 5T adjacent to either 12 or 13 TG repeats were substantially more likely to exhibit an abnormal phenotype than those with 5T adjacent to 11 TG repeats (odds ratio 34.0, 95% CI 11.1-103.7, P<.00001). Thus, determination of TG repeat number will allow for more accurate prediction of benign versus pathogenic 5T alleles.

Base Sequence↗

PubMed2003

Evidence for asthma susceptibility genes on chromosome 11 in an African-American population.

Initial genome-wide scan data provided suggestive evidence for linkage of the asthma phenotype in African-American (AA), but not Caucasian, families to chromosome 11q markers (peak at D11S1985; LOD=2). To refine this region, mapping analysis of 91 AA families (51 multiplex families and 40 asthmatic case-parent trios) was performed with an additional 17 markers flanking the initial peak linkage marker. Multipoint analyses of the 51 multiplex families yielded significant evidence of linkage with a peak non-parametric linkage score of 4.38 at marker D11S1337 (map position 68.6 cM). Furthermore, family-based association and transmission disequilibrium tests conducted on all 91 families showed significant evidence of linkage in the presence of disequilibrium for several individual markers in this region. A putative susceptibility locus was estimated to be at map position 70.8 cM with a confidence interval spanning the linkage peak. Evidence from both linkage and association analyses suggest that this region of chromosome 11 contains one or more susceptibility genes for asthma in these AA families.

Adolescent↗

PubMed2002

Variant cystic fibrosis phenotypes in the absence of CFTR mutations.

BACKGROUND: Cystic fibrosis is a life-limiting autosomal recessive disorder with a highly variable clinical presentation. The classic form involves characteristic findings in the respiratory tract, gastrointestinal tract, male reproductive tract, and sweat glands and is caused by loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR ) gene. Nonclassic forms of cystic fibrosis have been associated with mutations that reduce but do not eliminate the function of the CFTR protein. We assessed whether alteration in CFTR function is responsible for the entire spectrum of variant cystic fibrosis phenotypes. METHODS: Extensive genetic analysis of the CFTR gene was performed in 74 patients with nonclassic cystic fibrosis who had been referred by 34 medical centers. We evaluated two families that each included a proband without identified mutations and a sibling with nonclassic cystic fibrosis to determine whether there was linkage to the CFTR locus and to measure the extent of CFTR function in the sweat gland and nasal epithelium. RESULTS: Of the 74 patients studied, 29 had two mutations in the CFTR gene, 15 had one mutation, and 30 had no mutations. A final genotype of two mutations was more common among patients who had been referred after screening for common cystic fibrosis-causing mutations identified one mutation than among those who had been referred after screening had identified no such mutations (26 of 34 patients vs. 3 of 40 patients, P<0.001). Comparison of clinical features and sweat chloride concentrations revealed no significant differences among patients with two, one, or no CFTR mutations. Haplotype analysis in the two families revealed no linkage to CFTR. Although each of the affected siblings had elevated sweat chloride concentrations, measurements of cyclic AMP-mediated ion and fluid transport in the sweat gland and nasal epithelium demonstrated the presence of functional CFTR. CONCLUSIONS: Factors other than mutations in the CFTR gene can produce phenotypes clinically indistinguishable from nonclassic cystic fibrosis caused by CFTR dysfunction.

Adolescent↗

PubMed2002

PDZ domain interaction controls the endocytic recycling of the cystic fibrosis transmembrane conductance regulator.

The C terminus of CFTR contains a PDZ interacting domain that is required for the polarized expression of cystic fibrosis transmembrane conductance regulator (CFTR) in the apical plasma membrane of polarized epithelial cells. To elucidate the mechanism whereby the PDZ interacting domain mediates the polarized expression of CFTR, Madin-Darby canine kidney cells were stably transfected with wild type (wt-CFTR) or C-terminally truncated human CFTR (CFTR-DeltaTRL). We tested the hypothesis that the PDZ interacting domain regulates sorting of CFTR from the Golgi to the apical plasma membrane. Pulse-chase studies in combination with domain-selective cell surface biotinylation revealed that newly synthesized wt-CFTR and CFTR-DeltaTRL were targeted equally to the apical and basolateral membranes in a nonpolarized fashion. Thus, the PDZ interacting domain is not an apical sorting motif. Deletion of the PDZ interacting domain reduced the half-life of CFTR in the apical membrane from approximately 24 to approximately 13 h but had no effect on the half-life of CFTR in the basolateral membrane. Thus, the PDZ interacting domain is an apical membrane retention motif. Next, we examined the hypothesis that the PDZ interacting domain affects the apical membrane half-life of CFTR by altering its endocytosis and/or endocytic recycling. Endocytosis of wt-CFTR and CFTR-DeltaTRL did not differ. However, endocytic recycling of CFTR-DeltaTRL was decreased when compared with wt-CFTR. Thus, deletion of the PDZ interacting domain reduced the half-life of CFTR in the apical membrane by decreasing CFTR endocytic recycling. Our results identify a new role for PDZ proteins in regulating the endocytic recycling of CFTR in polarized epithelial cells.

Amino Acid Motifs↗

PubMed2002

Aggregation of misfolded proteins can be a selective process dependent upon peptide composition.

Intracellular aggregation of misfolded proteins is observed in a number of human diseases, in particular, neurologic disorders in which expanded tracts of polyglutamine residues play a central role. A variety of other proteins are prone to aggregation when mutated, indicating that this process is a common pathologic mechanism for inherited disorders. However, little is known about the relationship between the sequence of aggregating peptides and the specificity of intracellular accumulation. Here we demonstrate that substitution of two residues eliminates aggregation of a 111-amino acid peptide derived from the C-terminal portion of the cystic fibrosis transmembrane conductance regulator (CFTR). We also show that fusion to a reporter protein considerably alters the subcellular distribution of aggregating peptide. When fused to green fluorescent protein, the peptide containing amino acids 1370-1480 of CFTR accumulates in large perinuclear or nuclear aggregates. The same CFTR fragment devoid of green fluorescent protein localizes predominantly to discrete accumulations associated with mitochondria. Importantly, both types of accumulation are dependent on the presence of the same two amino acids within the CFTR sequence. Co-expression studies show that both CFTR-derived proteins can co-localize in large cytoplasmic/nuclear aggregates. However, neither CFTR construct accumulates in intracellular inclusions formed by N-terminal fragment of huntingtin. In addition to unique accumulation patterns, each aggregating peptide shows differences in association with chaperone proteins. Thus, our results indicate that the process of intracellular aggregation can be a selective process determined by the composition of the aggregating peptides.

Amino Acid Sequence↗

PubMed2002

Atypical 5' splice sites cause CFTR exon 9 to be vulnerable to skipping.

The molecular basis of the skipping of constitutive exons in many messenger RNAs is not fully understood. A well-studied example is exon 9 of the human cystic fibrosis transmembrane conductance regulator gene (CFTR), in which an abbreviated polypyrimidine tract between the branch point A and the 3' splice site is associated with increased exon skipping and disease. However, many exons, both in CFTR and in other genes and have short polypyrimidine tracts in their 3' splice sites, yet they are not skipped. Inspection of the 5' splice sites immediately up- and downstream of exon 9 revealed deviations from consensus sequence, so we hypothesized that this exon may be inherently vulnerable to skipping. To test this idea, we constructed a CFTR minigene and replicated exon 9 skipping associated with the length of the polypyrimidine tract upstream of exon 9. We then mutated the flanking 5' splice sites and determined the effect on exon skipping. Conversion of the upstream 5' splice site to consensus by replacing a pyrimidine at position +3 with a purine resulted in increased exon skipping. In contrast, conversion of the downstream 5' splice site to consensus by insertion of an adenine at position +4 resulted in a substantial reduction in exon 9 skipping, regardless of whether the upstream 5' splice site was consensus or not. These results suggested that the native downstream 5' splice site plays an important role in CFTR exon 9 skipping, a hypothesis that was supported by data from sheep and mouse genomes. Although CFTR exon 9 in sheep is preceded by a long polypyrimidine tract (Y(14)), it skips exon 9 in vivo and has a nonconsensus downstream 5' splice site identical to that in humans. On the other hand, CFTR exon 9 in mice is preceded by a short polypyrimidine tract (Y(5)) but is not skipped in vivo. Its downstream 5' splice site differs from that in humans by a 2-nt insertion, which, when introduced into the human CFTR minigene, abolished exon 9 skipping. Taken together, these observations place renewed emphasis on deviations at 5' splice sites in nucleotides other than the invariant GT, particularly when such changes are found in conjunction with other altered splicing sequences, such as a shortened polypyrimidine tract. Thus, careful inspection of entire 5' splice sites may identify constitutive exons that are vulnerable to skipping.

Alternative Splicing↗

PubMed2002

Contiguous deletion of the X-linked adrenoleukodystrophy gene (ABCD1) and DXS1357E: a novel neonatal phenotype similar to peroxisomal biogenesis disorders.

X-linked adrenoleukodystrophy (X-ALD) results from mutations in ABCD1. ABCD1 resides on Xq28 and encodes an integral peroxisomal membrane protein (ALD protein [ALDP]) that is of unknown function and that belongs to the ATP-binding cassette-transporter superfamily. Individuals with ABCD1 mutations accumulate very-long-chain fatty acids (VLCFA) (carbon length >22). Childhood cerebral X-ALD is the most devastating form of the disease. These children have the earliest onset (age 7.2 +/- 1.7 years) among the clinical phenotypes for ABCD1 mutations, but onset does not occur at <3 years of age. Individuals with either peroxisomal biogenesis disorders (PBD) or single-enzyme deficiencies (SED) in the peroxisomal beta-oxidation pathway--disorders such as acyl CoA oxidase deficiency and bifunctional protein deficiency--also accumulate VLCFA, but they present during the neonatal period. Until now, it has been possible to distinguish unequivocally between individuals with these autosomal recessively inherited syndromes and individuals with ABCD1 mutations, on the basis of the clinical presentation and measurement of other biochemical markers. We have identified three newborn boys who had clinical symptoms and initial biochemical results consistent with PBD or SED. In further study, however, we showed that they lacked ALDP, and we identified deletions that extended into the promoter region of ABCD1 and the neighboring gene, DXS1357E. Mutations in DXS1357E and the ABCD1 promoter region have not been described previously. We propose that the term "contiguous ABCD1 DXS1357E deletion syndrome" (CADDS) be used to identify this new contiguous-gene syndrome. The three patients with CADDS who are described here have important implications for genetic counseling, because individuals with CADDS may previously have been misdiagnosed as having an autosomal recessive PBD or SED

ATP Binding Cassette Transporter, Subfamily D, Mem↗