Human Bacterial Artificial Chromosome (BAC) Transgenesis Fully Rescues Noradrenergic Function in Dopamine ß-Hydroxylase Knockout Mice.

Dopamine ß-hydroxylase (DBH) converts dopamine (DA) to norepinephrine (NE) in noradrenergic/adrenergic cells. DBH deficiency prevents NE production and causes sympathetic failure, hypotension and ptosis in humans and mice; DBH knockout (Dbh -/-) mice reveal other NE deficiency phenotypes including embryonic lethality, delayed growth, and behavioral defects. Furthermore, a single nucleotide polymorphism (SNP) in the human DBH gene promoter (-970C>T; rs1611115) is associated with variation in serum DBH activity and with several neurological- and neuropsychiatric-related disorders, although its impact on DBH expression is controversial. Phenotypes associated with DBH deficiency are typically treated with L-3,4-dihydroxyphenylserine (DOPS), which can be converted to NE by aromatic acid decarboxylase (AADC) in the absence of DBH. In this study, we generated transgenic mice carrying a human bacterial artificial chromosome (BAC) encompassing the DBH coding locus as well as ~45 kb of upstream and ~107 kb of downstream sequence to address two issues. First, we characterized the neuroanatomical, neurochemical, physiological, and behavioral transgenic rescue of DBH deficiency by crossing the BAC onto a Dbh -/- background. Second, we compared human DBH mRNA abundance between transgenic lines carrying either a "C" or a "T" at position -970. The BAC transgene drove human DBH mRNA expression in a pattern indistinguishable from the endogenous gene, restored normal catecholamine levels to the peripheral organs and brain of Dbh -/- mice, and fully rescued embryonic lethality, delayed growth, ptosis, reduced exploratory activity, and seizure susceptibility. In some cases, transgenic rescue was superior to DOPS. However, allelic variation at the rs1611115 SNP had no impact on mRNA levels in any tissue. These results indicate that the human BAC contains all of the genetic information required for tissue-specific, functional expression of DBH and can rescue all measured Dbh deficiency phenotypes, but did not reveal an impact of the rs11115 variant on DBH expression in mice.

Whole-exome sequencing identifies novel MPL and JAK2 mutations in triple-negative myeloproliferative neoplasms.

Essential thrombocythemia (ET) and primary myelofibrosis (PMF) are chronic diseases characterized by clonal hematopoiesis and hyperproliferation of terminally differentiated myeloid cells. The disease is driven by somatic mutations in exon 9 of CALR or exon 10 of MPL or JAK2-V617F in >90% of the cases, whereas the remaining cases are termed "triple negative." We aimed to identify the disease-causing mutations in the triple-negative cases of ET and PMF by applying whole-exome sequencing (WES) on paired tumor and control samples from 8 patients. We found evidence of clonal hematopoiesis in 5 of 8 studied cases based on clonality analysis and presence of somatic genetic aberrations. WES identified somatic mutations in 3 of 8 cases. We did not detect any novel recurrent somatic mutations. In 3 patients with clonal hematopoiesis analyzed by WES, we identified a somatic MPL-S204P, a germline MPL-V285E mutation, and a germline JAK2-G571S variant. We performed Sanger sequencing of the entire coding region of MPL in 62, and of JAK2 in 49 additional triple-negative cases of ET or PMF. New somatic (T119I, S204F, E230G, Y591D) and 1 germline (R321W) MPL mutation were detected. All of the identified MPL mutations were gain-of-function when analyzed in functional assays. JAK2 variants were identified in 5 of 57 triple-negative cases analyzed by WES and Sanger sequencing combined. We could demonstrate that JAK2-V625F and JAK2-F556V are gain-of-function mutations. Our results suggest that triple-negative cases of ET and PMF do not represent a homogenous disease entity. Cases with polyclonal hematopoiesis might represent hereditary disorders.

Molecular responses and chromosomal aberrations in patients with polycythemia vera treated with peg-proline-interferon alpha-2b.

Fifty-one polycythemia vera (PV) patients were enrolled in the phase I/II clinical study PEGINVERA to receive a new formulation of pegylated interferon alpha (peg-proline-IFNα-2b, AOP2014/P1101). Peg-proline-IFNα-2b treatment led to high response rates on both hematologic and molecular levels. Hematologic and molecular responses were achieved for 46 and 18 patients (90 and 35% of the whole cohort), respectively. Although interferon alpha (IFNα) is known to be an effective antineoplastic therapy for a long time, it is currently not well understood which genetic alterations influence therapeutic outcomes. Apart from somatic changes in specific genes, large chromosomal aberrations could impact responses to IFNα. Therefore, we evaluated the interplay of cytogenetic changes and IFNα responses in the PEGINVERA cohort. We performed high-resolution SNP microarrays to analyze chromosomal aberrations prior and during peg-proline-IFNα-2b therapy. Similar numbers and types of chromosomal aberrations in responding and non-responding patients were observed, suggesting that peg-proline-IFNα-2b responses are achieved independently of chromosomal aberrations. Furthermore, complete cytogenetic remissions were accomplished in three patients, of which two showed more than one chromosomal aberration. These results imply that peg-proline-IFNα-2b therapy is an effective drug for PV patients, possibly including patients with complex cytogenetic changes.

Common germline variation at the TERT locus contributes to familial clustering of myeloproliferative neoplasms.

The C allele of the rs2736100 single nucleotide polymorphism located in the second intron of the TERT gene has recently been identified as a susceptibility factor for myeloproliferative neoplasms (MPN) in the Icelandic population. Here, we evaluate the role of TERT rs2736100_C in sporadic and familial MPN in the context of the previously identified JAK2 GGCC predisposition haplotype. We have confirmed the TERT rs2736100_C association in a large cohort of Italian sporadic MPN patients. The risk conferred by TERT rs2736100_C is present in all molecular and diagnostic MPN subtypes. TERT rs2736100_C and JAK2 GGCC are independently predisposing to MPN and have an additive effect on disease risk, together explaining a large fraction of the population attributable fraction (PAF = 73.06%). We found TERT rs2736100_C significantly enriched (P = 0.0090) in familial MPN compared to sporadic MPN, suggesting that low-penetrance variants may be responsible for a substantial part of familial clustering in MPN.

The triggering receptor expressed on myeloid cells 2 inhibits complement component 1q effector mechanisms and exerts detrimental effects during pneumococcal pneumonia.

Phagocytosis and inflammation within the lungs is crucial for host defense during bacterial pneumonia. Triggering receptor expressed on myeloid cells (TREM)-2 was proposed to negatively regulate TLR-mediated responses and enhance phagocytosis by macrophages, but the role of TREM-2 in respiratory tract infections is unknown. Here, we established the presence of TREM-2 on alveolar macrophages (AM) and explored the function of TREM-2 in the innate immune response to pneumococcal infection in vivo. Unexpectedly, we found Trem-2(-/-) AM to display augmented bacterial phagocytosis in vitro and in vivo compared to WT AM. Mechanistically, we detected that in the absence of TREM-2, pulmonary macrophages selectively produced elevated complement component 1q (C1q) levels. We found that these increased C1q levels depended on peroxisome proliferator-activated receptor-δ (PPAR-δ) activity and were responsible for the enhanced phagocytosis of bacteria. Upon infection with S. pneumoniae, Trem-2(-/-) mice exhibited an augmented bacterial clearance from lungs, decreased bacteremia and improved survival compared to their WT counterparts. This work is the first to disclose a role for TREM-2 in clinically relevant respiratory tract infections and demonstrates a previously unknown link between TREM-2 and opsonin production within the lungs.

CALR exon 9 mutations are somatically acquired events in familial cases of essential thrombocythemia or primary myelofibrosis.

Somatic mutations in the calreticulin (CALR) gene were recently discovered in patients with sporadic essential thrombocythemia (ET) and primary myelofibrosis (PMF) lacking JAK2 and MPL mutations. We studied CALR mutation status in familial cases of myeloproliferative neoplasm. In a cohort of 127 patients, CALR indels were identified in 6 of 55 (11%) subjects with ET and in 6 of 20 (30%) with PMF, whereas 52 cases of polycythemia vera had nonmutated CALR. All CALR mutations were somatic, found in granulocytes but not in T lymphocytes. Patients with CALR-mutated ET showed a higher platelet count (P = .017) and a lower cumulative incidence of thrombosis (P = .036) and of disease progression (P = .047) compared with those with JAK2 (V617F). In conclusion, a significant proportion of familial ET and PMF nonmutated for JAK2 carry a somatic mutation of CALR.

JAK2 or CALR mutation status defines subtypes of essential thrombocythemia with substantially different clinical course and outcomes.

Patients with essential thrombocythemia may carry JAK2 (V617F), an MPL substitution, or a calreticulin gene (CALR) mutation. We studied biologic and clinical features of essential thrombocythemia according to JAK2 or CALR mutation status and in relation to those of polycythemia vera. The mutant allele burden was lower in JAK2-mutated than in CALR-mutated essential thrombocythemia. Patients with JAK2 (V617F) were older, had a higher hemoglobin level and white blood cell count, and lower platelet count and serum erythropoietin than those with CALR mutation. Hematologic parameters of patients with JAK2-mutated essential thrombocythemia or polycythemia vera were related to the mutant allele burden. While no polycythemic transformation was observed in CALR-mutated patients, the cumulative risk was 29% at 15 years in those with JAK2-mutated essential thrombocythemia. There was no significant difference in myelofibrotic transformation between the 2 subtypes of essential thrombocythemia. Patients with JAK2-mutated essential thrombocythemia and those with polycythemia vera had a similar risk of thrombosis, which was twice that of patients with the CALR mutation. These observations are consistent with the notion that JAK2-mutated essential thrombocythemia and polycythemia vera represent different phenotypes of a single myeloproliferative neoplasm, whereas CALR-mutated essential thrombocythemia is a distinct disease entity.

Somatic mutations of calreticulin in myeloproliferative neoplasms.

BACKGROUND: Approximately 50 to 60% of patients with essential thrombocythemia or primary myelofibrosis carry a mutation in the Janus kinase 2 gene (JAK2), and an additional 5 to 10% have activating mutations in the thrombopoietin receptor gene (MPL). So far, no specific molecular marker has been identified in the remaining 30 to 45% of patients. METHODS: We performed whole-exome sequencing to identify somatically acquired mutations in six patients who had primary myelofibrosis without mutations in JAK2 or MPL. Resequencing of CALR, encoding calreticulin, was then performed in cohorts of patients with myeloid neoplasms. RESULTS: Somatic insertions or deletions in exon 9 of CALR were detected in all patients who underwent whole-exome sequencing. Resequencing in 1107 samples from patients with myeloproliferative neoplasms showed that CALR mutations were absent in polycythemia vera. In essential thrombocythemia and primary myelofibrosis, CALR mutations and JAK2 and MPL mutations were mutually exclusive. Among patients with essential thrombocythemia or primary myelofibrosis with nonmutated JAK2 or MPL, CALR mutations were detected in 67% of those with essential thrombocythemia and 88% of those with primary myelofibrosis. A total of 36 types of insertions or deletions were identified that all cause a frameshift to the same alternative reading frame and generate a novel C-terminal peptide in the mutant calreticulin. Overexpression of the most frequent CALR deletion caused cytokine-independent growth in vitro owing to the activation of signal transducer and activator of transcription 5 (STAT5) by means of an unknown mechanism. Patients with mutated CALR had a lower risk of thrombosis and longer overall survival than patients with mutated JAK2. CONCLUSIONS: Most patients with essential thrombocythemia or primary myelofibrosis that was not associated with a JAK2 or MPL alteration carried a somatic mutation in CALR. The clinical course in these patients was more indolent than that in patients with the JAK2 V617F mutation. (Funded by the MPN Research Foundation and Associazione Italiana per la Ricerca sul Cancro.).

Complex patterns of chromosome 11 aberrations in myeloid malignancies target CBL, MLL, DDB1 and LMO2.

Exome sequencing of primary tumors identifies complex somatic mutation patterns. Assignment of relevance of individual somatic mutations is difficult and poses the next challenge for interpretation of next generation sequencing data. Here we present an approach how exome sequencing in combination with SNP microarray data may identify targets of chromosomal aberrations in myeloid malignancies. The rationale of this approach is that hotspots of chromosomal aberrations might also harbor point mutations in the target genes of deletions, gains or uniparental disomies (UPDs). Chromosome 11 is a frequent target of lesions in myeloid malignancies. Therefore, we studied chromosome 11 in a total of 813 samples from 773 individual patients with different myeloid malignancies by SNP microarrays and complemented the data with exome sequencing in selected cases exhibiting chromosome 11 defects. We found gains, losses and UPDs of chromosome 11 in 52 of the 813 samples (6.4%). Chromosome 11q UPDs frequently associated with mutations of CBL. In one patient the 11qUPD amplified somatic mutations in both CBL and the DNA repair gene DDB1. A duplication within MLL exon 3 was detected in another patient with 11qUPD. We identified several common deleted regions (CDR) on chromosome 11. One of the CDRs associated with de novo acute myeloid leukemia (P=0.013). One patient with a deletion at the LMO2 locus harbored an additional point mutation on the other allele indicating that LMO2 might be a tumor suppressor frequently targeted by 11p deletions. Our chromosome-centered analysis indicates that chromosome 11 contains a number of tumor suppressor genes and that the role of this chromosome in myeloid malignancies is more complex than previously recognized.

Clinical significance of genetic aberrations in secondary acute myeloid leukemia.

The study aimed to identify genetic lesions associated with secondary acute myeloid leukemia (sAML) in comparison with AML arising de novo (dnAML) and assess their impact on patients' overall survival (OS). High-resolution genotyping and loss of heterozygosity mapping was performed on DNA samples from 86 sAML and 117 dnAML patients, using Affymetrix Genome-Wide Human SNP 6.0 arrays. Genes TP53, RUNX1, CBL, IDH1/2, NRAS, NPM1, and FLT3 were analyzed for mutations in all patients. We identified 36 recurrent cytogenetic aberrations (more than five events). Mutations in TP53, 9pUPD, and del7q (targeting CUX1 locus) were significantly associated with sAML, while NPM1 and FLT3 mutations associated with dnAML. Patients with sAML carrying TP53 mutations demonstrated lower 1-year OS rate than those with wild-type TP53 (14.3% ± 9.4% vs. 35.4% ± 7.2%; P = 0.002), while complex karyotype, del7q (CUX1) and del7p (IKZF1) showed no significant effect on OS. Multivariate analysis confirmed that mutant TP53 was the only independent adverse prognostic factor for OS in sAML (hazard ratio 2.67; 95% CI: 1.33-5.37; P = 0.006). Patients with dnAML and complex karyotype carried sAML-associated defects (TP53 defects in 54.5%, deletions targeting FOXP1 and ETV6 loci in 45.4% of the cases). We identified several co-occurring lesions associated with either sAML or dnAML diagnosis. Our data suggest that distinct genetic lesions drive leukemogenesis in sAML. High karyotype complexity of sAML patients does not influence OS. Somatic mutations in TP53 are the only independent adverse prognostic factor in sAML. Patients with dnAML and complex karyotype show genetic features associated with sAML and myeloproliferative neoplasms.

Frequent deletions of JARID2 in leukemic transformation of chronic myeloid malignancies.

Chronic myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS) have an inherent tendency to progress to acute myeloid leukemia (AML). Using high-resolution SNP microarrays, we studied a total of 517 MPN and MDS patients in different disease stages, including 77 AML cases with previous history of MPN (N = 46) or MDS (N = 31). Frequent chromosomal deletions of variable sizes were detected, allowing the mapping of putative tumor suppressor genes involved in the leukemic transformation process. We detected frequent deletions on the short arm of chromosome 6 (del6p). The common deleted region on 6p mapped to a 1.1-Mb region and contained only the JARID2 gene--member of the polycomb repressive complex 2 (PRC2). When we compared the frequency of del6p between chronic and leukemic phase, we observed a strong association of del6p with leukemic transformation (P = 0.0033). Subsequently, analysis of deletion profiles of other PRC2 members revealed frequent losses of genes such as EZH2, AEBP2, and SUZ12; however, the deletions targeting these genes were large. We also identified two patients with homozygous losses of JARID2 and AEBP2. We observed frequent codeletion of AEBP2 and ETV6, and similarly, SUZ12 and NF1. Using next generation exome sequencing of 40 patients, we identified only one somatic mutation in the PRC2 complex member SUZ12. As the frequency of point mutations in PRC2 members was found to be low, deletions were the main type of lesions targeting PRC2 complex members. Our study suggests an essential role of the PRC2 complex in the leukemic transformation of chronic myeloid disorders.

Functional dissection of the TBK1 molecular network.

TANK-binding kinase 1 (TBK1) and inducible IκB-kinase (IKK-i) are central regulators of type-I interferon induction. They are associated with three adaptor proteins called TANK, Sintbad (or TBKBP1) and NAP1 (or TBKBP2, AZI2) whose functional relationship to TBK1 and IKK-i is poorly understood. We performed a systematic affinity purification-mass spectrometry approach to derive a comprehensive TBK1/IKK-i molecular network. The most salient feature of the network is the mutual exclusive interaction of the adaptors with the kinases, suggesting distinct alternative complexes. Immunofluorescence data indicated that the individual adaptors reside in different subcellular locations. TANK, Sintbad and NAP1 competed for binding of TBK1. The binding site for all three adaptors was mapped to the C-terminal coiled-coil 2 region of TBK1. Point mutants that affect binding of individual adaptors were used to reconstitute TBK1/IKK-i-deficient cells and dissect the functional relevance of the individual kinase-adaptor edges within the network. Using a microarray-derived gene expression signature of TBK1 in response virus infection or poly(I∶C) stimulation, we found that TBK1 activation was strictly dependent on the integrity of the TBK1/TANK interaction.

Identification of genomic aberrations associated with disease transformation by means of high-resolution SNP array analysis in patients with myeloproliferative neoplasm.

Myeloproliferative neoplasms (MPN) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These disorders may undergo phenotypic shifts, and may specifically evolve into secondary myelofibrosis (MF) or acute myeloid leukemia (AML). We studied genomic changes associated with these transformations in 29 patients who had serial samples collected in different phases of disease. Genomic DNA from granulocytes, i.e., the myeloproliferative genome, was processed and hybridized to genome-wide human SNP 6.0 arrays. Most patients in chronic phase had chromosomal regions with uniparental disomy (UPD) and/or copy number changes. Disease progression to secondary MF or AML was associated with the acquisition of additional chromosomal aberrations in granulocytes (P = 0.002). A close relationship was observed between aberrations of chromosome 9p (UPD and/or gain) and progression from PV to post-PV MF (P = 0.002). The acquisition of one or more aberrations involving chromosome 5, 7, or 17p was specifically associated with progression to AML (OR 5.9, 95% CI 1.2-27.7, P = 0.006), and significantly affected overall survival (HR 18, 95% CI 1.9-164, P = 0.01). These observations indicate that disease progression from chronic-phase MPN to secondary MF or AML is associated with specific chromosomal aberrations that can be detected by means of high-resolution SNP array analysis of granulocyte DNA.

Genome integrity of myeloproliferative neoplasms in chronic phase and during disease progression.

Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are clonal myeloid disorders with increased production of terminally differentiated cells. The disease course is generally chronic, but some patients show disease progression (secondary myelofibrosis or accelerated phase) and/or leukemic transformation. We investigated chromosomal aberrations in 408 MPN samples using high-resolution single-nucleotide polymorphism microarrays to identify disease-associated somatic lesions. Of 408 samples, 37.5% had a wild-type karyotype and 62.5% harbored at least 1 chromosomal aberration. We identified 25 recurrent aberrations that were found in 3 or more samples. An increased number of chromosomal lesions was significantly associated with patient age, as well as with disease progression and leukemic transformation, but no association was observed with MPN subtypes, Janus kinase 2 (JAK2) mutational status, or disease duration. Aberrations of chromosomes 1q and 9p were positively associated with disease progression to secondary myelofibrosis or accelerated phase. Changes of chromosomes 1q, 7q, 5q, 6p, 7p, 19q, 22q, and 3q were positively associated with post-MPN acute myeloid leukemia. We mapped commonly affected regions to single target genes on chromosomes 3p (forkhead box P1 [FOXP1]), 4q (tet oncogene family member 2 [TET2]), 7p (IKAROS family zinc finger 1 [IKZF1]), 7q (cut-like homeobox 1 [CUX1]), 12p (ets variant 6 [ETV6]), and 21q (runt-related transcription factor 1 [RUNX1]). Our data provide insight into the genetic complexity of MPNs and implicate new genes involved in disease progression.

The role of the JAK2 GGCC haplotype and the TET2 gene in familial myeloproliferative neoplasms.

BACKGROUND: Myeloproliferative neoplasms constitute a group of diverse chronic myeloid malignancies that share pathogenic features such as acquired mutations in the JAK2, TET2, CBL and MPL genes. There are recent reports that a JAK2 gene haplotype (GGCC or 46/1) confers susceptibility to JAK2 mutation-positive myeloproliferative neoplasms. The aim of this study was to examine the role of the JAK2 GGCC haplotype and germline mutations of TET2, CBL and MPL in familial myeloproliferative neoplasms. DESIGN AND METHODS: We investigated patients with familial (n=88) or sporadic (n=684) myeloproliferative neoplasms, and a control population (n=203) from the same demographic area in Italy. Association analysis was performed using tagged single nucleotide polymorphisms (rs10974944 and rs12343867) of the JAK2 haplotype. Sequence analysis of TET2, CBL and MPL was conducted in the 88 patients with familial myeloproliferative neoplasms. RESULTS: Association analysis revealed no difference in haplotype frequency between familial and sporadic cases of myeloproliferative neoplasms (P=0.6529). No germline mutations in TET2, CBL or MPL that segregate with the disease phenotype were identified. As we observed variability in somatic mutations in the affected members of a pedigree with myeloproliferative neoplasms, we postulated that somatic mutagenesis is increased in familial myeloproliferative neoplasms. Accordingly, we compared the incidence of malignant disorders between sporadic and familial patients. Although the overall incidence of malignant disorders did not differ significantly between cases of familial and sporadic myeloproliferative neoplasms, malignancies were more frequent in patients with familial disease aged between 50 to 70 years (P=0.0198) than in patients in the same age range with sporadic myeloproliferative neoplasms. CONCLUSIONS: We conclude that the JAK2 GGCC haplotype and germline mutations of TET2, CBL or MPL do not explain familial clustering of myeloproliferative neoplasms. As we observed an increased frequency of malignant disorders in patients with familial myeloproliferative neoplasms, we hypothesize that the germline genetic lesions that underlie familial clustering of myeloproliferative neoplasms predispose to somatic mutagenesis that is not restricted to myeloid hematopoietic cells but cause an increase in overall carcinogenesis.

A common JAK2 haplotype confers susceptibility to myeloproliferative neoplasms.

Genome-wide association studies have identified a number of new disease susceptibility loci that represent haplotypes defined by numerous SNPs. SNPs within a disease-associated haplotype are thought to influence either the expression of genes or the sequence of the proteins they encode. In a series of investigations of the JAK2 gene in myeloproliferative neoplasms, we uncovered a new property of haplotypes that can explain their disease association. We observed a nonrandom distribution of the somatic JAK2(V617F) oncogenic mutation between two parental alleles of the JAK2 gene. We identified a haplotype that preferentially acquires JAK2(V617F) and confers susceptibility to myeloproliferative neoplasms. One interpretation of our results is that a certain combination of SNPs may render haplotypes differentially susceptible to somatic mutagenesis. Thus, disease susceptibility loci may harbor somatic mutations that have a role in disease pathogenesis.

Influence of child abuse on adult depression: moderation by the corticotropin-releasing hormone receptor gene.

CONTEXT: Genetic inheritance and developmental life stress both contribute to major depressive disorder in adults. Child abuse and trauma alter the endogenous stress response, principally corticotropin-releasing hormone and its downstream effectors, suggesting that a gene x environment interaction at this locus may be important in depression. OBJECTIVE: To examine whether the effects of child abuse on adult depressive symptoms are moderated by genetic polymorphisms within the corticotropin-releasing hormone type 1 receptor (CRHR1) gene. DESIGN: Association study examining gene x environment interactions between genetic polymorphisms at the CRHR1 locus and measures of child abuse on adult depressive symptoms. SETTING: General medical clinics of a large, public, urban hospital and Emory University, Atlanta, Georgia. PARTICIPANTS: The primary participant population was 97.4% African American, of low socioeconomic status, and with high rates of lifetime trauma (n = 422). A supportive independent sample (n = 199) was distinct both ethnically (87.7% Caucasian) and socioeconomically (less impoverished). MAIN OUTCOME MEASURES: Beck Depression Inventory scores and history of major depressive disorder by the Structured Clinical Interview for DSM-IV Axis I Disorders. RESULTS: Fifteen single-nucleotide polymorphisms spanning 57 kilobases of the CRHR1 gene were examined. We found significant gene x environment interactions with multiple individual single-nucleotide polymorphisms (eg, rs110402, P = .008) as well as with a common haplotype spanning intron 1 (P < .001). Specific CRHR1 polymorphisms appeared to moderate the effect of child abuse on the risk for adult depressive symptoms. These protective effects were supported with similar findings in a second independent sample (n = 199). CONCLUSIONS: These data support the corticotropin-releasing hormone hypothesis of depression and suggest that a gene x environment interaction is important for the expression of depressive symptoms in adults with CRHR1 risk or protective alleles who have a history of child abuse.