EGFR mutations are more frequent in well-differentiated than in poor-differentiated lung adenocarcinomas.

Somatic mutations in epidermal growth factor receptor (EGFR) tyrosine kinase domain, particularly deletions in exon 19 and point mutation in exon 21, are associated with clinical outcome in patients with lung adenocarcinoma, suggesting that EGFR mutation would have an important role in clinical decision making. DNA was extracted from the excised specimens of 60 lung adenocarcinoma patients with phenol-chloroform and ethanol precipitation. Exon 19 and 21 were amplified by PCR, and direct sequenced from both sense and antisense directions. EGFR somatic mutations were present in 13 of 60 patients (21.67%), including seven cases of in-frame deletion in exon 19 around codon 746 and six cases of amino acid substitution in exon 21. Exon 21 mutation is more frequent in adenocarcinomas with bronchi-alveolar component than exon 19 deletions. Mutations were more prevalent in well-differentiated adenocarcinomas (9/27, 33.33%) than in moderate to poor-differentiated adenocarcinomas (4/33, 12.12%) (P < 0.05). Adenocarcinomas with bronchi-alveolar components had higher mutation frequency (8/22,36. 36%) than those without bronchi-alveolar components (5/38, 13.16%) (P < 0.05). In this study, female patients had more mutation rate than male patients. This trend was also observed in the patients with pathologic stage I-II compared with stage III-IV, but neither of them was statistically significant. Patients with cisplatin-based adjuvant chemotherapy had no significantly prolonged survival compared with single radical resection. But patients with EGFR mutation had relative longer survival. In conclusion, our study suggest that EGFR mutations may be a valuable prognostic factor for disease free survival of surgically treated lung adenocarcinoma patients independently from adjuvant chemotherapy.

[P2Y purinergic receptor activated PI-3K/Akt signaling pathway in regulation of growth and invasion of prostatic cancer].

OBJECTIVE: To investigate P2Y purinergic receptor activated PI-3K/Akt signaling pathway in the regulation of growth and invasion of prostate cancer in vitro. METHODS: Western blot was used to detect phosphorylation of Akt (a downstream target molecule of PI-3K) by P2Y receptor agonist in 1E8 cells (a highly metastatic subclone derived from PC-3 prostatic cancer cell line). Cell counts, flow cytometry, Matrigel invasion assay, wound healing assay and gelatin zymography were used to detect changes of biological behaviors of 1E8 cells after P2Y receptor activation. RESULTS: AMP-PNP, one non-hydrolysis ATP analogue and P2Y receptor agonist, induced significant phosphorylation of Akt in a time- and dose-dependent manner in IE8 cells. LY294002, a specific inhibitor of PI-3K, effectively blocked Akt phosphorylation induced by AMP-PNP. Continuous exposure to AMP-PNP induced significant growth inhibition of 1E8 cells (inhibition rate at 50.2% at the 8th day), and this inhibition was mainly due to an arrest at S phase of the cell cycle (the S phase fraction of AMP-PNP treated cells was 22.3% higher than that of the control). Application of LY294002 did not reverse the growth inhibition effect of AMP-PNP. Matrigel invasion assay showed that AMP-PNP stimulation increased invasive ability of 1E8 cells, and this effect was effectively blocked by LY294002. No significant changes in the activation of MMP-2 and MMP-9 were detected by gelatin zymography, although wound healing assay showed 21.2% increase in cell migration after AMP-PNP treatment. CONCLUSIONS: PI-3K/Akt signaling pathway participates in P2Y receptor-stimulated prostate cancer invasion by enhancing cell motility, rather than up-regulating MMP-2 and MMP-9 activities. PI-3K signaling pathway plays an important role in prostate cancer proliferation, but is not involved in P2Y receptor mediated growth inhibition.

[Status and clinical implication of c-kit and PDGFRA mutations in 165 cases of gastrointestinal stromal tumor (GIST)].

OBJECTIVE: To investigate the status of c-kit and PDGFRA mutations of GIST in a the large sample of Chinese patients. METHOD: One hundred and sixty-five cases were evaluated for the presence of c-kit and PDGFRA mutations. Exon 9, 11, 13, 17 of c-kit and exon 12, 18 of PDGFRA were analyzed by PCR amplification and direct sequencing. RESULTS: Immunohistochemical demonstrations of KIT (CD117) were seen in 94% of the cases (155/165). Overall, c-kit mutations were identified in 76.1% (118/155) of CD117 positive cases: 67.1% (104/155) involving exon 11, 7.1% (11/155) involving exon 9, 1.3% (2/155) involving exon 13 and 0.6% (1/155) involving exon 17. The c-kit exon 11 mutations were mostly heterogeneous and clustered in the classic "hot spot" at the 5' end of the exon, including in-frame deletion and point mutation. The second "hot spots" were internal tandem duplications (ITD) at the 3' end of the exon, which were associated with female patient, older age, stomach location and low mitotic counts. The exon 9 mutations correlated with a distinct subset of GISTs involving the small bowel of young male patients. A new point mutation of L641P was identified in exon 13. PDGFRA mutations were present in 50% (5/10) of CD117-negative GISTs, all involving exon 18 with the majority of mutations being D842V. One novel in-frame deletion of IMHD mutation at codon 843 - 846 with S847T was identified. GISTs with PDGFRA mutations were often larger tumors arising from the omentum/mesentery of young male patients with high risk of aggressive behavior. CONCLUSIONS: The vast majority of GISTs in this study harbored c-kit and PDGFRA mutations, there were non-random relations between the gene mutation patterns and the locations of GISTs. It appears that Chinese GIST patients have some unique mutation patterns. It is necessary to evaluate the gene mutations status of GISTs to guide target therapy.

[Detection of Mycobacterium tuberculosis DNA in sarcoidosis samples using real-time fluorescence polymerase chain reaction].

OBJECTIVE: To study the role of Mycobacterium tuberculosis in the pathogenesis of sarcoidosis. METHODS: Archival material of 22 patients with a histologic diagnosis of sarcoidosis were retrieved. Real-time fluorescent polymerase chain reaction (PCR) was used to detect DNA fragments of the complex-specific insertion sequence IS6110 of Mycobacterium tuberculosis in formalin-fixed and paraffin-embedded biopsy samples. RESULTS: Among the 22 samples studied, Mycobacterium tuberculosis DNA was detected in 11 cases. The sequence of PCR amplified IS6110 DNA fragments completely matched with the related sequence in Mycobacterium tuberculosis gene. CONCLUSIONS: Mycobacterium tuberculosis DNA is identified in a certain proportion of patients with a clinicopathologic diagnosis of sarcoidosis. Mycobacterium tuberculosis may be an important etiologic agent, at least in some of these patients.

[SHP2 and MKP5 in P2Y purinergic receptor-mediated prostate cancer invasion].

OBJECTIVE: To investigate the effects of protein tyrosine phosphatase-SHP2 and dual-specificity MAPK phosphatase-MKP5 on the activation of MAPKs and cell invasion induced by P2Y purinergic receptor in human prostate cancer cell lines with different metastatic potentials. METHODS: The wide type (-wt) SHP2, mutant type (-cs) SHP2 and wide type (-wt) MKP5 cDNA expression vectors were constructed and stably transfected into 1E8 cells (highly metastatic) and/or 2B4 cells (non-metastatic). The tyrosine phosphorylation of SHP2 was examined by immunoprecipitation. The activation of ERK1/2 and p38 induced by P2Y receptor agonist ATP was analyzed by Western blot with phospho-specific antibodies against the dually phosphorylated, active forms of ERK1/2 and p38. The in-vitro invasive ability through Matrigel was measured by boyden-chamber assay. RESULTS: ATP induced significant SHP2 phosphorylation, which was stronger and lasted longer in 1E8 than in 2B4. SHP2-wt enhanced the ERK1/2 activation induced by ATP in 2B4 cells, while SHP2-cs delayed and decreased this effect in 1E8 cells. Both SHP2-wt and SHP2-cs had no obvious influence on p38 activation. ATP stimulated cell invasion of both 1E8 and 2B4, while transfection of SHP2-wt into 2B4 cells further increased the invasive-stimulating ability of ATP (18.7% increase compared with ATP treatment alone). Transfection of SHP2-cs into 1E8 cells, however, antagonized the invasive-stimulating ability of ATP (40.9% decrease compared with ATP treated group). Up-regulation of MKP5-wt inhibited phosphorylation of p38 by ATP and reduced cell invasion stimulated by ATP (22.4% and 28.7% decrease compared with ATP treated group of 1E8 and 2B4, respectively). CONCLUSIONS: Both SHP2 and MKP5 play some roles in P2Y receptor-mediated activation of MEK/ERK, p38 signaling pathways and prostate cancer invasion. SHP2 positively regulates ERK activation and prostate cancer invasion, whereas MKP5 inhibits the invasion by suppressing p38 activation.

[ERK1/2 and p38 kinases are important regulators in P2Y receptor-mediated prostate cancer invasion].

OBJECTIVE: To explore whether ERK1/2 and p38 pathways mediate P2Y receptor-induced prostate cancer invasion. METHODS: The two subclones from the PC-3 human prostate carcinoma cell line: 1E8 (highly metastatic) and 2B4 (non-metastatic), were cultured and transfected with the plasmid pcDNA3-KA-MEK1 containing the dominant negative mutant of MEK1 (KA-MEK1) and wild type MKP-5 (a dual-specificity phosphatase of p38). P2Y receptor-activated ERK1/2 and p38 kinases were detected using phospho-specific antibodies directed against the dually phosphorylated active forms of these kinases by Western blotting. P2Y receptor agonists ATP and P2Y receptor antagonist suramin were used respectively to observe their effects on the activity of ERK1/2. The roles ERK1/2 and p38 pathways play in P2Y receptor-induced in vitro invasion were detected by in vitro invasion assay. The cells were pre-treated with ATP, SB203580, a p38 inhibitor, and PD98059, a blocker of ERK1/2 pathway, respectively. RESULTS: ATP activated ERK1/2 and p38 kinase time-dependently. Suramin significantly inhibited the activation of ERK1/2 and p38 kinase by ATP. ATP stimulated prostate cancer cell invasion. The stimulated cancer cell invasion was significantly inhibited by pretreatment of the cells with PD98059 or SB203580. Transfected of 1E8 cells with KA-MEK1 or up-regulation of MKP-5 both, while inhibiting phosphorylation of ERK1/2 or p38, significantly reduced the invasion of prostate cancer cells in vitro. CONCLUSION: P2Y receptor-induced prostate cancer cell invasion is mainly regulated through ERK1/2 and p38 pathways.

In vitro study of HIF-1 activation and VEGF release by bFGF in the T47D breast cancer cell line under normoxic conditions: involvement of PI-3K/Akt and MEK1/ERK pathways.

Hypoxia-inducible factor (HIF) is critical in the modulation of tumour angiogenesis in response to hypoxia. In the present study, the mechanisms underlying basic fibroblast growth factor (bFGF)-induced activation of HIF-1 and the subsequent release of vascular endothelial growth factor (VEGF) in a human breast cancer cell line (T47D) under normoxic conditions were explored. The data show that HIF-1alpha expression is induced by bFGF in a dose- and time-dependent fashion, while increased HIF-1alpha protein expression and transactivity of HIF-1 are due to the phosphorylation of Akt by bFGF, as indicated by application of the phosphatidylinositol 3-kinase (PI-3K) inhibitor LY294002. The data also show that the MEK1 (mitogen-activated protein kinase kinase-1)/ERK (extracellular signal-regulated kinase) pathway is only involved in bFGF-induced transactivity of HIF-1, but not HIF-1alpha expression, indicating roles for both the PI-3K/Akt and the MEK1/ERK pathways in bFGF activity. In addition, the translation inhibitor cycloheximide confirmed that bFGF-induced HIF-1alpha protein expression was due to de novo protein synthesis. In contrast, p38 was not required for the expression of HIF-1alpha or HIF-1 transactivity, although significant phosphorylation of p38 was observed after bFGF treatment. Treatment of the cells with bFGF increased the amount of VEGF release, and this could be suppressed by either PD98059 or LY294002, suggesting the presence of a HIF-1alpha-dependent pathway for bFGF-induced VEGF production. In conclusion, the PI-3K/Akt and MEK1/ERK pathways, in a potentially independent and co-operative fashion, can modulate HIF-1 activation by bFGF. Further studies will pinpoint whether HIF-1 is the transcriptional factor responsible for the increased VEGF production following bFGF treatment of breast tumour cells.

ERK1/2 and p38 pathways are required for P2Y receptor-mediated prostate cancer invasion.

The G protein-coupled P2Y purinoceptors have wide physiological functions, but their role(s) in tumor progression remain unclear. Here, we report that stimulation of P2Y receptors enhances prostate cancer cell invasion in two human prostate carcinoma cell lines, which is mediated by ERK1/2 and p38 signaling pathways. P2Y agonists stimulated prostate cancer cell invasion, and increased the activities of ERK1/2 and p38 protein kinases. The stimulated cancer cell invasion was inhibited by the presence of MEK1 inhibitor PD98059 or p38 inhibitor SB203580. Expression of dominant-negative mutant of MEK1 (KA-MEK1), or up-regulation of MKP-5 (a dual-specificity phosphatase of p38), both reduced the invasion of cultured prostate cancer cells. These results suggest that P2Y receptors and their down-stream ERK1/2 and p38 protein kinases are important regulators promoting prostate cancer invasion.

[Diagnosis of lymph node micrometastases in human lung carcinoma: determination of p53 gene mutations by polymerase chain reaction-temperature gradient gel electrophoresis (PCR-TGGE)].

BACKGROUND & OBJECTIVE: Metastasis is one of the most important factors in determining the prognosis of lung cancer patients. However, it is difficult to determine single cancer cell in lymph nodes by routine methods. This study was designed to investigate a sensitive method for detecting lymph node micrometastases in human lung carcinomas. METHODS: Mutation detection for p53 gene (exon 5-8) was performed in 39 cases of primary lung carcinomas and 110 corresponding lymph nodes (LNS) by PCR-TGGE method. Serial sectioning was performed to confirm micrometastases in some of these samples. RESULTS: p53 mutations were found in 23 of 39 cases with primary lung cancer. Forty LNSs showed p53 mutation in 67 corresponding LNSs. They were located at the same exon as their primary tumors. Only twenty-six LNSs were detected metastases by routine histopathology. Forty-three LNSs from sixteen cases of primary tumor without p53 mutation and ten LNSs from the patients without tumor disease did not have any p53 mutations. By PCR-TGGE assay p53 gene mutations were determined in fourteen LNSs without histopathological evidence of metastasis. Micrometastases were found in four of the serially sectioned cases. CONCLUSION: Mutation detection for p53 gene (exon 5-8) showed lymph node micrometastases in patients with lung carcinoma. It may be used as a complement for the routine histopathology.

[Effects of P2Y receptor activation on prostatic cancer cells requiring ERK1/2 or p38 cascade].

OBJECTIVE: To determine the role of extracellular signal-regulated kinase (ERK1/2) and p38 cascades in P2Y receptor-evoked effects on prostatic cancer cells. METHODS: Highly metastatic prostatic cancer cells 1E8 were transfected with dominant-negative MAPK kinase 1 (KA-MEK1). The activation of ERK1/2 was determined by Western blot technique. The role of ERK1/2 and p38 cascades in P2Y receptor-evoked effects on in vitro growth, colony formation and in vitro invasion was detected by cell count, soft agar colony formation assay and in vitro invasion assay. The effect of ATP on apoptosis was detected by flow cytometry. RESULTS: ERK1/2 activity in 1E8-KA-MEK1 transfectants was significantly suppressed by dominant-negative MEK1 transfection. After culture of 6 days, 1E8-KA-MEK1 transfectants exhibited a growth inhibition of 71% as compared with 1E8-pcDNA3 control. Moreover, after continuous treatment with 100 micro mol/L ATP for 6 days, the growth of 1E8-KA-MEK1 transfectants was further inhibited by an additional 17.2%. Pretreatment with 10 micro mol/L p38 inhibitor SB203580 antagonized the effect of ATP-induced additional growth inhibition, suggesting that ERK1/2 and p38 pathways play an important role in ATP-induced growth inhibition. In soft agar assay, 1E8-KA-MEK1 transfectants formed smaller colonies and exhibited a 75% decrease in colony formation (as compared with control). Further treatment with ATP or SB203580 plus ATP did not show significant effect on colony formation of 1E8-KA-MEK1 cells, implying a potential role of ERK1/2, instead of p38, in P2Y receptor-mediated inhibitory effect on colony formation. In in vitro invasion assay, 1E8-KA-MEK1 cells showed a 41% decrease in passing through matrigel-coated membranes, as compared with control. Treatment with ATP could restore their invasive ability, and this effect by ATP could be blocked by pretreatment with SB203580, indicating the involvement of both ERK1/2 and p38 pathways in invasive ability of prostatic cancer cells. CONCLUSIONS: The effects of ATP on in vitro growth, invasion and colony formation of prostatic cancer cells depend on the status of P2Y receptor activation by different treatment protocols. Continuous activation of P2Y receptor results in growth inhibition and transient activation of P2Y receptor stimulates in vitro invasion of prostatic cancer cells. Both ERK1/2 and p38 pathways are responsible for these effects; but only the ERK1/2 pathway is involved in regulation of colony formation of prostatic cancer cells.

[Activation of HIF-1 by bFGF in breast cancer: role of PI-3K and MEK1/ERK pathways].

OBJECTIVE: To explore the mechanism of basic fibroblast growth factor (bFGF)-mediated hypoxia inducible factor (HIF-1) activation and the down-stream signaling pathways involved. METHODS: Human breast cancer cells of the line T47D were cultured and lysed to extract the total protein in the supernatant. The amounts of extracellular signal kinase 1/2 (ERK1/2), Akt, p38, and beta-tubulin were measured. T47D cells were inoculated into a 24-well plate, co-transfected with luciferase vector OB-HRE containing HIF-1 functional sequence (HRE) and pRL-SV40 (as inner marker), pretreated with SU5402, inhibitor of FGFR1, SB203580, inhibitors of PI-3K, PD98059, inhibitors of MEK1, or LY294002, inhibitors of p38, treated with basic fibroblast growth factor (bFGF), and then lysed. The amounts of ERK1/2, Akt, p38, and beta-tubulin were measured. Western blotting was used to detect the HIF-1alpha level in total protein. Dual luciferase assay was used to analyze the transactivity of HIF-1. The firefly/renilla luciferase ratio was measured to access the transcription activity of HIF-1. Western blotting was used to detect the expression of HIF-1alpha protein and phosphorylated Akt, ERK1/2 and p38 in whole cell extract. RESULTS: After the addition of bFGF Western blotting showed that the and phosphorylation of Akt, ERK1/2 and p38 in the T47D cells were increased time- and dose-dependent manner, and dual luciferase assay showed that the fluorescent intensity was increased, signifying the increase of expression of HIF-1alpha protein. Ten minutes after the addition of CHX the expression of HIF-1alpha protein began to be decreased and ceased 90 minutes after. SU5402 remarkably dose-dependently blocked the bFGF-induced phosphorylation of ERK1/2, Akt and p38. 15 micromol/L LY294002 completely blocked the bFGF-induced phosphorylation of Akt. 5 micromol/L PD98059 blocked 80% of the bFGF-induced phosphorylation of ERK1/2. 10 approximately 20 micromol/L SB203580 basically blocked the bFGF-induced phosphorylation of p38. SU5402 and LY294002 100% inhibited the bFGF-induced expression of HIF-1alpha protein. However, PD98059 and SB203580 did not significantly influence the expression of HIF-1alpha protein induced by bFGF. Luciferase assay showed that SU5402 and PD98059 inhibited the bFGF-induced transcription activity of HIF-1 by 94.8% and 81.7% respectively. LY294002 not only completely inhibited the bFGF-induced transcription activity of HIF-1 but also inhibited the basic transcription of HIF-1, and SB203580 did not significantly influence the transcription activity of HIF-1. CONCLUSION: bFGF activates HIF-1 via the PI-3K/Akt and MEK1/ERK pathways that co-operatively and differentially regulate this process with PI-3K/Akt pathway playing a more important role.

[Mechanism of the mitogen-activated protein kinase phosphatase-5 regulating the growth and invasion of a human prostate cancer cell line].

OBJECTIVE: To investigate the effects of mitogen-activated protein kinase phosphatase-5 (MKP5) on the biological behaviors of cell and the activation of mitogen-activated protein kinase (MAPK) induced by P2Y purinergic receptor agonist ATP in the prostate cancer cell line 1E8. METHODS: 1E8 cells were cultured. The recombinant plasmid pcDL-SRalpha296-MKP5 containing the human wild type MKP5 cDNA and blank vector pcDL-SRalpha were co-transfected with pcDNA3 vector plasmid into the 1E8 cells respectively to get strong expression clones. RT-PCR was used to detect the expression of MKP5 mRNA. ATP, MEK inhibitor PD 98059, and p38 inhibitor SB 203580 were added into the culture. Then the total protein was extracted, SDS-PAGE and Western blotting were used to detect the activation of p38 and ERK1/2 induced by ATP with phosphospecific antibodies directed against the dually phosphorylated, active forms of p38 and ERK1/2. The in vitro growth curve was drawn, soft agar colony formation test was made, and Matrigel membrane-penetrating experiment was made to test the invasion ability of 1E8 cells. RESULTS: The activity of p38 and that of ERK1/2 of the 1E8 cells untreated by ATP were almost undetected. ATP time-dependently stimulated the activities of ERK1/2 and p38 kinases, inhibited the in vitro growth and colony formation on soft agar, and promoted the in vitro invasion of 1E8 cells. MKP5-transfection effectively inhibited the p38 activity induced by ATP and blocked the effects by ATP stimulation on 1E8 cells. The activity of p38 kinase was significantly decreased both in the control and MKP5 transfected cells that were pretreated with SB203580 and then with ATP with an inhibition rates of 83.14% and 58.00% (P < 0.001 and P = 0.003). The growth of cells transfected with MKP5 was significantly inhibited (P < 0.001) and further inhibited by addition of ATP. The inhibition of growth of MKP5-transfected cells by ATP could be partially reversed by pretreatment of PD98059 (P < 0.05). The number of cells transfected with MKP5 that penetrated the membrane was significantly less than that of the control cells (P = 0.000 9). ATP increased the penetrating ability of different cells (all P < 0.01), and this action was partially inhibited by MKP5 transfection and addition of SB203580 (P < 0.001), but not by the addition of PD98059. ATP treatment decreased the colony formation on soft agar of different cells, especially of the MKP5 transfected cells (P < 0.001). Such action was partially reversed by SB203580 and PD98059. CONCLUSION: The p38 and ERK1/2 pathways exert different effects on the in vitro growth, invasion and colony formation of 1E8 prostate cancer cells related to ATP. The p38 pathway may be more important in the invasive capability of 1E8 cells. MKP5 plays an important role in the regulation of p38 action.

[Gene detection of severe acute respiratory syndrome-related coronavirus].

OBJECTIVE: To develop a newly real-time RT-polymerase chain reaction assay for severe acute respiratory syndrome (SARS) related coronavirus in human whole blood. METHODS: A pair of primers and a probe (molecular beacon) had been designed that were specific for the recognition of a highly conservative region between 15 301 and 15 480 of the SARS-related coronavirus polymerase gene sequences obtained from GenBank (G130027616). RESULTS: In the real-time RT-PCR assay, the extent of SARS related coronavirus amplification was measured in terms of the increase in fluorescence during the amplification process. The 145 bp fragment of PCR product was further confirmed by conventional PCR assay and proved by DNA sequencing to be identical to the target sequence to which the probe was hybridized. CONCLUSION: This assay has a broad application for clinical diagnosis and surveillance investigation.

[A novel Krit-1 mutation in Han family with cerebral cavernous malformation].

OBJECTIVE: To detect the mutations of Krit-1 gene that cause familial cerebral cavernous malformation (CCM) in the Han ethnic origin. METHODS: The subjects were hospitalized in the Department of Neurosurgery, Tiantan Hospital affiliated to Capital University of Medical Sciences. Two families (A and B) and 8 apparently sporadic individuals affected with CCM were screened for mutations of Krit-1 gene. Members of the family CCM have a wide range in age of onset with seizures, headaches and skin lesions. The gene was screened by PCR amplification of 16 exons and mutation was detected by direct sequencing. RESULTS: In family A samples, analysis of the Krit-1 gene revealed a new point mutation in exon 14 [a heterozygous C to G transition at nucleotide 1 289 (counting from the start codon or nt 2 308 counting from the first nt of the mRNA, aligned according to Gene Bank AF388384)] which predicts the substitution of a premature termination codon for Serine at codon 430 (S430X), belonging a nonsense point mutation. No mutation was identified in one of family A members as well as in any of the sporadic individuals with the exception of a single nucleotide polymorphism. CONCLUSIONS: Report the first family in the Han with CCM having a novel mutation in the CCM1 gene on the continent of Asia. The newly identified mutation creates a premature termination codon and is predicted to produce a truncated Krev1 interaction-trapped 1 protein, KRIT1. This result allows efficient presymptomatic molecular diagnosis.