The first mutations in the MYH gene reported in Moroccan colon cancer patients

Background

Biallelic germline mutations in the MYH gene cause MYH-associated polyposis (MAP) disease, an autosomal recessive form of inherited colorectal cancer. People with MAP tend to develop attenuated multiple adenomatous colon polyps during their lifetime and will have an increased risk of colorectal cancer. Contrary to familial adenomatous polyposis, the number of adenomas is often lower in MAP (from 5 to 100), and even some patients have recently been reported with no identified adenomas.There have been many investigations into MAP that have been conducted in many different countries. Currently there is limited data on MAP in Morocco, and it is reasonable to think, that the prevalence of this form of genetic predisposition is as high as other autosomal recessive genetic diseases found in countries with high rates of consanguinity.The aim of this study is to examine the frequency of MYH mutations in colorectal cancer and/or attenuated polyposis in Moroccan patients.

Patients and methods

The study population consisted of 62 patients; 52 with colorectal cancer, three of them had attenuated polyposis (2 to 99 adenomatous polyps). 10 other patients were referred to our department for polyposis without colorectal cancer.We carried out DNA analysis in 62 patients to screen for the three recurrent mutations c.494A > G (p.Tyr165Cys), c.1145 G > A (p.Gly382Asp) and c.1185_1186dup, p.Glu396GlyfsX43, whereas 40 subjects were screened for germline MYH mutations in the whole coding sequence of the MYH gene by direct DNA sequencing. All these 40 patients, except two, had colorectal cancer without polyposis.

Results

Three patients with colorectal cancer and attenuated polyposis carried biallelic mutations in the MUTYH gene one with the c.494 A > G mutation, one with the c.1105delC mutation, one with the c.1145 G > A mutation. One patient with 25 adenomas without colorectal cancer carried the c.1145 G > A mutation at a homozygote state and one patient with 3 polyps was heterozygote for the mutation c.1145 G > A. No biallelic mutations of MYH gene were detected in colorectal cancer patients and in patients with small number (< 5) of polyps without colorectal cancer.

Conclusion

We report the first biallelic MYH mutations in four Moroccan patients with clinical criteria of MAP; three of them had colorectal cancer with attenuated polyposis. No MYH mutations were found in colorectal patients without polyposis.Despite the relatively small sample size of the current study, our findings suggest that the MAP is not a frequent cause of colon cancer in Morocco as we had expected, and the molecular analysis of MYH gene should be restricted to patients displaying the classical phenotype of MAP.     

Effectiveness of human mesenchymal stem cells derived from bone marrow cryopreserved for 23-25 years

Objective

To evaluate long-term cryopreserved human bone marrow cells (BMCs) as a source of functional mesenchymal stem cells (MSCs).

Methods

Samples of human BMCs that were cryopreserved for 23–25 years (n = 20) were thawed to obtain an initial culture and a primary culture (P₀) that was propagated through five passages (P₁–P₅) to obtain MSCs. Freshly collected human bone marrow samples (n = 20) were used as controls for comparison of efficiency of recovery and growth characteristics of MSCs. P₃ cultures were tested for their capacity to differentiate into osteoblasts, adipocytes, and neuronal cells. Appropriate staining, immunohistochemical and biochemical methods were employed to ascertain cell type identities at different stages of culturing.

Results

In the initial culture, the cell adherence rate of the cryopreserved cells was significantly lower than that of controls (19.7% vs. 38.2%, p < 0.05) while the relative rate of recovery of MSCs was only 48.5 ± 8.6% in P₀. At the end of P₃, fibroblast-like cells accounted for about 95% of cells in both cryopreserved and control groups (p > 0.05). These cells were positive for essential MSC surface molecules (CD90, CD105, CD166, CD44, CD29, CD71, CD73) and negative for haematopoietic and endothelial cell markers (CD45, CD34, HLA-DR). The cell growth and cell cycle patterns were similar for both groups. MSCs at P₃ from both groups had similar capacities to differentiate in vitro into osteoblasts, adipocytes, and neuronal cells.

Conclusion

Using the methods described here, long-term (23–25 years) cryopreserved human BMCs can be successfully cultivated to obtain MSCs that have good differentiation capabilities.     

RASSF1A Ala133Ser polymorphism is associated with increased susceptibility to hepatocellular carcinoma in a Turkish population

Aim

The tumor suppressor gene Ras association domain family 1 isoform A (RASSF1A) regulates cell cycle regulation, apoptosis and microtubule stability and is inactivated by promoter hypermethylation at a high frequency in hepatocellular carcinoma (HCC). A guanine (G)/thymine (T) common single nucleotide polymorphism (SNP) at first position of codon 133 in RASSF1A gene determines an alanine (Ala) to serine (Ser) (Ala133Ser) amino acidic substitution which may alter cancer risk by influencing the function of RASSF1A protein.

Methods

To determine the association of the RASSF1A Ala133Ser polymorphism with the risk of HCC development in a Turkish population, a hospital-based case–control study was designed consisting of 236 subjects with HCC and 236 cancer-free control subjects matched for age, gender, smoking and alcohol status. The genotype frequency of the RASSF1A Ala133Ser polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay.

Results

Allele and genotype associations of RASSF1A Ala133Ser polymorphism with HCC susceptibility were observed in comparisons between the patient and control samples (P < 0.001). Risk of HCC development in this Turkish population was significantly increased in carriers of the Ser133 variant allele of Ala133Ser polymorphism (Ala/Ser and Ser/Ser genotypes) when compared with homozygote Ala/Ala genotype (OR = 5.47, 95% CI = 3.63–8.25, P = 0.001).

Conclusion

Because our results suggest for the first time that the Ser133 allele of RASSF1A Ala133Ser polymorphism may be a genetic susceptibility factor for HCC in the Turkish population, further independent studies are required to validate our findings in a larger series, as well as in patients of different ethnic origins.     

Genetic structure of South Australian Pyrenophora teres populations as revealed by microsatellite analyses

The aim of this study was to determine the genetic structure of South Australian field populations of the barley net blotch pathogens, Pyrenophora teres f. sp. teres (PTT) and P. teres f. sp. maculata (PTM), using microsatellite DNA markers. Three PTT populations (76 isolates total) and two PTM populations (43 isolates total) were sampled from separate fields during a single growing season. The results showed that of the 20 microsatellite loci examined, 17 (85 %) were polymorphic within the PTT and PTM populations. In total, 120 distinct alleles were identified of which only 11 (9 %) were shared between the two population types. Nei’s measure of gene diversity across the PTT and PTM populations was similar at 0.38 and 0.40, respectively, and also much higher than previously reported from studies in which other types of molecular markers were used. The coefficient of genetic differentiation among both populations was the same (G_ST = 0.03) and the low and insignificant estimates of F_ST, as indicated by θ, between populations of the same type (PTT: θ < 0.008, PTM: θ = 0.014) indicated that isolates sampled from different areas within the same field were genetically similar. In contrast, high and significant genetic differentiation was observed among and between populations of different type (G_ST = 0.42, θ > 0.567). The high number of unique multilocus haplotypes observed within the PTT (84 %) and PTM (100 %) populations, combined with a 1:1 distribution of both mating types, suggested that sexual reproduction was predominant among these populations. However, tests for multilocus associations showed that both PTT and PTM populations were in significant linkage disequilibrium. Although the levels of disequilibrium were low, an asexual reproductive component could not be excluded.     

Laccase activity and putative laccase genes in marine-derived basidiomycetes

Studies of laccases from marine-derived fungi are limited. In the present work, putative laccase genes from three marine-derived basidiomycetes and their laccase activities were evaluated. High amounts of laccase were produced by the fungal strains Marasmiellus sp. CBMAI 1062 (971.2 U L⁻¹) and Peniophora sp. CBMAI 1063 (709.03 U L⁻¹) when grown for 21 d at 28 °C in MA2ASW medium prepared with artificial seawater. Marine-derived basidiomycetes produced multiple distinct laccase sequences of about 200 bp with 73–90 % similarity to terrestrial basidiomycete laccases. Marasmiellus sp. CBMAI 1062 and Tinctoporellus sp. CBMAI 1061 showed the greatest laccase gene diversity with three and four distinct putative laccase sequences, respectively. This is the first report of laccase genes from marine-derived fungi, and our results revealed new putative laccases produced by three basidiomycetes.     

Efficient shoots regeneration and genetic transformation of Bacopa monniera

Bacopa monniera is an important source of metabolites with pharmaceutical value. It has been regarded as a valuable medicinal plant and its entire commercial requirement is met from wild natural population. Recently, metabolic engineering has emerged as an important solution for sustained supply of assured and quality raw material for the production of active principles. Present report describes efficient in vitro multiplication and transformation method for genetic manipulation of this species. MS medium supplemented with 2 mgl⁻¹ BA and 0.2 mgl⁻¹ IAA was found optimum for maximum shoot regeneration (98.33 %) from in vitro leaves with 2–3 longitudinal cuts. Agrobacterium tumefaciens-mediated transformation method was used for generating transgenic B. monniera plants. Putative transformants were confirmed by GUS assay and PCR based confirmation of hptII gene. DNA blot analysis showed single copy insertion of transgene cassette. An average of 87.5 % of the regenerated shoots were found PCR positive for hptII gene and GUS activity was detected in leaves of transgenic shoots at a frequency of 82.5 % The efficient multiple shoots regeneration system described herein may help in mass production of B. monniera plant. Also, the high frequency transformation protocol described here can be used for genetic engineering of B. monniera for enhancement of its pharmaceutically important metabolites.     

Characterization of an extracellular laccase, PbLac1, purified from Polyporus brumalis

Polyporus brumalis (strain ibrc05015) secreted high amounts of laccases (Lacs) in liquid medium. With 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) as a substrate, Lac activity was 7.72 U ml⁻¹ and this strain secreted a maximum 0.23 mg ml⁻¹ of total protein. The enzyme, PbLac1 was purified to homogeneity using hydrophobic and anion-exchange chromatography. The purified PbLac1 had a molecular mass of 63.4 kDa as determined by polyacrylamide-gel electrophoresis. PbLac1 oxidized a wide range of substrates such as 3,4-dihydroxy l-phenylalanine (l-DOPA) and catechol, but not tysorine. The activity of PbLac1 was increased by addition of 10.0 mM Cu²⁺. PbLac1 could decolorize several industrial dyes, such as Remazol Brilliant Blue R known as model dyes of environmental xenobiotics. In addition, PbLac1 decolorized a wide range of substrates, such as the carcinogen, Poly R-478, in the presence of violuric acid as mediator. The E^° value of PbLac1 was 0.80 V ± 0.01 versus normal hydrogen electrode, which is a very high redox potential compared to those of other basidiomycetous Lacs. These results suggest the potential utility of PbLac1 for industrial applications.     

A functional germline variant in the P53 polyadenylation signal and risk of esophageal squamous cell carcinoma

Aim

P53 plays a critical role in the maintenance of genomic stability as well as the control of cell growth and apoptosis. Recently, an uncommon P53 genetic variant (rs78378222) was reported to be significantly associated with multiple cancers in Caucasians in a genome-wide association study. rs78378222 locates in the 3′-untranslated region of the P53 gene, and this A-to-C polymorphism results in changes of the AATAAA polyadenylation signal to AATACA, which leads to impaired 3′-end processing of P53 mRNA and decreased P53 expression.

Methods

We evaluated the association between this polymorphism and esophageal squamous cell carcinoma (ESCC) risk in a case–control cohort consisting of 405 ESCC patients and 810 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression.

Results

We did observe this polymorphism with low minor allele frequency in Chinese Han population. Additionally, significantly increased ESCC risk was associated with P53 rs78378222 A > C polymorphism. Compared with rs78378222AA carriers, the OR of developing ESCC for AC carriers was 3.22 (95% CI = 1.71 − 6.33, P = 1.34 × 10^− 4).

Conclusion

These results suggest that this functional uncommon P53 rs78378222 variant is associated with ESCC risk in the current Han Chinese population.     

Reduction of chronic graft injury with a new HTK-based preservation solution in a murine heart transplantation model

Objective

Aim of this study was to evaluate a new histidine-tryptophan-ketoglutarate (HTK)-based preservation solution on chronic isograft injury in comparison to traditional HTK solution.

Methods

Hearts of C57BL/6J (H-2b) mice were stored for 15 h in 0–4 °C cold preservation solution and then transplanted heterotopically into C57BL/6J (H-2b) mice. Three groups were evaluated: HTK, the base solution of a new preservation solution and hearts without cold ischemia (control). Time to restoration of heartbeat was measured (re-beating time). Strength of the heartbeat was palpated daily and scored on a 4-level scale (palpation score). Animals were sacrificed after 60 days of observation (24 h for TGF-β expression). The transplanted hearts were evaluated histologically for myocardial damage, vasculopathy and interstitial fibrosis. TGF-β expression was assessed immunohistologically. All investigators were blinded to the groups. ANOVA and LSD post hoc test were used for statistical analysis.

Results

The re-beating time was significantly shorter in hearts stored in the new solution (10.3 ± 2.6 min vs. HTK 14.2 ± 4.1 min; p < 0.05). The palpation score was significantly higher in hearts stored in the new solution (2.3 ± 0.4 vs. HTK 1.6 ± 0.5; p < 0.01). Hearts stored in the new solution showed a lower myocardial injury score (1.8 ± 0.2 vs. HTK 2.2 ± 0.7), less interstitial fibrosis (4.8 ± 1.9% vs. HTK 8.5 ± 3.8%, p < 0.05), less vasculopathy (14.7 ± 6.9% vs. 22.0 ± 23.2%; p = 0.06) and lower TGF-β1-expression (6.6 ± 1.4% vs. HTK 12.0 ± 4.6%).

Conclusion

The new HTK-based solution reduces the chronic isograft injury. This protective effect is likely achieved through several modifications and supplements into the new solution like N-acetyl-l-histidine, glycine, alanine, arginine and sucrose.     

Samia cynthia versus Bombyx mori: comparative gene mapping between a species with a low-number karyotype and the model species of Lepidoptera

We performed gene-based comparative FISH mapping between a wild silkmoth, Samia cynthia ssp. with a low number of chromosomes (2n = 25-28) and the model species, Bombyx mori (2n = 56), in order to identify the genomic components that make up the chromosomes in a low-number karyotype. Mapping of 64 fosmid probes containing orthologs of B. mori genes revealed that the homologues of either two or four B. mori chromosomes constitute the S. c. ricini (Vietnam population, 2n = 27??/28??, Z0/ZZ) autosomes. Where tested, even the gene order was conserved between S. c. ricini and B. mori. This was also true for the originally autosomal parts of the neo-sex chromosomes in S. c. walkeri (Sapporo population, 2n = 26??/26??, neo-Wneo-Z/neo-Zneo-Z) and S. cynthia subsp. indet. (Nagano population, 2n = 25??/26??, neo-WZ₁Z₂/Z₁Z₁Z₂Z₂). The results are evidence for an internal stability of lepidopteran chromosomes even when all autosomes had undergone fusion processes to form a low-number karyotype.     

Oceanicella actignis gen. nov., sp. nov., a halophilic slightly thermophilic member of the Alphaproteobacteria

Two isolates, designated PRQ-67^T and PRQ-68, with an optimum growth temperature of about 50 °C, growth range in medium containing between 1 and 9% NaCl and an optimum pH for growth between 7.5 and 8.0, were recovered from a shallow marine hot spring on a beach, Praia do Fogo, at Ribeira Quente, on the Island of São Miguel in the Azores. Comparisons of 16S rRNA gene sequences show these strains to be most closely related (93.1–94.7% similarity) to species of the genus Amaricoccus, within the family Rhodobacteraceae. Strains are non-pigmented and form non-motile pleomorphic cells that stain Gram-negative, are aerobic, oxidase and catalase positive. The major fatty acids are C_18:1ω7c and C_18:1ω7c 11-methyl. Ubiquinone 10 is the major respiratory quinone. Major polar lipids are phosphatidylcholine, phosphatidylglycerol and one aminolipid. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics we describe a new species of a novel genus represented by strain PRQ-67^T (=DSM 22673^T = LMG 25334^T) for which we propose the name Oceanicella actignis.     

A rapid infection assay for Armillaria and real-time PCR quantitation of the fungal biomass in planta

Slow and unreliable infection in the greenhouse has been a barrier to research on Armillaria root disease. The existing infection assay takes 7–18 months for detectable infection, during which time the inoculum often dies, resulting in unequal challenge among plants. Because symptom expression and mortality are rare, presence or absence of infection, determined by culturing, is the only datum derived from the existing infection assay. This limits both routine comparisons of strain virulence and complex investigations of pathogenesis, neither of which have been done for Armillaria mellea. We tested a new infection assay, in which grape rootstocks growing in tissue culture medium are inoculated, and compared to rootstocks previously characterized from the existing infection assay as tolerant (Freedom) or susceptible (3309C). Culture media of 25 plants per rootstock was inoculated and five plants per rootstock were harvested 0, 2, 4, 6, and 8 weeks postinoculation; the experiment was completed twice. Confocal microscopy and quantitative PCR (Q-PCR) were used to quantify infection. Roots were treated with WGA-AlexaFluor488, hyphae and roots were scanned on green and red channels on a confocal microscope, and percent root colonization was quantified. A fungal gene (EF1α) was determined to have a single copy in A. mellea, and both EF1α and a single-copy grape gene (UFGT) were amplified by Q-PCR; fungal DNA: plant DNA served as a measure of fungal biomass. Armillaria was detected by culture, microscopy, and Q-PCR starting 2 weeks postinoculation from all inoculated plants, demonstrating that the new infection assay is rapid and plants do not escape infection. Our findings of higher percent root colonization (as measured by microscopy) of 3309C than Freedom at all harvests (P < 0.0001), consistently higher fungal biomass (as measured by Q-PCR) of 3309 than Freedom, and a significant positive correlation between percent root colonization and fungal biomass (P = 0.01) suggests that the quantitative methods of our new assay give similar results to the qualitative method of the existing infection assay.     

Association study of AGER gene polymorphism and hypertension in Han Chinese population

Background

Advanced glycation end products (AGEs) are produced by non-enzymatic glycation or glycoxidation of proteins, lipids and nucleic acids. The bond of AGEs and the receptor of AGE (AGER) in a pro-oxidant environment could induce immune and inflammation reaction involved in progress of microvascular disease. Accumulated evidence warrant further study on AGE–AGER pathway and genetic susceptibility to hypertension (HT).

Methods

We designed a two-stage association study to evaluate the association of AGER polymorphism and HT. In stage 1, seven tagSNPs were tested in 524 cases and 531 controls and the significant SNPs (P < 0.05) would enter into stage 2 including 807 cases and 869 controls. Furthermore, joint analysis was performed for all 2731 subjects including 1331 cases and 1400 controls, and meta-analysis was applied to evaluate combined estimations from the subgroups of stage 1 and stage 2.

Results

In stage 1, rs204994 had significant association with HT (P < 0.05) and enter stage 2. Neither joint analysis nor meta-analysis found statistical association of rs204994 with HT after adjusted for the covariates in the whole population. However, further stratification analysis found that rs204994 was significantly associated with HT in < 50 years and ≥ 50 years groups, ORs (95%CI) of dominant model were 1.623 (1.054–2.500) and 0.721 (0.546–0.952) respectively. No significant correlation was found between blood pressure and the polymorphisms of rs204994.

Conclusions

Our data suggests that age might modulate the genetic effects of variation of rs204994 in AGER on HT and further replications in other populations and functional studies should be warranted.     

Role of the RAD51 G172T polymorphism in the clinical outcome of cervical cancer patients under concomitant chemoradiotherapy

Introduction

Cervical cancer is one of the most common cancers diagnosed in women worldwide. Mammalian cells are constantly exposed to a wide variety of genotoxic agents from both endogenous and exogenous sources. The RAD51 protein is required for meiotic and mitotic recombination and plays a central role in homology-dependent recombinational repair of double-strand breaks (DSBs). Given the functional relevance of the DNA repair system on carcinogenesis, potential associations between genetic polymorphisms of DNA repair genes, cancer risk and response to therapy have been intensively evaluated. This is the first study evaluating the role of the RAD51 G172T genetic variants in cancer prognosis and clinical outcome of cervical cancer patients.

Material and methods

We analyzed RAD51 G172T polymorphism genotypes in cervical cancer patients who underwent a platinum-based chemotherapy in combination with radiotherapy. Genotyping was performed by Taqman™ Allelic Discrimination methodology.

Results and discussion

Concerning the overall survival rates found using Kaplan–Meier method and Log Rank Test, we observed that the mean survival rates were statistically different according to the patients RAD51 genotypes. The group of patients carrying the T allele present a higher mean survival rate than the other patients (102.3 months vs. 86.4 months, P = 0.020). Using the Cox regression analysis, we found an increased overall survival time for T-carrier patients, when compared with GG genotype, with tumor stage, age and presence of lymph nodes as covariates [hazard ratio (HR), 0.373; 95% CI, 0.181–0.770; P = 0.008]. Among patients (n = 193), RAD51 genotype frequency distributions were not under the influence of clinicopathologic characteristics, namely, treatment response (P = 0.508), recurrence (P = 0.150) and tumor stage (P = 0.250).

Conclusions

This is the first study evaluating the role of the RAD51 G172T genetic variants in cancer prognosis and clinical outcome of cervical cancer patients. Our results indicate an influence of the RAD51 genetic variants in overall survival of cervical cancer. Thereby, RAD51 G172T genotypes may provide additional prognostic information in cervical cancer patients who underwent cisplatin-based chemotherapy in combination with radiotherapy.     

rs4215 SNP in zinc-α2-glycoprotein gene is associated with obesity in Chinese north Han population

Objective

Zinc-α2-glycoprotein (ZAG) has been identified recently as a novel adipokine due to its close link with lipid and glucose metabolism, as well as regulation of body weight. The aim of our present study is to investigate the ZAG genetic polymorphism association with obesity in Chinese north Han population.

Design and methods

Five SNPs of ZAG gene including rs2247607 (A>T), rs4727442 (G>T), rs4215 (A>G), rs2527923 (C>T) and rs2527882 (C>T) were genotyped in 648 overweight/obese patients and 313 healthy controls by TaqMan-PCR methods. Crosstabs statistical analysis method with subjects stratifying by age (≦ 30 y, 31–45 y, ≧ 46 y) and gender was used.

Results

The results showed the constitution of three genotype frequencies in rs4215 (A>G) site significantly differs in male subgroup (aged 31–45 y) between overweight/obese and healthy control group (χ² = 6.401, P = 0.041). GG genotype frequency in overweight/obese group is 19.3% which is much higher than 6.1% in healthy control group. Further statistical analysis under a recessive inheritance model demonstrated odd ratio (OR) for GG vs. AA+AG in overweight/obese group was 3.674 (95% CI 1.049–12.866; P = 0.035). Among three genotypes of rs4215, the subjects with GG genotype have much more higher body weight, BMI, waist circumference and SBP.

Conclusion

Our data, for the first time, suggest the genotypes of rs4215 in ZAG gene are significantly associated with obesity in Chinese north Han population. GG genotype subjects in rs4215 site have an increased susceptibility to obesity when compared with the AA+AG genotype subjects.     

GTP Cyclohydrolase I and Tyrosine Hydroxylase Gene Mutations in Familial and Sporadic Dopa-Responsive Dystonia Patients

Dopa-responsive dystonia (DRD) is a rare inherited dystonia that responds very well to levodopa treatment. Genetic mutations of GTP cyclohydrolase I (GCH1) or tyrosine hydroxylase (TH) are disease-causing mutations in DRD. To evaluate the genotype-phenotype correlations and diagnostic values of GCH1 and TH mutation screening in DRD patients, we carried out a combined study of familial and sporadic cases in Chinese Han subjects. We collected 23 subjects, 8 patients with DRD, 5 unaffected family members, and 10 sporadic cases. We used PCR to sequence all exons and splicing sites of the GCH1 and TH genes. Three novel heterozygous GCH1 mutations (Tyr75Cys, Ala98Val, and Ile135Thr) were identified in three DRD pedigrees. We failed to identify any GCH1 or TH mutation in two affected sisters. Three symptom-free male GCH1 mutation carriers were found in two DRD pedigrees. For those DRD siblings that shared the same GCH1 mutation, symptoms and age of onset varied. In 10 sporadic cases, only two heterozygous TH mutations (Ser19Cys and Gly397Arg) were found in two subjects with unknown pathogenicity. No GCH1 and TH mutation was found in 40 unrelated normal Han Chinese controls. GCH1 mutation is the main etiology of familial DRD. Three novel GCH1 mutations were identified in this study. Genetic heterogeneity and incomplete penetrance were quite common in DRD patients, especially in sporadic cases. Genetic screening may help establish the diagnosis of DRD; however, a negative GCH1 and TH mutation test would not exclude the diagnosis.     

Genetic variation and clonal diversity of the endangered aquatic fern Ceratopteris pteridoides as revealed by AFLP analysis

Ceratopteris pteridoides (Hook.) Hieron. is an endangered aquatic homosporous fern in China. Genetic diversity and structure of eight populations collected from the mid-lower reaches of Yangtze River were investigated using amplified fragment length polymorphisms (AFLPs). A low level of gene diversity was found at the population level (P_p = 17.4%, H_E = 0.039 and I = 0.063), which possibly resulted from its high degree of inbreeding, clonal growth and short life history of this species. C. pteridoides contained high clonal diversity (PD = 0.757, D = 0.992). High population differentiation was revealed by partitioning of genetic diversity (G_ST = 0.707), and the AMOVA analysis consistently showed that 72.3% of the total genetic diversity was attributable to among-population diversity. Based on the genetic information from UPGMA cluster and principal coordinate analysis, two management units have been identified, and translocation within each management unit is recommended.