Novel splice site IDUA gene mutation in Tunisian pedigrees with hurler syndrome.

BACKGROUND: The mucopolysaccharidosis type I (MPS I) is a lysosomal storage disease resulting from the defective activity of the enzyme α-L-iduronidase (IDUA). The disease has three major clinical subtypes (severe Hurler syndrome, intermediate Hurler-Scheie syndrome and attenuated Scheie syndrome). We aim to identify the genetic variants in MPS I patients and to investigate the effect of the novel splice site mutation on splicing of IDUA- mRNA variability using bioinformatics tools. METHODS: The IDUA mutations were determined in four MPS I patients from four families from Northern Tunisia, by amplifying and sequencing each of the IDUA exons and intron-exon junctions. RESULTS: One novel splice site IDUA mutation, c.1650 + 1G > T in intron 11 and two previously reported mutations, p.A75T and p.R555H, were detected. The patients in families 1 and 2 who have the Hurler phenotype were homozygotes for the novel splice site mutation c.1650 + 1G > T. The patient in family 3, who also had the Hurler phenotype, was a compound heterozygote for the novel splice site mutation c.1650 + 1G > T and for the previously reported missense mutation p.A75T. The patient in family 4 who had the Hurler-Scheie phenotype was a compound heterozygote for the novel splice site mutation c.1650 + 1G > T and for the previously reported missense mutation p.R555H. In addition, four known IDUA polymorphisms were identified. Bioinformatics tools allowed us to associate the variant c.1650 + 1G > T with the severe clinical phenotype of MPS I. This variant affects the essential nucleotide + 1 (G to T) of the donor splice site of IDUA intron 11. The G > T in intron 11 leads to wild type donor site broken with minus 19.97% value compared to normal value with 0%, hence the new splice site acceptor has plus 5.59%. CONCLUSIONS: The present findings indicate that the identified mutations facilitate the accurate carrier detection (genetic counseling of at-risk relatives) and the molecular prenatal diagnosis in Tunisia.

Molecular analysis in a GALNS study cohort of 15 Tunisian patients: description of a novel mutation.

BACKGROUND: Mucopolysaccharidosis type IVA (MPS IVA) is an autosomal recessive disease caused by the deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS). The purpose of this study was to analyze the GALNS mutations and the haplotypes associated. METHODS: Mutation screening of the GALNS gene was performed by direct sequence analysis using DNA samples from 15 unrelated Tunisian MPS IVA patients. We also analyzed the haplotypes associated with the novel mutation and with the other reported GALNS mutations. RESULTS: We have identified an unreported missense mutation p.D288G (c.863A > G) in one patient, the most frequently c.120 + 1G > A (IVS1 + 1G > A) mutation in eleven MPS IVA patients and three previously reported mutations p.G66R, p.A85T and p.R386C on the other MPS IVA patients. All the studied patients were homozygous for these identified mutations. Bioinformatics analysis predicted the novel mutation as being probably pathogenic. These findings with the unobserved p.D288G mutation in controls subjects, suggested that it is a disease-causing mutation, which was correlated with the severe phenotype observed in the patients. We have found that the two GALNS unreported and reported mutations, respectively p.D288G and p.R386C, were associated with a common and specific haplotype. CONCLUSION: Our results were in agreement with previous reports from Tunisia, suggesting, on one hand the genotype/phenotype correlations in MPS IVA patients and the other hand the haplotype analyses were useful for determination of mutation origin in Tunisian population.

Genetic basis of cystinosis in Tunisian patients: Identification of novel mutation in CTNS gene.

Nephropathic cystinosis (NC) is an autosomal recessive disorder characterized by defective transport of cystine across the lysosomal membrane and resulting in renal, ophthalmic, and other organ abnormalities. Mutations in the CTNS gene cause a deficiency of the transport protein, cystinosin. This study was performed to investigate mutations of the CTNS gene in three Tunisian families with NC. Polymerase chain reaction (PCR), ARMS multiplex PCR and direct sequencing were performed for molecular characterization of the CTNS gene in 3 unrelated Tunisian patients and their parents. Based on family history, prenatal diagnosis (PND) was performed in fetal DNA isolated from chorionic villi obtained at 10-12  weeks of gestation. None of the patients showed the most common 57-kb deletion in heterozygous or homozygous status. One patient was homozygous for the previously reported mutation c.1515G > A (p.G308R). One patient presented the novel gross deletion of 20,327 bp. One was homozygote for the previously reported mutation c.771_793del (p.Gly258Serfs*30). In addition, eight polymorphisms were identified in the 3 patients and their parents. The prenatal diagnosis in one family showed that the fetus DNA was heterozygous for the c.771_793del (p.Gly258Serfs*30) mutation. This study expands the mutational and population spectrum of NC, representing the first molecular diagnosis of NC in Tunisian population. The mutation screening of the CTNS gene was used for prenatal diagnosis to prevent and/or limit this inheritable disease in our country where the families are particularly large and have a high rate of consanguinity.

Placental infiltration of inflammatory markers in gestational diabetic women.

Gestational diabetes mellitus (GDM) is pathology of glucose intolerance during pregnancy. It is influenced by maternal hyperglycemia and insulinemia through placental circulation. The study was undertaken to investigate the implication of pro-inflammatory factors in the placenta of GDM women. Thirty GDM women have delivered macrosomic babies, and 30 healthy age-matched pregnant women have delivered non macrosomic babies, were recruited in the study. The mRNAs encoding for IL-6, TLR4, TGF-ß, CD68, CD14, EMR-1, CCL2, TCR-α, T-bet, GATA-3, leptin and adiponectin were quantified in placental samples by using RT-qPCR. The mRNA expression of the pro-inflammatory factors, i.e., IL-6, TLR4 and TGF-ß, was increased in GDM placenta. The mRNA expression of markers of infiltration of macrophage, i.e., CD68, CD14 and EMR-1, was higher in the GDM placenta than the control placenta. The expression of mRNA of TCR-α, an indicator of T-cell infiltration, was significantly higher in the GDM placenta. Interestingly, the expression of mRNA of GATA-3, an indicator of Th2 phenotype differentiation, was unregulated in the GDM placenta. Leptin and adiponectin mRNAs were also significantly increased in the placenta of the GDM group. Our results revealed that there is an increase of inflammation in the GDM placenta which might be involved, in part, in the pathogenesis of macrosomia.

Anti-hyperglycemic effects of three medicinal plants in diabetic pregnancy: modulation of T cell proliferation.

BACKGROUND: Populations in Africa mostly rely on herbal concoctions for their primarily health care, but so far scientific studies supporting the use of plants in traditional medicine remain poor. The present study was undertaken to evaluate the anti-hyperglycemic effects of Picralima nitida (seeds), Nauclea latifolia (root and stem) and Oxytenanthera abyssinica (leaves) commonly used, in diabetic pregnancy. METHODS: Pregnant wistar rats, rendered diabetic by multiple low injections of streptozotocin, were treated with selected plant extracts based on their antioxidant activities. Vitamin C concentrations, fatty acid compositions and phytochemical analysis of plants extracts were determined. Effect of selected plant extracts on human T cell proliferation was also analysed. RESULTS: All analysed plant extracts exhibited substantial antioxidant activities probably related to their content in polyphenols. Picralima nitida exhibited the highest antioxidant capacity. Ethanolic and butanolic extracts of Picralima nitida, butanolic extract of Nauclea latifolia and ethanolic extract of Oxytenanthera abyssinica significantly decreased hyperglycemia in the diabetic pregnant rats. Butanolic extract of Picralima, also appeared to be the most potent immunosuppressor although all of the analysed extracts exerted an immunosuppressive effect on T cell proliferation probably due to their linolenic acid (C18:3n-3) and/or alkaloids content. Nevertheless, all analysed plants seemed to be good source of saturated and monounsaturated fatty acids. CONCLUSION: By having antioxidant, anti-hyperglycemic and immunosuppressive activities, these plants could be good candidates in the treatment of diabetes and diabetic pregnancy.

Growth factor concentrations and their placental mRNA expression are modulated in gestational diabetes mellitus: possible interactions with macrosomia.

BACKGROUND: Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during pregnancy. GDM is a well known risk factor for foetal overgrowth, termed macrosomia which is influenced by maternal hypergycemia and endocrine status through placental circulation. The study was undertaken to investigate the implication of growth factors and their receptors in GDM and macrosomia, and to discuss the role of the materno-foeto-placental axis in the in-utero regulation of foetal growth. METHODS: 30 women with GDM and their 30 macrosomic babies (4.75 +/- 0.15 kg), and 30 healthy age-matched pregnant women and their 30 newborns (3.50 +/- 0.10 kg) were recruited in the present study. Serum concentrations of GH and growth factors, i.e., IGF-I, IGF-BP3, FGF-2, EGF and PDGF-B were determined by ELISA. The expression of mRNA encoding for GH, IGF-I, IGF-BP3, FGF-2, PDGF-B and EGF, and their receptors, i.e., GHR, IGF-IR, FGF-2R, EGFR and PDGFR-beta were quantified by using RT-qPCR. RESULTS: The serum concentrations of IGF-I, IGF-BP3, EGF, FGF-2 and PDGF-B were higher in GDM women and their macrosomic babies as compared to their respective controls. The placental mRNA expression of the growth factors was either upregulated (FGF-2 or PDGF-B) or remained unaltered (IGF-I and EGF) in the placenta of GDM women. The mRNA expression of three growth factor receptors, i.e., IGF-IR, EGFR and PDGFR-beta, was upregulated in the placenta of GDM women. Interestingly, serum concentrations of GH were downregulated in the GDM women and their macrosomic offspring. Besides, the expression of mRNAs encoding for GHR was higher, but that encoding for GH was lower, in the placenta of GDM women than control women. CONCLUSIONS: Our results demonstrate that growth factors might be implicated in GDM and, in part, in the pathology of macrosomia via materno-foeto-placental axis.

Antioxidant status and circulating lipids are altered in human gestational diabetes and macrosomia.

Fetuses from mothers with gestational diabetes are at increased risk of developing neonatal macrosomia and oxidative stress. We investigated the modulation of antioxidant status and circulating lipids in gestational diabetic mothers and their macrosomic babies and in healthy age-matched pregnant women and their newborns. The serum antioxidant status was assessed by employing anti-radical resistance kit (KRL; Kirial International SA, Couternon, France) and determining levels of vitamin A, C, and E and the activity of superoxide dismutase (SOD). Circulating serum lipids were quantified, and lipid peroxidation was measured as the concentrations of serum thiobarbituric acid-reactive substances (TBARS). As compared with non-diabetic mothers, gestational diabetic women exhibited decreased levels of vitamin E and enhanced concentrations of vitamin C without any changes in vitamin A. Vitamin A and C levels did not change in macrosomic babies except vitamin E whose levels were lower in these infants than in the newborns of non-diabetic mothers. Gestational diabetes mellitus (GDM) and macrosomia were also associated with impaired SOD activities and enhanced TBARS levels. Globally, total serum antioxidant defense status in diabetic mothers and their macrosomic babies was diminished as compared with control subjects. Triglyceride and cholesterol concentrations did not differ significantly between gestational diabetic and control mothers; however, macrosomia was associated with enhanced plasma cholesterol and triglyceride levels. These results suggest that human GDM and macrosomia are associated with downregulation of antioxidant status, and macrosomic infants also exhibit altered lipid metabolism.