Two novel CYP11B1 mutations in congenital adrenal hyperplasia due to steroid 11ß hydroxylase deficiency in a Tunisian family.

Steroid 11ß hydroxylase deficiency (11ß-OHD) (OMIM # 202010) is the second most common form of congenital adrenal hyperplasia (CAH), accounting for 5-8% of all cases. It is an autosomal recessive enzyme defect impairing the biosynthesis of cortisol. The CYP11B1 gene encoding this enzyme is located on chromosome 8q22, approximately 40kb from the highly homologous CYP11B2 gene encoding for the aldosterone synthase. Virilization and hypertension are the main clinical characteristics of this disease. In Tunisia, the incidence of 11ß-OHD appears higher due to a high rate of consanguinity (17.5% of congenital adrenal hyperplasia). The identical presentation of genital ambiguity (females) and pseudo-precocious puberty (males) can lead to misdiagnosis with 21 hydroxylase deficiency. The clinical hallmark of 11ß hydroxylase deficiency is variable, and biochemical identification of elevated precursor metabolites is not usually available. In order to clarify the underlying mechanism causing 11ß-OHD, we performed the molecular genetic analysis of the CYP11B1 gene in a female patient diagnosed as classical 11ß-OHD. The nucleotide sequence of the patient's CYP11B1 revealed two novel mutations in exon 4: a missense mutation that converts codon AGT (serine) to ATT (isoleucine) (c.650G>T; p.S217I) combined with an insertion of a thymine at the c.652-653 position (c.652_653insT). This insertion leads to a reading frame shift, multiple incorrect codons, and a premature stop in codon 258, that drastically affects normal protein function leading to a severe phenotype with ambiguous genitalia of congenital adrenal hyperplasia due to 11ß hydroxylase deficiency.

[Idiopathic steroid-resistant nephrotic syndrome in child : study of 20 cases]. / Syndrome néphrotique idiopathique corticorésistant de l'enfant : Etude de 20 cas.

BACKGROUND: Idiopathic steroid-resistant nephrotic syndrome (ISRNS) is rare and represents a significant therapeutic dilemma for paediatricians and paediatric nephrologists. AIM: To analyze characteristics of the ISRNS in the child. METHODS: Retrospective study of 20 cases of ISRNS enrolled in paediatric department of nephrology in Sahloul hospital (Tunisia) between June 1993 and December 2007 (14 years period). RESULTS: There were eight girls and 12 boys (mean age: 5.8± 3.7 years) originating from the center or the south of Tunisia. Eight of them had a minimal-change disease (MCD), 11 a focal and segmental glomerulosclerosis (FSGS) and one a mesangioproliferative glomerulonephritis (MePGN). In this group, no family form could be identified. All patients were treated by cyclosporine associated with low dose of steroid. We noted a complete remission (CR) in nine cases, partial remission (PR) in three cases and no response to cyclosporine in eight cases. Among patients with CR, six presented MCD and three a FSGS. In this group, we observed relapse of nephrotic syndrome in six cases. End stage renal disease (ESRD) was noted in 10 patients of which five not responded to cyclosporine, two initially having presented a RC and three having since the beginning a PR. Among them, two only could be grafted; one relapses on transplant was observed with a single patient initially presenting a secondarily transformed MePGN in FSGS. CONCLUSION: Our study confirms the clinical, histological and evolutive heterogeneity of idiopathic steroid-resistant nephrotic syndrome. Although there is any therapeutic consensus in this domain, cyclosporine remains indicated in first intention in sporadic forms of ISRNS. On the other hand, renal transplantation constitutes the only therapeutic alternate in genetic forms that constantly evolve at ESRD.

Subtelomeric Rearrangements in Patients with Recurrent Miscarriage.

BACHGROUND: The subtelomeric rearrangements are increasingly being investigated in cases of idiopathic intellectual disabilities (ID) and congenital abnormalities (CA) but are also thought to be responsible for unexplained recurrent miscarriage (RM). Such rearrangements can go unnoticed through conventional cytogenetic techniques and are undetectable even with high-resolution molecular cytogenetic techniques such as array comparative genomic hybridization (aCGH), especially when DNA of the stillbirth or families are not available. The aim of the study is to evaluate the rate of subtelomeric rearrangements in patients with RM. MATERIALS AND METHODS: In this cross-sectional study, fluorescent in situ hybridization (FISH), based on ToTelVysion telomeric probes, was undertaken for 21 clinically normal couples exhibiting a "normal" karyotype with at least two abortions. Approximately 62% had RM with a history of stillbirth or CA/ID while the other 38% had only RM. RESULTS: FISH detected one cryptic rearrangement between chromosomes 3q and 4p in the female partner of a couple (III:4) [46,XX,ish t(3;4)(q28-,p16+;p16-,q28+)(D3S4559+,D3S4560-,D4S3359+; D3S4560+, D4S3359- ,D4S2930+)] who presented a history of RM and family history of ID and CA. Analysis of the other family members of the woman showed that her sisters (III:6 and III:11) and brother (III:8) were also carriers of the same subtelomeric translocation t(3;4)(q28;p16). CONCLUSION: We conclude that subtelomeric FISH should be undertaken in couples with RM especially those who not only have abortions but also have had at least one child with ID and/or CA, or other clinically recognizable syndromes. For balanced and cryptic anomalies, subtelomeric FISH still remains the most suitable and effective tool in characterising such chromosomal rearrangements in RM couples.

Oxidant, antioxidant status and metabolic data in patients with beta-thalassemia.

BACKGROUND: In beta-thalassemia major impaired biosynthesis of beta globin leads to accumulation of unpaired alpha globin chain. An iron overload, usually observed, generates oxygen-free radicals and peroxidative tissue injury. AIM: To investigate hematological parameters, oxidative stress and the antioxidant capacity in beta-thalassemia patients compared to control subjects in order to determine their impact in several organs functions. METHODS: This study was conducted on 56 beta-thalassemia major patients compared to 51 healthy subjects. We determined metabolic parameters (glycaemia, lipid parameters, electrolytes, iron indices, hepatic, renal and heart functions tests), plasmatic thiobarbituric acid reactive substances (TBARS), plasmatic peroxyl radical trapping potential (TRAP), plasmatic superoxide dismutase (SOD), erythrocyte gluthathione peroxidase (GPX), plasmatic vitamin E, vitamin A and trace elements. RESULTS: Except triglycerides, lipid fractions were significantly decreased in beta-thalassemia compared to controls. Serum ferritin, iron, TBARS concentrations, SOD and GPX activities were significantly increased. But TRAP, vitamin E and zinc concentrations were significantly decreased. CONCLUSION: Our findings confirm the peroxidative status generated by iron overload in beta-thalassemia major patients and highlight the rapid formation of marked amounts of TBARS and the increase of SOD and GPX activity. Our study suggested that in beta-thalassemia the first organ impaired is the liver.

[Cardiovascular manifestations of Kawasaki syndrome. Value of echocardiography in diagnosis and progression]. / Manifestations cardiovasculaires du syndrome de Kawasaki. Apport de l'échocardiographie dans le diagnostic et l'évolution.

Seven children with suspected Kawasaki disease were studied by echocardiogram. Coronary abnormalities occurred in all patients, associated with: thrombosis (2 patients) small pericardial effusion (2 patients) poor ventricular function (2 patients), moderate mitral regurgitation (2 patients). Patients received treatment with intravenous gamma globulin, aspirin, and anticoagulant. Echocardiogram abnormalities disappeared between 1 and 26 months after the onset of the disease; only persist coronary hyperechogenecity in 6 patients.

Correlation of SMN2, NAIP, p44, H4F5 and Occludin genes copy number with spinal muscular atrophy phenotype in Tunisian patients.

OBJECTIVES: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder which is characterized by a high clinical variability with severe, intermediate, mild and adult forms. These forms are caused, in 95% of cases, by a homozygous deletion of exon 7 of SMN1 gene. Our purpose was the determination of a possible genotype-phenotype correlation between the copy number of SMN2, NAIP, p44, H4F5 and occludin genes localized in the same SMN1 region (5q13) and the severity of the disease in SMA Tunisian patients. PATIENTS AND METHODS: Twenty six patients affected by SMA were enrolled in our study. MLPA and QMPSF were used to measure copy numbers of these genes. RESULTS: We found that 31.3% of type I patients carried one copy of SMN2, while all patients of other forms had at least 2 copies. NAIP was absent in 87.5% of type I patients. Furthermore, all SMA type I patients had one copy of H4F5. No correlation was found for p44 and occludin genes. CONCLUSION: There is a close relationship between SMN2, NAIP and H4F5 gene copy number and SMA disease severity, which is compatible with the previous reports.

Steroid 21-hydroxylase gene mutational spectrum in 50 Tunisian patients: characterization of three novel polymorphisms.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease of steroid biosynthesis in humans. More than 90% of all CAH cases are caused by mutations of the 21-hydroxylase gene (CYP21A2), and approximately 75% of the defective CYP21A2 genes are generated through an intergenic recombination with the neighboring CYP21A1P pseudogene. In this study, the CYP21A2 gene was genotyped in 50 patients in Tunisia with the clinical diagnosis of 21-hydroxylase deficiency. CYP21A2 mutations were identified in 87% of the alleles. The most common point mutation in our population was the pseudogene specific variant p.Q318X (26%). Three novel single nucleotide polymorphism (SNP) loci were identified in the CYP21A2 gene which seems to be specific for the Tunisian population. The overall concordance between genotype and phenotype was 98%. With this study the molecular basis of CAH has been characterized, providing useful results for clinicians in terms of prediction of disease severity, genetic and prenatal counseling.