Biomedical subjects

N Tebib

Publications and source records attributed to N Tebib.

9 recordsLinked to original sources

PubMed2006

Genetic and mutational heterogeneity of autosomal recessive chronic granulomatous disease in Tunisia.

NADPH oxidase, a multi-subunit protein consisting of cytosolic components and the membrane-bound heterodimer, plays an instrumental role in host defence mechanisms of phagocytes. Genetic deficiency of the enzymatic complex results in an inherited disorder, chronic granulomatous disease (CGD), which is characterized by an impaired phagocyte microbicidal activity. X-Linked (XL) CGD results from a mutation in the CYBB gene encoding the gp91phox subunit, while autosomal recessive (AR) CGD is associated with mutations in one of the NCF1, NCF2 and CYBA genes that encode the p47phox, p67phox and p22phox subunits, respectively. In the study reported here, we investigated genetic defects underlying CGD in 15 Tunisian patients from 14 unrelated families. Haplotype analyses and homozygosity mapping with microsatellite markers around known CGD genes assigned the genetic defect to NCF1 in four patients, to NCF2 in four patients and to CYBA in two patients. However, one family with two CGD patients seemed not to link the genetic defect to any known AR-CGD genes. Mutation screening identified two novel mutations in NCF2 and CYBA in addition to the recurrent mutation, DeltaGT, in NCF1 and a splice site mutation previously reported in a North African patient. Our results revealed the genetic and mutational heterogeneity of the AR recessive form of CGD in Tunisia.

Base Sequence↗

PubMed2006

Clinical and mutational investigations of tyrosinemia type II in Northern Tunisia: identification and structural characterization of two novel TAT mutations.

Tyrosinemia type II or Richner-Hanhart Syndrome (RHS) is an autosomal recessive disorder characterized by keratitis, palmoplantar keratosis, mental retardation, and elevated blood tyrosine levels. The disease is due to a deficiency of hepatic cytosolic tyrosine aminotransferase (TATc), an enzyme involved in the tyrosine catabolic pathway. Because of the high rate of consanguinity this disorder seems to be relatively common among the Arab and Mediterranean populations. RHS is characterized by inter and intrafamilial phenotypic variability. A large spectrum of mutations within TATc gene has been shown to be responsible for RHS. In the present study, we report the clinical features and the molecular investigation of RHS in three unrelated consanguineous Tunisian families including 7 patients with confirmed biochemical diagnosis of tyrosinemia type II. Mutation analyses were performed and two novel missense mutations were identified (C151Y) and (L273P) within exon 5 and exon 8, respectively. The 3D-structural characterization of these mutations provides evidence of defective folding of the mutant proteins, and likely alteration of the enzymatic activity. Phenotype variability was observed even among individuals sharing the same pathogenic mutation.

Adult↗

PubMed2004

[Gaucher's disease in Tunisia (multicenter study)].

UNLABELLED: Gaucher's disease is one of the rare lysosomial disease that could receive substitutive enzymatic treatment which may improve considerably the prognosis of certain forms. The purpose of this work is to study the epidemiology of the disease in Tunisia, to highlight the diagnostic and therapeutic difficulties and also to precise our subsequent needs for substitutive medication. PATIENTS AND METHODS: We have conducted a retrospective survey of the hospital wards that were susceptible to take care of patients having Gaucher's disease. These wards are the paediatric, neonatology, internal medicine, haematology, neurology and cardiology wards. RESULTS: In this study we have observed 27 cases of Gaucher's disease over a period of 18 years (1983-2001). The age at onset ranges from birth to 73 years of age, with an average age of 14.5 years. According to the age at onset and the clinical presentation, we classify our patients into: 20 cases of type 1 (74%), three cases of type 2 (12%), and three cases of type 3 (12%), and one case of unspecified type.Gaucher's disease type 1: The age at onset ranged from 10 months to 73 years with an average of 19 years. The main clinical signs that we have observed were splenomegaly, hepatomegaly, pallor, haemorrhagic appearance and also osteoporosis and bone pain observed in 40% of the cases. The diagnosis was based on histology showing the Gaucher's cells in various tissues while the diagnosis obtained by the dosage of glucocerebrosidase took place only in 50% of the cases. The treatment has always been symptomatic (analgesics, transfusion). A splenectomy was performed in 47% of the cases and none of the patients received a specific treatment. The follow-up period ranged from 1 month to 18 years with an average follow-up of 4 years. Among the 12 patients having a follow-up of at least 1 year, we have noticed an improvement after splenectomy in three cases, a stability in three cases and two worsening cases dealing mainly with bone problems. One patient aged 73 died from respiratory problem and three were lost to follow-up. Gaucher's disease type 2: We have observed three cases of Gaucher's disease type 2 diagnosed at 1 day, 45 days and 3 months of age. The visceral manifestations were serious and the neurological features included seizures, hypertony, ocular-nerve palsies and psychometric decline. The three patients died. Gaucher's disease type 3: Three patients were probably suffering from Gaucher's disease type 3 with visceral manifestations observed at the ages of 9 months, 1 year and 3 years, and also neurological signs observed at respective ages of 2.5 and 3 years. Two patients died and the remaining one was lost to follow-up. CONCLUSION: Gaucher's disease is not exceptional in Tunisia. Type 1 is by far the most common one. We have noticed some insufficiency in the diagnosis as the glucocerebrosidase enzymatic dosage was performed only in 50% of the cases as well as therapeutic insufficiency with no prescription of the specific treatment.

Adolescent↗

PubMed1998

[Reference values of urinary orotic acid in a healthy Tunisian population].

BACKGROUND: Orotic acid (OA) is an intermediary metabolite of pyrimidine synthesis. An elevation of urinary orotic acid excretion has been described in congenital defect of the urea cycle enzymes and in primary orotic aciduria. Several techniques have been used to measure OA and many reference values are published without considering age and sex. POPULATION AND METHODS: The reference values of urinary OA excretion, expressed in mumol/mmol of creatinine, are reported in a healthy Tunisan population using a colorimetric method. The study included 20 men and 20 women (age = 31 +/- 11 years) and 30 children aged from 3 days to 8 years. RESULTS: There was a significant increase (P < 0.01) of urinary OA excretion in women (4.38 +/- 1.35) compared to men (3.26 +/- 0.80) and of children (5.03 +/- 1.14) compared to adults (3.82 +/- 1.24). Urinary OA excretion was significantly higher among children aged less than 1 year compared to older children. CONCLUSION: It is necessary for every laboratory practicing this kind of exploration to have its own norms which depend on both age and sex.

Adult↗

PubMed1995