c.1643_1644delTG XPC mutation is more frequent in Moroccan patients with xeroderma pigmentosum

Xeroderma pigmentosum is a rare autosomal recessive disease characterized by hypersensitivity to UV light which is due to alterations of the nucleotide excision repair pathway. Eight genes (XPA to XPG and XPV) are responsible for the disease. Among them, the XPC gene is known to be the most mutated in Mediterranean patients. The aim of this study was to determine the frequency of the most common XPC mutation and describe the clinical features of Moroccan patients with xeroderma pigmentosum. Twenty four patients belonging to 21 unrelated Moroccan families and 58 healthy subjects were investigated. After clinical examination, the screening for the c.1643_1644delTG (p.Val548AlafsX25) mutation in the XPC gene was performed by PCR and automated sequencing of exon 9 in all patients and controls. The molecular analysis showed that among the 24 patients, 17 were homozygous for the c.1643_1644delTG mutation and all their tested parents were heterozygous, whereas the others (7 patients) did not carry the mutation. The frequency of this mutation was estimated to be 76.19 % (16/21 families). None of the 58 healthy individuals carried this mutation. In addition, clinical investigation showed that the majority of the patients bearing this mutation have the same clinical features. Our results revealed that the p.Val548AlafsX25 mutation is the major cause (76.19 %) of xeroderma pigmentosum in Moroccan families. This would have an important impact on improving management of patients and their relatives.     

Erythropoietin in cancer patients with anemia

OBJECTIVE: The aim of this study is to evaluate the endogenous erythropoietin production in cancer patients with anemia. METHODS: Our prospective study interested 99 cancer patients with anemia from 17 to 80 years old, during the period going from March 2002 to December 2004, and 31 healthy individuals with anemia caused by iron deficiency. A blood sample was collected from each patient, as well as healthy individuals to measure serum erythropoietin, C reactive protein and ferritin. RESULTS: The increase of serum erythropoietin was significantly lower in patients than in healthy individuals (P < 0.05). 25.2% of our cancer patients have inflammatory anemia and 74.7% presented microcytic anemia associated with increase of serum ferririn and CRP. These values were significantly higher than in healthy individuals (p < 0.05). CONCLUSION: Anemia in cancer patients results from activation of inflammatory system, which inhibit erythropoietin production. Apart from etiologic treatments, anemia can be treated with recombinant human erythropoietin.     

Identification of a primarily neurological phenotypic expression of xeroderma pigmentosum complementation group A in a Tunisian family

Xeroderma pigmentosum (XP) is a rare genodermatosis predisposing to skin cancers. The disease is classified into eight groups. Among them, XP group A (XP‐A) is characterized by the presence of neurological abnormalities in addition to cutaneous symptoms. In the present study, we report a particular family with XP‐A in which some members showed an atypical clinical presentation, i.e. unexplained neurological abnormalities with discrete skin manifestations. Molecular investigation allowed identification of a novel XPA mutation and complete phenotype–genotype correlation for this new phenotypic expression of XP‐A.     

Severe phenotypes in two Tunisian families with novel XPA mutations: evidence for a correlation between mutation location and disease severity

Xeroderma pigmentosum (XP) is a rare disorder characterized by a high skin sun-sensitivity predisposing to skin cancers at an early age. Among Tunisian XP patients with an intermediate skin phenotype, 92% presented neurological abnormalities related to XPA gene deficiency. Clinical variability of the XP-A phenotype is associated with a mutational heterogeneity. In the present study, two Tunisian families with severe dermatological and neurological XP phenotypes were investigated in order to determine clinical characteristics and genetic basis. Two Tunisian families with four XP affected children were examined in the Dermatology Department. Clinical features showed severe presentation of the disease. Coding regions of the XPA gene were analysed by direct sequencing. Results showed the presence of a novel mutation, p.E111X, in three patients belonging to the same family and presenting a very severe phenotype i.e. development of skin lesions and neurological signs before 1 year age. For the other patient, we identified a nonsense mutation, p.R207X, already identified in a Palestinian XP-A patient. Identification of novel causing mutations in Tunisian XP-A patients shows the genetic and mutational heterogeneity of the disease in Tunisia. Despite a relatively homogenous mutational spectrum, mutational heterogeneity for rare cases is observed because of the high rate of consanguinity.     

Molecular characterization of a ring chromosome 15 in a fetus with intra uterine growth retardation and diaphragmatic hernia

OBJECTIVE: To improve the phenotype-genotype correlation in terminal 15q deletions and ring chromosome 15 syndrome. METHODS: Echographic examination of fetus. R-banded chromosome and FISH analysis on cultured amniocytes. Microsatellite analysis to determine parental origin of the ring chromosome 15. Fetal autopsy. RESULTS: We report a new case of prenatal diagnosis of congenital diaphragmatic hernia and intrauterine growth retardation in a fetus with ring chromosome 15 involving 15q26.1-qter deletion. CONCLUSION: This case support the evidence that the region 15q26.3 is implicated in intrauterine growth retardation and suggests that the 15q critical region implicated in congenital diaphragmatic hernia is localized in 15q26.1-q26.2.     

Molecular typing of Neisseria perflava clinical isolates

Multilocus sequence typing and pulsed‐field gel electrophoresis were used to type 22 commensal isolates of Neisseria perflava collected by swabbing from neutropenic patients. High genetic diversity was found among our N. perflava clinical isolates.     

Case report of bacteremia due to Neisseria mucosa

Neisseria mucosa, a Gram‐negative diplococcus, is part of normal nasopharyngeal flora. We report a case of bacteremia caused by N. mucosa in a 50‐year‐old neutropenic patient suffering from non‐secretory multiple myeloma stage IIIA. This case underscores that mostly nonpathogenic N. mucosa can cause bacteremia in neutropenic patients who developed mucositis after hematopoietic stem cell transplantation.     

Description of a novel mutation in the atpC gene in optochin-resistant Streptococcus pneumoniae strains isolates from Tunisia

Identification of Streptococcus pneumoniae among other α-haemolytic streptococci is based on phenotypic or genotypic characteristics such as colony morphology, bile solubility and optochin susceptibility. This study reports three optochin-resistant S. pneumoniae strains isolated from immunocompromised patients in Tunisia. The three isolates were positive for the bile solubility test. Biochemical identification with API^® 20 Strep was not discriminatory for two strains. The three strains had different serotypes (6C, 19F and 23F) and three different sequence types (ST386, ST320 and ST326). Sequencing of the atpA and atpC genes for each strain showed only modification in atpC. The mutations Met13→Val or Val48→Ile were observed in two strains. However, in the third strain a novel type of mutation (Val15→Ile) was identified.