Genetic analysis of Rwandan patients with cystic fibrosis-like symptoms: identification of novel cystic fibrosis transmembrane conductance regulator and epithelial sodium channel gene variants.

in CHEST (2009), 135(5), 1233-42

BACKGROUND: The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CF transmembrane conductance regulator (CFTR) loss of function and an abnormal interaction ... [more ▼]

BACKGROUND: The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CF transmembrane conductance regulator (CFTR) loss of function and an abnormal interaction between CFTR and the epithelial sodium channel (ENaC). A few patients were described with CF-like symptoms, a single CFTR mutation, and an ENaC mutation. METHODS: To study African patients with CF-like symptoms and to relate the disease to gene mutations of both CFTR and ENaC genes, we collected clinical data and DNA samples from 60 African patients with a CF phenotype. The CFTR gene was first analyzed in all patients by denaturing high-performance liquid chromatography followed by direct sequencing; whereas, the sodium channel non-voltage-gated 1 alpha (SCNN1A), sodium channel non-voltage-gated 1 beta (SCNN1B), and sodium channel non-voltage-gated 1 gamma (SCNN1G) subunits of the ENaC gene were analyzed by sequencing in the five patients who carried only one CF mutation. The frequency of all identified ENaC variants was established in a control group of 200 healthy individuals and in the 55 CF-like patients without any CFTR mutation. RESULTS: Three CFTR mutants, including one previously undescribed missense mutation (p.A204T), and a 5T/7T variant were identified in five patients. ENaC gene sequencing in these five patients detected the following eight ENaC variants: c.72T>C and p.V573I in SCNN1A; p.V348M, p.G442V, c.1473 + 28C>T, and p.T577T in SCNN1B; and p.S212S and c.1176 + 30G>C in SCNN1G. In the 55 CF-like patients without any CFTR mutation, we identified five of these eight ENaC variants, including the frequent p.G442V polymorphism, but we did not detect the presence of the p.V348M, p.T577T, and c.1176 + 30G>C ENaC variants. Moreover, these last three ENaC variants, p.V348M, p.T577T, and c.1176 + 30G>C, were not found in the control group. CONCLUSION: Our data suggest that CF-like syndrome in Africa could be associated with CFTR and ENaC mutations. [less ▲]

Germline PTPN11 missense mutation in a case of Noonan syndrome associated with mediastinal and retroperitoneal neuroblastic tumors.

in Cancer Genetics & Cytogenetics (2008), 182(1), 40-2

Noonan syndrome (NS) is an autosomal dominant disorder characterized by short stature, typical craniofacial dysmorphism, skeletal anomalies, congenital heart defects, and predisposition to malignant ... [more ▼]

Noonan syndrome (NS) is an autosomal dominant disorder characterized by short stature, typical craniofacial dysmorphism, skeletal anomalies, congenital heart defects, and predisposition to malignant tumors. In approximately 50% of cases, the disease is caused by missense mutations in the PTPN11 gene. To date, solid tumors, and particularly brain tumors and rhabdomyosarcomas, have been documented in patients with NS; however, few cases of neuroblastoma associated with NS have been reported. Here we report an unusual case of neuroblastoma with mediastinal, retroperitoneal, and medullar locations associated in a NS patient carrying a PTPN11 germline missense mutation (p.G60A). This missense mutation occurs within the N-SH2 domain of the PTPN11 gene and has been reported to be associated with acute leukemia in NS patients. The association of this p.G60A PTPN11 mutation with neuroblastoma provides new evidence that gain of function PTPN11 mutations may play an important role in the pathogenesis of solid tumors associated with Noonan syndrome. [less ▲]

Genetic Analysis of Rwandan Patients With Cystic Fibrosis-Like Symptoms: Identification of Novel Cystic Fibrosis Transmembrane Conductance Regulator and Epithelial Sodium Channel Gene Variants.

in CHEST (2008)

Background The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CFTR loss of function and of an abnormal interaction between CFTR and ENaC. A few patients were ... [more ▼]

Background The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CFTR loss of function and of an abnormal interaction between CFTR and ENaC. A few patients were described with CF-like symptoms, a single CFTR mutation and an ENaC mutation. Methods To study African patients with CF-like symptoms and to relate the disease to gene mutations of both CFTR and ENaC genes, we collected clinical data and DNA samples from 60 African patients with a CF phenotype. The CFTR gene was first analyzed in all patients by dHPLC followed by direct sequencing, whereas the SCNN1A, SCNN1B and SCNN1G subunits of ENaC gene were analyzed by sequencing in the five patients who carried only one CF mutation. The frequency of all identified ENaC variants was established in a control group of 200 healthy individuals and in the 55 CF-like patients without any CFTR mutation Results Three CFTR mutants, including one previously undescribed missense mutation (p.A204T), and a 5T/7T variant were identified in five patients. ENaC gene sequencing in these 5 patients detected 8 ENaC variants: c.72T>C and p.V573I in SCNN1A; p.V348M, p.G442V, c.1473 + 28C>T, and p.T577T in SCNN1B; and p.S212S, c.1176 + 30G>C in SCNN1G. In the 55 CF-like patients without any CFTR mutation, we identified five of these eight ENaC variants, including the frequent p.G442V polymorphism, but we did not detect the presence of the p.V348M, p.T577T, and c.1176 + 30G>C ENaC variants. Moreover, these last three ENaC variants, p.V348M, p.T577T, and c.1176 + 30G>C, were not found in the control group. Conclusion Our data suggest that CF-like syndrome in Africa could be associated with CFTR and ENaC mutations. [less ▲]

Le syndrome de Hutchinson-Gilford (progeria): analyse clinique et moleculaire chez une patiente d'origine africaine

in Revue Médicale de Liège (2007), 62(3), 155-8

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare genetic disease characterized by an early onset of several clinical features including premature ageing in children. Approximately 80% of ... [more ▼]

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare genetic disease characterized by an early onset of several clinical features including premature ageing in children. Approximately 80% of HGPS cases are caused by a de novo single-base pair substitution c.1824 C>T (GGC > GGT, p.Gly608Gly) within the exon 11 of the LMNA gene which codes for lamins A and C proteins. This mutation creates an abnormal splice donor site, leading to the formation of a truncated lamin A protein. Only a very few cases of African patients with HGPS have been reported, but none of them has been characterized at the molecular level. We report here a 12 year-old-girl African patient with HGPS, in whom the p.Gly608Gly heterozygous disease-causing mutation was found. [less ▲]

Precocious puberty associated with partial trisomy 18q and monosomy 11q

in Genetic Counseling (Geneva, Switzerland) (2007), 18(2), 201-207

We report a 10-years-old female patient with a partial trisomy 18q and monosomy 11q due to a maternal translocation. The phenotype of our proband is partially common with Jacobsen syndrome and duplication ... [more ▼]

We report a 10-years-old female patient with a partial trisomy 18q and monosomy 11q due to a maternal translocation. The phenotype of our proband is partially common with Jacobsen syndrome and duplication 18q but she has also some atypical anomalies such as precocious puberty, a retinal albinism and hypermetropia. Based on cytogenetics and FISH analysis, the karyotype of the proband was 46,XX,der(11)t(11;18)(q24;q13). To the best of our knowledge, this is the first report of precocious puberty associated with either dup(18q) or del(11q) syndromes. [less ▲]