Extensive Molecular Analysis of Patients Bearing CFTR-Related Disorders

Abstract

Cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders (CFTR-RDs) may present with pancreatic sufficiency, normal sweat test results, and better outcome. The detection rate of mutations is lower in CFTR-RD than in classic CF: mutations may be located in genes encoding proteins that interact with CFTR or support channel activity. We tested the whole CFTR coding regions in 99 CFTR-RD patients, looking for gene mutations in solute carrier (SLC) 26A and in epithelial Na channel (ENaC) in 33 patients who had unidentified mutations. CFTR analysis revealed 28 mutations, some of which are rare. Of these mutations, RT-PCR demonstrated that the novel 1525-1delG impairs exon 10 splicing; by using minigene analysis, we excluded the splicing effect of three other novel intronic variants. Analysis of SLC26A genes revealed several variants, some of which are novel, that did not affect mRNA expression. Other mutations occurred in the ENaC genes encoding the ENaC subunits, but their frequency did not significantly differ between patients and controls. Our data, although obtained on a preliminary cohort of CFTR-RD patients, exclude a role of mutations in SLC26A and in SCNN genes in the pathogenesis of such disease; we confirm that CFTR analysis has a relevant role in CFTR-RD patients; and it appears mandatory to use CFTR scanning techniques and approaches to reveal the effect of novel mutations.

Prenatal diagnosis of inherited diseases: 20 years’ experience of an Italian Regional Reference Centre

“…Counselling revealed that 20/77 couples were not at high risk (i.e., autosomal recessive diseases in which only one member of the couple was carrier of a mutation). Twenty-six out of 77 couples declined PD because counselling revealed they were carriers of a not severe disease, i.e., in seven cases a female (identified as a carrier through cascade screening) carried a mutation responsible for mild HA; in eight cases a member of the couple had a severe cystic fibrosis transmembrane regulator (CFTR) mutation and the other member had the TG12-5T-470V CFTR haplotype, considered a mild mutation, thus they had a 1:4 risk to generate a newborn affected by a CFTR-related disorder (CFTR-RD), typically much less severe than classic CF [16]; in one couple both members were carrier of a mild mutation of the β-globin gene; in six cases the family-disease was inherited deafness with no other clinical alterations predictable for the newborn; in four cases the members of the couple were carriers of mutations responsible for phenylketonuria. Twelve other women had a spontaneous abortion before PD; 11 planned not to perform PD because it was too hard to make a decision if the result was positive, two because of disagreement with the partner, one for disagreement about PD and finally five couples planned to perform PD in another centre.…”

“…In addition, CGH can be used to analyse chromosomal alterations associated with gain or loss of DNA thereby becoming a complementary approach to karyotyping [23]; 3) Southern blot, long PCR or capillary electrophoresis to assess microsatellite expansion typically found in Huntington's disease [24], fragile X syndrome [25], Friedreich's ataxia [26], DM1 [15], and spinocerebellar ataxia [21]. Furthermore, laboratories must be equipped to perform functional studies to define the pathogenicity of novel mutations [16,27] particularly frequent in X-linked diseases [28].…”

Reports of Three Cases of Atypical Cystic Fibrosis with Azoospermia

“…More than 1.800 mutations in the CFTR gene have been identified [5]; many of which are so rare as to be called 'private' as they are only present within individual families.…”

Genetic investigations in chronic pancreatitis and pancreatic cancer

“…It is conceivable, that mutations of the SLC26A6 anion transporter could influence the effects of smoking, however, we did not find a significant difference between genotype frequencies of smokers and non-smokers (data not shown). Previously, Amato et al (2012) examined SLC26 anion transporter and epithelial Na þ channel genes in 39 patients with CFTR related disorders, and found no association [26]. They described the SLC26A6 variants which we also identified as the p.V206M associated haplotype, however, they did not report linkage of these variants.…”

“…with CFTR related disorders, and found no association. 70 They described the SLC26A6 variants which we also identified as the p.V206M associated haplotype, however, they did not report linkage of these variants.…”