Large deletions in the CFTR gene: clinics and genetics in Swiss patients with CF

Cystic fibrosis (CF) is the most common life-shortening autosomal recessive disorder in Caucasians, and is associated with at least one mutation on each CF transmembrane conductance regulator (CFTR) allele. Some patients, however, with only one identifiable point mutation carry on the other allele, a large deletion that is not detected by conventional screening methods. The overall frequency of large deletions in patients with CF is estimated to be 1-3%. Using the CFTR Multiplex Ligation dependent Probe Amplification Kit (MRC-Holland, Amsterdam, Netherlands) that allows the exact detection of copy numbers from all 27 exons in the CFTR gene, we screened 50 patients with only one identified mutation for large deletions in the CFTR gene. Each detected deletion was confirmed using our real-time polymerase chain reaction (PCR) assay and deletion-specific PCR reactions using junction fragment primers. We detected large deletions in eight patients (16%). These eight CF alleles belong to four different deletion types (CFTRindel2, CFTRdele14b-17b, CFTRdele17a-17b and CFTRdele 2-9) whereof the last is novel. Comparing detailed clinical data of all these patients with CF and the molecular genetic findings, we were able to elaborate criteria for deletion screenings and possible genotype-phenotype associations. In conclusion, we agree with other authors that deletion screenings should be implemented in routine genetic diagnostics of CF.

[Acute hemoptysis]

Hemoptysis is a frightening symptom for patients and is often a manifestation of a severe underlying disease. The main threat in the acute phase remains asphyxiation resulting from flooding of the airways with blood. In massive hemoptysis, correctly inserted double-lumen endotracheal tubes maintain airway patency. Finding the etiology and site of the hemoptysis is imperative. After excluding extrapulmonary sites of bleeding, computed tomography and bronchoscopy are complementary and may indicate pathologies not detectable by chest radiograph. An interdisciplinary approach including pneumologist, thoracic surgeon and radiologist in the management of hemoptysis is essential.

[Tachypnea--when breathing induces panic]

Eine gestörte Atmung macht Angst. Zur besseren Charakterisierung sind die Begriffe Tachypnoe, Dyspnoe und Hyperventilation zu differenzieren, welche verschiedene Zustände und Sensationen der Atmung beschreiben. Die wichtigsten pathophysiologischen Mechanismen der Atemnot, wie die Erhöhung der Atemimpedanz, die Störung der Atemmuskulatur, die abnorme Erhöhung der Ventilation und die abnormen Blutgase erklären die verschiedenen Differenzialdiagnosen und leiten über zu den Therapien, welche leider nicht selten symptomatisch bleiben. Möglichkeiten zur Symptomlinderung sind Rehabilitationstraining, Medikamente bzw. das Meiden verschlimmernder Substanzen, Sauerstoff und spezielle Ventilationshilfen. Am wichtigsten ist aber ein möglichst umfassender Therapieansatz mit Einbezug der psychischen und sozialen Patientenressourcen.

[Snoring--when is etiological assessment necessary?]

Snoring is more than a social problem. Snoring is a sound produced by the vibrating structures of the upper airway. If clinical signs like sleepiness, fatigue, hypertension or vascular disease are present or if a surgical procedure for the treatment of snoring is considered, further investigations (respiratory polygraphy or full nocturnal polysomnography) should be performed. If sleep apnea is demonstrated, non-surgical approaches may be more promising.

Outcome after unilateral lung volume reduction surgery in patients with severe emphysema

OBJECTIVE

Bilateral lung volume reduction surgery (LVRS) has emerged as a palliative treatment option in patients with severe pulmonary emphysema. However, it is not known if a sustained functional improvement can be obtained using an unilateral approach.

METHODS

We hypothesized that a palliative effect can also be obtained by unilateral LVRS and prospectively assessed lung function, walking distance, and dyspnea before and 3, 6, 12, 18, 24 and 36 months after unilateral LVRS.

RESULTS

Twenty-eight patients were operated by the use of video-assisted thoracoscopic surgery (VATS) with a mean follow-up of 16.5 months (range 3-36 months). Forced expiratory volume in 1 s (FEV1) was significantly improved up to 3 months (1007+/-432 compared to 1184+/-499 ml, P<0.001), residual volume up to 24 months (4154+/-1126 compared to 3390+/-914 ml, P<0.01), dyspnea up to 12 months (modified Borg dyspnea scale 6.6+/-1.8 compared to 3.9+/-1.8, P=0.01) and walking distance up to 24 months (343+/-107 compared to 467+/-77 m, P<0.05) after unilateral LVRS compared to preoperative values. Overall, 25 of 28 patients reported a subjective benefit after unilateral LVRS. There was no 30-day mortality. Only two patients required surgery on the contralateral side after 4.5 and 6 months, respectively, both suffering from alpha-1-antitrypsin deficiency.

CONCLUSIONS

Unilateral LVRS by the use of VATS results in a sustained beneficial effect, improving walking distance and dyspnea for up to 24 months in patients with severe emphysema. The preservation of the contralateral side for future intervention if required renders unilateral LVRS an attractive concept in this difficult palliative situation.

[Giant cell arteritis--a genetically-determined disease?]

We report on two siblings with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR). Temporal artery biopsies revealed GCA in three cases, and sclerosis of the wall of the temporal artery in one case. The HLA haplotype was identical in the first pair, and in the second pair HLA-A2, HLA-B39 and HLA-DR53 were identical. In three patients HLA-DR4 was demonstrated. Cases of familial aggregation of GCA have been reported in the literature. In several reports an increased prevalence of HLA-DR4 was described (about 40% of patients with GCA, compared with about 13% in the European population). HLA-DR4 was observed in three of our four patients and a haploidentity was found in one pair. Based on our observation and the results published in the literature, it seems probable that giant cell arteritis--a typical disease of advanced age--has at least partially a genetic basis.