p.F508del in a heterogeneous cystic fibrosis population from Minas Gerais, Brazil

Molecular screening of the CFTR gene in Mexican patients with congenital absence of the vas deferens

BACKGROUND

In several populations CFTR mutations, as well as IVS8-Tn CFTR polymorphism, have been associated with congenital bilateral absence of the vas deferens (CBAVD) and idiopathic obstructive azoospermia diseases. However, the involvement of these mutations in infertility of Mexican males has not been elucidated.

AIMS

We investigated whether CFTR mutations and IVS8-Tn(TG)m polymorphisms are associated with infertility in azoospermic Mexican patients.

METHODS

Sixteen CBAVD and 33 idiopathic azoospermic cases were included. The CFTR gene was sequenced in all CBAVD cases. In the idiopathic azoospermic patients, the p.F508del, p.G542X, p.N1303K, p.S549N, p.I507del, and p.R117H mutations and those detected in our CBAVD cases were screened.

RESULTS

The p.F508del, p.G85E, p.D1152H, and p.W1089X mutations were found in 3 CBAVD patients (18.8%). None of the 9 CFTR mutations screened for in idiopathic azoospermic were found; however, we documented a high frequency of the Gln1463Gln polymorphism in comparison with healthy controls (20% vs 6%; p=0.0029).

CONCLUSIONS

These data showed that the CFTR mutations but not the IVS8-Tn polymorphism are involved in CBAVD etiology in a Mexican population. Nevertheless, other screening strategies should be used to rule out the implication of CFTR mutations in idiopathic azoospermic disease.

Low prevalence of glucose intolerance in racially mixed children with cystic fibrosis

OBJECTIVE

To evaluate glucose tolerance in racially mixed Brazilian youth with cystic fibrosis (CF).

METHODS

Cross-sectional study conducted between August and September 2007, at a reference service for CF, evaluating: glycated hemoglobin (HbA1c), blood glucose, and insulin levels, before and 2 h after a glucose overload.

RESULTS

There were 46 patients aged between 6 yr and 16 yr and 2 months (median: 9 yr and 10 months) of whom 64% were boys. Of these, 26% were Whites; 54.4% Mulattoes; and 19.6% Blacks. HbA1c was normal in all patients. Only one participant (12-yr old) had glucose intolerance. Insulin levels ranged from 1 to 23 µIU/mL (median: 4.5 µIU/mL) at baseline and from 3.2 to 192.1 µIU/mL (median: 11 µIU/mL) after a glucose overload. Insulin resistance evaluated by the HOMA index, stratified by sex and age, was present in three patients. The ΔF508 mutation was present in only 4.3% of the sample, all of them being heterozygous.

CONCLUSIONS

The low prevalence of carbohydrate intolerance in this population is probably a result of their young age. Another possibility is the low frequency of the ΔF508 mutation. Although not conclusive, these data suggest that in addition to age, the genotype:phenotype ratio may influence the development of glucose intolerance in patients with CF.