Cystic

brosis transmembrane regulator

mutation and congenital bilateral absence of the

vas deferens: a bad combination for successful

intracytoplasmic sperm injection outcomes

Cystic

brosis (CF) is an autosomal recessive disease

commonly found in Caucasians, and

F508, a major muta-

tion in the gene that encodes cystic

brosis transmembrane

regulator (CFTR), can be identi

ed in over 75% of patients

with CF. Beyond knowing that CFTR promotes a channel

that conducts both Cl

and HCO

, it is unclear how mutations

in the gene encoding this protein can result in male infertility.

An early study on CF adults with azoospermia revealed

congenital bilateral absence of the vas deferens (CBAVD) in

all men

(1)

It is speculated that CFTR has an important role in sperm

function well beyond CBAVD and CF. In the study by Lu et al.

(2)

, sperm obtained from men with both CFTR mutations and

CBAVD were associated with an increased risk of miscarriage

and stillbirth after intracytoplasmic sperm injection (ICSI) as

compared with men without either CFTR or CBAVD. It is inter-

esting that two recent studies from the People

’

s Republic of

China have also demonstrated an association between CFTR

and sperm function. One study shows decreased motility

and fertilizing capacity in sperm obtained from elderly men

with CFTR mutations

(3)

. The other study, which evaluated

men with azoospermia, observed down-regulation of CFTR

in testicular samples,

(4)

again indicating a bigger role for

CFTR in male fertility beyond CBAVD and CF.

In the Lu et al.

(2)

study, the prevalence of CFTR muta-

tions in the female partners is not clear because they were

not tested. It is important to test the female partner as well

for CFTR gene abnormalities before performing ICSI using

sperm from a man with either CBAVD or a known CFTR mu-

tation because of the risk that she may also be a carrier. Infor-

mation on mutations and carrier status is important for

counseling the couple regarding the future risk of CF in

offspring as well as the health effects of CFTR mutations

(5)

Ranjith Ramasamy, M.D.

Larry I. Lipshultz, M.D.

Baylor College of Medicine, Houston, Texas

http://dx.doi.org/10.1016/j.fertnstert.2014.02.011

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REFERENCES

Kaplan E, Shwachman H, Perlmutter AD, Rule A, Khaw KT, Holsclaw DS.

Reproductive failure in males with cystic

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Lu S, Cui Y, Li X, Zhang H, Liu J, Kong B, et al. Association of cystic

brosis

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–

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cystic

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Airway in

ﬂ

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–

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VOL. 101 NO. 5 / MAY 2014