Sons conceived by assisted reproduction techniques inherit deletions in the azoospermia factor (AZF) region of the Y chromosome and the DAZ gene copy number.
BACKGROUND
Deletions in the azoospermia factor (AZF) region of the Y chromosome are frequent in infertile men. The clinical consequences and the mode of inheritance of these deletions are not yet clear.


METHODS
Y chromosome deletion mapping and quantitative PCR analysis of the DAZ-gene copy number, supplemented with haplogroup typing in deleted patients, were performed, in combination with clinical assessments in 264 fathers and their sons conceived by assisted reproduction techniques (ART), and in 168 fertile men with normal sperm concentration.


RESULTS
In the ART fathers group, a complete AZFc deletion was detected in 0.4% (1/264). AZFc rearrangements/polymorphisms were found in 6.8% (18/264; 95% CI: 4.4-10.5), which was significantly more frequent (P = 0.021) than in the controls (3/168; 1.8%, 95% CI: 0.6-5.1). All deletions were transmitted to the sons, without any clinical symptoms in early childhood. In the fathers, there was no significant correlation between the DAZ copy number and the severity of spermatogenic failure.


CONCLUSIONS
AZFc rearrangements/polymorphisms are transmitted to sons and may represent a risk factor for decreased testis function and male subfertility, which needs confirmation in further studies in larger cohorts. However, deletions of two DAZ gene copies are compatible with normal spermatogenesis and fertility.
Mau Kai
C
C
University Department of Growth and Reproduction, Rigshospitalet, Section GR-5064, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
Juul
A
A
McElreavey
K
K
Ottesen
A M
AM
Garn
I D
ID
Main
K M
KM
Loft
A
A
Jørgensen
N
N
Skakkebaek
N E
NE
Andersen
A Nyboe
AN
Rajpert-De Meyts
E
E
D000328:Adult; D041322:Chromosomes, Human, Y / Q000235:genetics*; D005640:Follicle Stimulating Hormone / Q000097:blood; D017353:Gene Deletion; D018628:Gene Dosage; D015321:Gene Rearrangement; D056426:Genetic Loci; D005838:Genotype; D006801:Humans; D007248:Infertility, Male / Q000235:genetics*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D027724:Reproductive Techniques, Assisted; D012307:Risk Factors; D029589:Seminal Plasma Proteins / Q000235:genetics*; D013739:Testosterone / Q000097:blood
D029589:Seminal Plasma Proteins; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone