Genetic factors can cause pretesticular, testicular, and post-testicular<unk>  (or oligospermia) and include the following situations: The frequency of chromosomal abnormalities is inversely proportional to the semen count, thus males with<unk>  are at risk to have a 10–15% (other sources citing 15–20% incidence) abnormalities on karyotyping versus about <1 % in the fertile male population. Pretesticular<unk>  may be caused by congential hypopituitarism, Kallmann syndrome, Prader-Willi syndrome and other genetic conditions that lead to GnRH or gonadotropin deficiency. Testicular<unk>  is seen in Klinefelter syndrome(XXY) and the XX male syndrome. In addition, 13% of men with<unk>  have a defective spermatogenesis that is linked to defects of the Y chromosome. Such defects tend to be de novo micro-deletions and affect usually the long arm of the chromosome. A section of the long arm of the Y chromosome has been termed<unk>  Factor (AZF) at Yq11 and subdivided into AZFa, AZFb, AZFc and possibly more subsections. Defects in this area can lead to oligospermia or<unk> , however, a tight genotype-phenotype correlation has not been achieved. Spermatogenesis is defective with gene defects for the androgen receptor. Post-testicular<unk>  can be seen with certain point mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene commonly associated with congenital vas deferens abnormalities. Genetic counselling is indicated for men with genetic causes of<unk> . In terms of reproduction, it needs to be considered if the genetic defect could be transmitted to the offspring. BRD7 BRD7, a transcription regulatory protein, is normally highly expressed in the testis. Absent or reduced expression of BRD7 protein was observed in the testes of<unk>  patients exhibiting spermatogenesis arrest. Homozygous knockout mice BRD7(-/-) are infertile and have higher levels of apoptosis and DNA damage in their germline cells. Gene polymorphisms The human breast cancer susceptibility gene 2 (BRCA2) is employed in DNA repair. A common single nucleotide polymorphism in BRCA2 is associated with idiopathic male infertility with<unk> . Four genes involved in DNA double-strand break repair and chromosome synapsis (TEX11, TEX15, MLH1 and MLH3) have key roles in genomic integrity, meiotic recombination and gametogenesis. Polymorphisms in these genes were tested for associations with male infertility. Single nucleotide polymorphisms in two of these genes (TEX11 and MLH3) were found to be associated with male infertility involving azoospermy or oligospermia.
Azoospermia
Hypospermia
Oligospermia
Asthenozoospermia
Hematospermia
Globozoospermia
Teratospermia
Spermatorrhea