Genetics
Genetic factors can cause  pretesticular, testicular, and post-testicular azoospermia  (or oligospermia)  and include the following situations: The frequency of chromosomal abnormalities is inversely proportional to the semen count, thus males with azoospermia 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 azoospermia may be caused by congential hypopituitarism, Kallmann syndrome, Prader-Willi syndrome and other genetic conditions that lead to GnRH or gonadotropin deficiency. Testicular azoospermia is seen in Klinefelter syndrome (XXY) and the XX male syndrome. In addition, 13% of men with azoospermia 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 Azoospermia Factor (AZF) at Yq11 and subdivided into AZFa, AZFb,  AZFc and possibly more subsections. Defects in this area can lead to oligospermia or azoospermia, however, a tight genotype-phenotype correlation has not been achieved. Spermatogenesis is defective with gene defects for the androgen receptor.Post-testicular azoospermia 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 azoospermia. 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.
History
The disease was first noted by German pathologist Karl Theodor Fahr in 1930. A less common name for the condition is Chavany-Brunhes syndrome and Fritsches syndrome, the former named after Jacques Brunhes, Jean Alfred Émile Chavany, while the later named after R. Fritsche.Fewer than 20 families had been reported in the literature up to 1997. In literature
Fahrs syndrome features in Norwegian Jo Nesbøs crime fiction novel "The Snowman" (the seventh novel in the Harry Hole detective series). See also
Primrose syndrome

References
External links

Fahr Syndrome Images (MedPix)
National Organization for Rare Disorders (NORD)
National Institute on Aging (NIA)
National Institute of Mental Health (NIMH)