  Background: Advanced biological techniques have helped produce more
insightful findings on the genetic etiology of infertility that may lead to
better management of the condition. This review provides an update on genes
predisposing to syndromic and nonsyndromic infertility.
  Main body: The review identified 65 genes linked with infertility and
infertility-related disorders. These genes regulate fertility. However,
mutational loss of the functions of the genes predisposes to infertility.
Twenty-three (23) genes representing 35% were linked with syndromic
infertility, while 42 genes (65%) cause nonsyndromic infertility. Of the 42
nonsyndromic genes, 26 predispose to spermatogenic failure and sperm
morphological abnormalities, 11 cause ovarian failures, and 5 cause sex
reversal and puberty delay. Overall, 31 genes (48%) predispose to male
infertility, 15 genes (23%) cause female infertility, and 19 genes (29%)
predispose to both. The common feature of male infertility was spermatogenic
failure and sperm morphology abnormalities, while ovarian failure has been the
most frequently reported among infertile females. The mechanisms leading to
these pathologies are gene-specific, which, if targeted in the affected, may
lead to improved treatment.
  Conclusions: Mutational loss of the functions of some genes involved in the
development and maintenance of fertility may predispose to syndromic or
nonsyndromic infertility via gene-specific mechanisms. A treatment procedure
that targets the affected gene(s) in individuals expressing infertility may
lead to improved treatment.
