KLINEFELTER SYNDROME |
and will invariably need ART , there |
testes are small ( usually below 5mL ). |
such as breast cancer , extragonadal |
infertility in future generations . If |
Klinefelter syndrome ( 47 , XXY , see figures 6 and 7 ) is the most common sex chromosomal abnormality found |
have been few patients , typically in mosaic cases ( 46 , XY / 47 , XXY ), who can conceive naturally . |
The presence of the extra X chromosome material is thought to be responsible for testicular hyalinisation and |
germ cell tumours , and non-Hodgkin ’ s lymphoma . 14 Thus , vigilance and proper counselling are impor- |
there is full deletion such as in AZF a and b , then it is likely full azoospermia will occur , but if it is AZFc , |
among infertile males ; it has an esti- |
Most patients with Klinefelter syn- |
fibrosis , leading to primary gonadal |
tant with investigations warranted if |
then partial or abnormal spermato- |
mated prevalence of about 5 % in |
drome can exhibit unique pheno- |
failure over time . 13 |
there are suspicious symptoms . |
genesis may be encountered . Given |
severe oligospermia and 10 % in azoospermia . 11 A 47 , XYY male birth occurs in approximately 1:1000 live births , and while these males are often phenotypically normal , they often have small testes and underlying testicular failure . 1 The mosaic karyotype 45 , X / 46 , XY can be found in 4 % of infertile males . 12 |
types , although in many cases these men are largely asymptomatic until they are discovered to be infertile or have hypogonadism . 13 , 14 It is estimated that approximately a quarter of individuals with the condition have no discernible diagnostic features on history or examination . 1 In some affected newborns , features such as a small |
Most patients with Klinefelter syndrome will present with tall stature and long limbs , reflected in a low upper / lower segment ratio . Behavioural difficulties or psychological problems such as immaturity , insecurity and relationship difficulty may be present . 13 , 14 In the long term , men with the condition are more |
Y CHROMOSOME MICRODELETION Microdeletions in the long arm of the Y chromosome containing the azoospermia factor ( AZF ) gene often result in abnormal spermatogenesis . 15 , 16 The prevalence of Y chromosome deletions is estimated to be 1:2000-1:3000 in males and represents the second |
these children are at an increased risk of having phenotypic anomalies associated with sex chromosome mosaicism such as Turner syndrome , genetic counselling is advised for couples during the fertility evaluation . 16
Specific subsections of AZF are critical for spermatogenesis , with AZF deletions found in 8-12 % of
|
Males with karyotypes 47 , XYY , mosaic 45 , X / 46 , XY , 45 , X , and 46 , XX can have variable degrees of fertility . Within the testes of azoospermic |
penis ( micropenis ), hypospadias , cryptorchidism and tiny testes may be present . During puberty , some teens may achieve incomplete puberty and |
likely to develop disorders related to insulin resistance such as dyslipidaemia , fatty liver disease , type 2 diabetes , peripheral vascular disease , |
most common genetic cause of spermatogenetic failure in infertile males after Klinefelter syndrome . 17 These deletions are passed on to 100 % of |
azoospermic males and 3-7 % of oligospermic males . 4 , 15 The Y chromosome locus is divided into three regions , the proximal , middle |
males with Klinefelter syndrome , successful sperm retrieval is possible in up to 50 % of cases . 1 , 3 , 8 While most males with this condition are infertile |
develop gynaecomastia . There is discordant pubertal development with fairly normal development of the penis and pubic hair , although the |
thromboembolic disease and osteopenia / osteoporosis . 14 Some studies also report higher rates of autoimmune disorders and malignancies |
male children born through ART ; therefore testing for Yq deletions allows couples to make an informed choice about the perpetuation of male |
and distal Yq11 , and is designated as AZFa , AZFb , and AZFc , with a fourth AZFd region that overlaps with the AZFb and AZFc regions . 18 |