Klinefelter's Syndrome

Introduction

Klinefelter's syndrome is a genetic disorder that affects about one in five hundred males. It is the most common genetic abnormalities found among humans (Bock, 1993). Men with Klinefelter's syndrome have an extra sex chromosome X instead of the usual male arrangement XY. Sex cells undergo meiosis where the 46 chromosomes in the cell separate, producing two new cells with 23 chromosomes each. Before meiosis is completed, there is an exchange of genetic material between corresponding chromosomes before they separate. In some cases, non-disjunction occurs where the chromosome pairs fail to separate properly. This may result in them moving to the same cell, producing either an egg with two Xs, or a sperm having both an X and a Y chromosome. When a sperm with XY chromosome fertilizes an egg with X chromosome, or a normal Y chromosome sperm fertilizes an egg with XX chromosomes, a male with XXY arrangement is conceived (Bock, 1993).

Affected males are usually taller and have less muscle control and coordination than other boys their age. They have small, firm testes, normal to low plasma testosterone levels and are infertile (Ying). An adult patient with Klinefelter's syndrome will usually be identified only when he is diagnosed with infertility. Most men are not recognized and are never diagnosed in their lifetime (Tyler C, 2004).

Importance of focusing on Klinefelter's Syndrome in Singapore

Singapore's birth rate has been decreasing significantly and it poses a serious concern to the government as it may lead to economic problems and ageing population. Infertility issues partially contribute to a low birth rate. There is an estimated number of 8,707 men in Singapore with Klinefelter's syndrome (Statistics by Country for Klinefelter syndrome). This figure should not be taken lightly as it can potentially result in few hundred less babies yearly.

Current methods to treat Klinefelter's Syndrome

1. Testosterone replacement therapy: Males with Klinefelter's syndrome do not produce enough of the male hormone, testosterone. Testosterone replacement will provide the hormones needed for sexual development and result in a more normal body development. However, this does not address infertility issues.

2. Fertility treatment: Most men with Klinefelter's syndrome are unable to have children as minimal sperm are produced in the testicles. One option that may benefit them is a procedure called intracytoplasmic sperm injection (ICSI), in which a sperm is removed from the testicle and injected directly into the egg (MayoClinic). To date there have been 101 genetic children born to Klinefelter syndrome patients after assisted reproduction techniques (Human Reproduction, 2010). Although studies have shown that there is an increase in infants born through this technique compared to In-Vitro-Fertilisation (ICSI Vs IVF), there may be a higher risk of rare genetic problems and birth defects such as heart and lung conditions