A patient can be confirmed as having KS through a genetic test via microarray analysis, FISH analysis, exome sequencing or whole genome sequencing.

But what are the first signs that a baby or child might have KS?

The first signs can be incredibly diverse. Some babies are well and thrive, while others are unusually quiet and passive and a few need to spend time in special care. Babies can vary greatly in birth weight –a normal or high birth weight is often observed. More babies are jaundiced than is typically expected.

In a study of 14 babies by Unique, five seemed fine at birth but concern grew later about their development: they failed to track visually, they failed to watch their mother while feeding or their rate of development was slow. One baby seemed to progress as expected until developing a type of seizure at three months; another repeatedly failed hearing tests. In nine babies, there were signs immediately after birth of something wrong, varying from a weak cry, unusual facial features (twice thought to suggest Down’s syndrome), a small head, hernias in the groin and at the navel, a floppy larynx, heart problems, cataracts, seizures and feeding difficulties. Early feeding difficulties are common and so is silent reflux – where milk returns from the stomach up the food passage, however, most babies with feeding difficulties only need help (tube feeding) for a short time. Although a low muscle tone (floppiness) is usually characteristic of newborn babies with KS, this may not be obvious: in four babies, no floppiness was observed.

Apart from these common difficulties of newborns, most babies with the KS have reasonable Apgar scores (a measure of well-being at birth, scored from 0-10) and are quite well after birth and are able to go home after delivery at the normal time.

Many cases have been reported where a person has been diagnosed in their mid-teens or even in adulthood. This trend is expected to continue as undiagnosed patients are re-checked or advances in the science of genetic testing are made.