Increased nuchal fold thickness is a feature of –
Nuchal fold thickness is increased in Down syndrome. This feature is used in suspecting the diagnosis of Down's syndrome prenataly.
Down's syndrome 

Down's syndrome is due to trisomy 21.
Down's syndrome is the most common trisomy.
In this condition, extra genetic material causes a delay in the way a child develops and often leads to mental retardation.
In Down's syndrome the child gets on the extra chromosome, he has a total of 47 chromosomes instead of 46 chromosomes.
This is the extra genetic material that causes the physical and cognitive delays associated with Down's syndrome.
There is a well-recognized association with advanced maternal age, the risk considerably increases in women > 35 years of age.
Advanced paternal age has no effect.
Paul–Bunnel syndrome
De–pan syndrome
Down's syndrome
Cri–duchat syndrome