<prompt> Increased nuchal fold thickness is a feature of ?Paul-Bunnel syndromeDe-pan syndromeDowns syndromeCri-duchat syndrome  <response>: Ans. is c i.e., Downs Syndrome Nuchal fold thickness is increased in Down syndrome. This feature is used in suspecting the diagnosis of Downs syndrome prenataly. Downs syndrome o Downs syndrome is due to trisomy 21. o Downs syndrome is the most common trisomy. o In this condition, extragenetic materia causes delay in the way a child develops and often leads to mental retardation. o In Downs syndrome the child gets on extra chromosome, he has total of 47 chromosome instead of 46 chromosome. o This is the extra genetic material that causes the physical and cognitive delays associated with Downs syndrome. o There is a well recognized association with advanced maternal age, the risk considerably increases in women 35 years of age. o Advanced paternal age has no effect. 