This paper presents variability in both age of onset, clinical picture and neuroimaging findings even in the same family, comprising new congenital abnormalities associated with AGS and subsequently expanding the spectrum of heterogeneity. The observation of familial cases and both affected males and females emphasized the major role of the single gene inheritance.

A study established growth and growth velocity curves for weight, length and head circumference in 350 Egyptian Down syndrome children [188 males and 162 females] from 0-36 months. Down syndrome children had poorer growth variables than normal healthy children through the first 3 years of life. Down syndrome children with associated congenital heart disease [90 cases] had significantly lower weight, especially in girls, compared with those without heart disease. In the first 2 years, growth velocity for weight and head circumference were higher in Down syndrome females than males, while growth velocity for length was higher in males. Down syndrome boys had slightly higher velocity of length than normal children in the first 3 years of life