RESUMO
The present study aimed to investigate the genetic risk factors among the Egyptian Down syndrome [DS] cases and to study the association between the parental body physique and growth pattern of DS. Evaluation of sibs' growth was also done. The study included 75 Egyptian DS children [42 boys and 33 girls] ranged in age from one month to 13.25 years. Pedigree analysis, thyroid profile, cardiac evaluation and chromosomal study were performed. For every case anthropometric parameters were taken including weight, height and head circumference. Body mass index [BMI] was calculated. Anthropometric parameters of 73 mothers, 33 fathers and 16 sibs were also taken. Bone age evaluation and prediction of adult height were done for 29 cases. Target genetic height was estimated. According to parental BMI cases were divided into two groups [DS children with obese and non-obese parents]. The results showed positive consanguinity in 28.36% of cases, with first degree consanguineous patients in 10.45%. Down syndrome patients with congenital heart disease [CHD] had higher consanguinity rate compared to cases without CHD. Positive family history of DS was seen in 1.54% and of other genetic disorders in 18.46% of cases. Mean maternal and parental ages were 32.9 and 37.2 years, respectively. Birth order showed no significant difference between first and late born DS children. Trisomy 21 was found in 88.6% of cases, translocation in 9.0% and mosaicism in 2.2%. Mean predicted adult heights for female and male cases were 148.3 and 156.11 cm, respectively. Reduced mid parental height was associated with abnormally decreased target genetic height of DS children. Short stature was noticed in 44.16%, microcephaly in 62.16% and obesity in 16% of cases. Tendency for obesity was increased with advantage of age. Significant positive correlations were observed between maternal weight and both the patient's weight and BMI and between maternal height and the patient's height. Obese and short DS cases had mothers characterized by obesity and short stature. Short stature was found in 18.75% of DS siblings