Diagnostic algorithm of Down syndrome by minor physical anomaly.

Abstract

Background:Down syndrome, most common chromosomal abnormality leading to intellectual disability is being diagnosed by Karyotyping. Due to cost constraints, parents couldn’t afford to do Karyotyping which causes delay in individual and family interventions.Introduction:Down syndrome has characteristic morphological features. The minor physical anomaly (MPA) are insults which occur in utero during embryonic development mostly in first and early second trimester and persists throughout life.Material and Methods:70 karyotyping confirmed cases of Down syndrome (DS), 70 other causes of intellectual disabilities (Other ID) and 70 age matched normal children and adolescents (Average) have been incorporated in the study. The Modified Waldrop's scale (Ismail's 41 item scale) have been applied. Demographic comparison and Decision tree algorithm approach have been analysed by SPSS 25 version.Results and Discussion:The paternal age of childbirth, maternal age of childbirth, maternal age of marriage (P < 0.001), income (P = 0.026) variables are statistically significant in Down's syndrome group in comparison to other two groups whereas age and birth order are not statistically significant. DS group has more MPA (m = 17.04, SD = 5.462), than other ID (m = 5.93, SD = 2.628) and Average group (m = 1.59, SD = 1.378). Big sandal gap, high arched palate and epicanthus are most common three minor anomalies found in Down syndrome. Region wise scoring shows high significance (P < 0.001) in Global head, eyes, ears, mouth, hands and feet in Down syndrome group. The four anomalies; epicanthus, telecanthus, high-arched palate, and curved fifth finger) thus can be grouped as differentiating anomalies. When clinodactyly (item 27) and high arched palate (item 21) are present together or epicanthus (item 08) and telecanthus (item 09) present together sensitivity of diagnosing the case as Down syndrome is 0.945 with negative predictive value 0.979.Conclusion:The simian crease which is being considered as common physical anomaly is not specific for Down syndrome. The large scale study is required to extrapolate the above findings but surely it opens new avenue of research.