Genetic profile among children with short stature

ABSTRACT

Human growth starts at conception and proceeds through various identifiable developmental stages. The process of growth depends on both genetic and environmental factors that combine to determine an individual's eventual height. Many genes have been identified and their mutations have been shown to be responsible for abnormal growth in humans and animals. Dermatoglyphics can be used to study the participation of genetic factors in diseases while cytogenetic evaluation can be used to detect and study the responsible chromosomes and genes. Fifty-nine short stature patients were included in this study allocated into four groups. Group 1 [Pituitary dwarf] consisted of 26 patients [16 males and 10 females], aged 4-12 years. Group II [Congenital hypothyroidism], included 23 patients [14 males and 9 females], aged 2-12 years. Group III [Down's syndrome] involved 10 patients [5 males and 5 females], aged 3-12 years. A hundred clinically healthy children [50 males and 50 females] of matched age, sex and socioeconomic status represented group IV [control group] aged 2.5-12 years. All patients and control children were subjected to detailed history, family pedigree, thorough clinical examination, anthropometric measurements [14 items, plotted into percentile curves and z-scores], bone age determination by plain x-ray left wrist, IQ assessment using Stanford Binnet test, and chromosomal studies including dermatoglyphics by Ink method, karyotyping and Sister Chromatid Exchange [SCE] by Hockest Giemsa method. Consanguinity was positive in about 50% in groups I and III and about 80% in group II. Patients showed significantly low z-scores for height [mean = -3.67, -3.52, -3.31], sitting height [mean = -3.09, -2.59, -2.06] and arm span [mean = -3.28, -2.45, -2.34] for groups I, II and III respectively. Dermatoglyphic study the finger tip pattern in groups I and II showed a high frequency of radial loops, on the other hand there was a high frequency of ulnar loops in group III. The total ridge count [TRC] was significantly decreased more in group III than group II and insignificantly different in group I when compare to control children, Similarly [atd] angle was significantly increaed [both hands] in groups II and III, while it was insignificantly different in group I in comparison to control children. Total [a-b] ridge count was slower among patients of groups II and III when compared to control but it was significantly higher among patients of group I. The thenar and hypothenar study showed an increase in the pattern in groups I, II and III comparable to control. Interestingly a significant hypothenar whorl pattern in left hand was found in two families of group I. As regards the chromosomal study, both groups I and III showed high frequency of SCE. Also, there was an increase in structural aberrations in both groups [more in group III than group I]. High frequency of consanguinity may be an explanation. On the other hand, the two families showing the special hypothenar whorl pattern also had high frequency SCE. Dermatoglyphic data in this study [Increase in the pattern in thenar and hypothenar areas and increase in [atd] angle and decrease [TRC] could be considered as a diagnostic tool in the assessment of the short child. So, it is recommended to conduct a well-designed nation-wide study of dermatoglyphic, chromosomal and genetic findings for the short child and his family to find out the genetic basis of short stature among Egyptian children