Objective:This study aimed to integrate the existing updated reference standards for the growth of Turkish infants and children and to compare these values with World Health Organization (WHO) reference data, data from some European countries, and also with previous local data. Weight, height, and head circumference measurements were obtained on 2,391 boys and 2,102 girls who were regular attenders of a well child clinic and on 1,100 boys and 1,020 girls attending schools in relatively well-off districts in İstanbul. Mean number of measurements per child was 8.2±3.6 in the age group 0-5 years and 5.5±3.3 in the age group 6-18 years. All children were from well-to-do families and all were healthy. All measurements with the exception of measurements at birth, which were based on reported values, were done by trained personnel.Methods:The LMS method was used in the analyses and in the construction of the percentile charts. There is an increase in weight for age and body mass index values for age starting in prepubertal ages, indicating an increasing trend for obesity.Results: Compared to WHO reference data, weight and height values in Turkish children were slightly higher in infants and in children younger than 5 years, while they showed similarity to those reported for children from Norway and Belgium. Head circumference values, which were slightly higher than the WHO references in the first 5 years, were comparable to the data on Belgian and Norwegian children in the first 9 years of life. At older ages, Turkish children showed higher values for head circumference.Conclusion:The relatively larger head circumference values were interpreted to reflect a genetic characteristic.

Heterozygous coding mutations in the INS gene that encodes preproinsulin were recently shown to be an important cause of permanent neonatal diabetes. These dominantly acting mutations prevent normal folding of proinsulin, which leads to beta-cell death through endoplasmic reticulum stress and apoptosis. We now report 10 different recessive INS mutations in 15 probands with neonatal diabetes. Functional studies showed that recessive mutations resulted in diabetes because of decreased insulin biosynthesis through distinct mechanisms, including gene deletion, lack of the translation initiation signal, and altered mRNA stability because of the disruption of a polyadenylation signal. A subset of recessive mutations caused abnormal INS transcription, including the deletion of the C1 and E1 cis regulatory elements, or three different single base-pair substitutions in a CC dinucleotide sequence located between E1 and A1 elements. In keeping with an earlier and more severe beta-cell defect, patients with recessive INS mutations had a lower birth weight (−3.2 SD score vs. −2.0 SD score) and were diagnosed earlier (median 1 week vs. 10 weeks) compared to those with dominant INS mutations. Mutations in the insulin gene can therefore result in neonatal diabetes as a result of two contrasting pathogenic mechanisms. Moreover, the recessively inherited mutations provide a genetic demonstration of the essential role of multiple sequence elements that regulate the biosynthesis of insulin in man. (8-12). In contrast, abnormalities in chromosome 6q24 are the most common cause of TNDM (13), followed by mutations in the KCNJ11 and ABCC8 genes (14). Despite these advances, the etiology of neonatal diabetes is still not known in at least 30% of patients with PNDM, suggesting other genetic causes are still to be found (9).Insulin is secreted from islet beta cells of the pancreas. Insufficient secretion of insulin results in hyperglycemia and diabetes, whereas excessive secretion results in hypoglycemia. Insulin biosynthesis and secretion are therefore tightly regulated to maintain blood glucose levels within a narrow physiological range. Extensive studies have dissected an array of cis sequence elements in the INS promoter region and their cognate DNA binding factors, which together ensure the cellular specificity and rate of INS transcription (15)(16)(17)(18)(19)(20)(21)(22). In addition, insulin biosynthesis is strongly dependent on posttranscriptional regulatory mechanisms, including the modulation of translation and stability (23-25). The latter is largely mediated through sequences located in the untranslated regions of INS transcripts (26-28).

These results indicate that height growth in Turkish school-age children of high socio-economic level conforms to the updated growth data on US children. The data also show a secular upward trend in Turkey. Weight-for-age values indicate an increase in obesity. The results also point to the value of collecting and evaluating local growth data periodically.

This study presents data and curves for body mass index values in healthy Turkish children aged 6 to 18 y. The values are in compliance with those of Western countries.