Idiopathic short stature

Puberty and pubertal growth dynamics in children with idiopathic short stature

OBJECTIVE

As the prognosis for final height is unfavorable for children with idiopathic short stature (ISS), we studied the pubertal growth dynamics in these children, which is a determinant factor in final height.

SUBJECTS/METHODS

In a retrospective cohort study, we analyzed the pubertal period, age of puberty and peripubertal growth in 50 children with ISS.

RESULTS

The onset of puberty occurred later. Growth rate tended to become increasingly subnormal in the prepubertal period and height was -2.45 SD at puberty onset. Growth reaccelerated at this point, which tended to correct the deviation from the mean height, but it was insufficient to obtain a normal final height.

CONCLUSIONS

The dynamics of growth in children with ISS showed a distinct pattern in the prepubertal and pubertal periods and puberty is significantly delayed in this population. These patterns could explain the unfavorable prognosis for children with ISS.

Prevalence of celiac disease in Iranian children with idiopathic short stature

AIM: To determine the prevalence of celiac disease (CD) in children with idiopathic short stature (ISS) and the diagnostic value of immunoglobulin (Ig) A G antigliadin antibodies (AGA) and transglutaminase (TTG) antibodies for CD.

METHODS: A total of 104 children (49 male, 55 female) with ISS without a specific etiology were studied. Extensive endocrine investigations had shown no abnormalities in any subject. Anthropometric parameters and IgA AGA and IgA TTG antibodies were evaluated in this study group. These antibodies were measured by enzyme-linked immunosorbent assay. All patients were referred for an endoscopic intestinal biopsy. The biopsy samples were classified according to revised Marsh criteria (UEGW 2001).

RESULTS: We detected positive IgA TTG antibodies in 36 and IgA AGA in 35 of these patients. Thirty one IgA TTG antibody positive and 28 IgA AGA positive subjects showed histological abnormalities compatible with celiac disease (33.6%). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value for IgA AGA were found to be 80%, 88.4%, 77.8% and 89.7%, respectively. Sensitivity, specificity and PPV for IgA TTG antibodies were 88.6%, 94.2% and 88.6%, respectively.

CONCLUSION: We conclude that the prevalence of celiac disease is high in patients with ISS and it is important to test all children with ISS for celiac disease by measuring serologic markers and performing an intestinal biopsy.

Evidence for involvement of the vitamin D receptor gene in idiopathic short stature via a genome-wide linkage study and subsequent association studies

Stature is a highly heritable trait under both polygenic and major gene control. We aimed to identify genetic regions linked to idiopathic short stature (ISS) in childhood, through a whole genome scan in 92 families each with two affected children with ISS, including constitutional delay of growth and puberty and familial short stature. Linkage analysis was performed for ISS, height and bone age retardation. Chromosome 12q11 showed significant evidence of linkage to ISS and height (maximum non-parametric multipoint LOD scores 3.18 and 2.31 at 55-58 cM, between D12S1301 and D12S1048), especially in sister-sister pairs (LOD score of 1.9 for ISS in 22 pairs). These traits were also linked to chromosomes 1q12 and 2q36. The region on chromosome 12q11 had previously shown significant linkage to adult stature in several genome scans and harbors the vitamin D receptor gene, which has been associated with variation in height. A single nucleotide polymorphism (SNP) (rs10735810, FokI), which leads to a functionally relevant alteration at the protein level, showed preferential transmission of the transcriptionally more active G-allele to affected children (P=0.04) and seems to be responsible for the observed linkage (P=0.05, GIST test). Bone age retardation showed moderate linkage to chromosomes 19p11-q11 and 7p14 (LOD scores 1.69 at 57 cM and 1.42 at 50 cM), but there was no clear overlap with linkage regions for stature. In conclusion, we identified significant linkage, which might be due to a functional SNP in the vitamin D receptor (VDR) gene and could be responsible for up to 34% of ISS cases in the population.

Children with idiopathic short stature are poor eaters and have decreased body mass index

OBJECTIVE

In children with idiopathic short stature (ISS), studies investigating body mass index (BMI) or parameters of satiety regulation are scarce, and studies analyzing eating behavior are lacking.

METHODS

We recruited 214 children (123 index cases and 91 siblings) with ISS from 123 families. Affected children had to have a body height <5th percentile, or, in the case of siblings, the body height of 1 child had to be <5th percentile and the other <15th percentile. Medical histories were recorded by using structured and standardized interviews. Eating behavior was assessed by using the Child Eating Behavior Questionnaire. Percent energy intake as fat was assessed by using the Leeds Food Frequency Questionnaire. Endocrine markers of body weight regulation (leptin, ghrelin) were determined in serum.

RESULTS

Compared with population norms, BMI was significantly lower (mean: -0.33 standard deviation score). Furthermore, there was decreased food responsiveness (mean Child Eating Behavior Questionnaire score: 1.9; population mean: 2.4), reduced enjoyment of food (3.2 vs 3.9), emotional undereating (2.6 vs 3.0), lower desire to drink (2.0 vs 2.8), and increased fussiness over food (3.2 vs 2.9). When the sample was subdivided into the 2 groups of "good" and "poor" eaters according to the mothers' assessment of the current eating behavior, reduction in BMI as well as the behavioral characteristics already delineated in the total sample were found to be even more consistent in the subgroup of poor eaters. In the total sample of our children, as well as in both subgroups, serum leptin (adjusted for gender, BMI, and Tanner stage) was found to be moderately raised but did not differ between poor and good eaters. Total serum ghrelin was not different between poor and good eaters.

CONCLUSIONS

Our clinical, behavioral, and endocrinologic findings in patients with ISS point to an altered eating behavior that possibly contributes to their short stature.