Causes of short stature in Pakistani children found at an Endocrine Center

Use of whole exome sequencing for identification of genetic variants related to Growth Hormone Deficiency and Short Stature: A Family-Based Study

Objective

Genetic polymorphisms in genes involved in growth process and Vitamin-D metabolism form a significant etiology behind growth hormone deficiency and short stature. The aim of this study was to explore for known and unknown genes and variants related to growth hormone and short stature in a family based study using whole exome sequencing (WES).

Method

This family-based study included a family with members diagnosed with growth hormone deficiency, short stature and Vitamin-D deficiency (four boys affected and four boys non-affected). The participants were recruited from King Abdulaziz University Hospital (Jeddah, Saudi Arabia) and referred to King Fahad Centre for Medical Research (Jeddah, Saudi Arabia from April 2022 to June 2022. The consanguineous parents and one of the affected boys (aged 16 years old) underwent WES.

Results

Several variants in RNPC3, ACAN, GC, VDR and LRP2 were identified in index cases but not in controls. Novel frameshift and splice region variants in RNPC3 (c.358dupA, p.Arg120fs) were detected. Other missense variants were also observed including variants in ACAN (c.2591C>T, c.2789G>T, c.2815T>A, c.4207A>G, c.4523A>C and c.7119C>G), GC (rs4588 and rs7041) and LRP2 (rs2075252 and rs1991517). A start loss variant in VDR (rs2228570) with high impact was also observed.

Conclusions

Our findings suggest a potential association of these variants with growth hormone deficiency and short stature. In this study, novel pathogenic variants in RNPC3 were revealed as well as other variants in ACAN and in genes related to Vitamin-D metabolism (GC, VDR and LRP2) that some or all might be associated with growth hormone deficiency. Further large-scale studies are required to address the association of these variants with growth hormone deficiency and its subsequent short stature.

Analysis of Vitamin D Components in Serum of Minors by UHPLC-MS/MS

Serum 25-hydroxyvitamin D [25(OH)D] concentration represents the body's reserves of vitamin D, which is mostly used by clinicians to evaluate the storage status of vitamin D in the body. The present study aimed to investigate the serum vitamin D components in different health status of minors to correctly evaluate the vitamin D storage in vivo. A total of 2,270 minors were included in the study, which was divided into healthy group (1,204 cases) and disease group (1,066 cases, including 270 short stature, 433 respiratory infections, 175 malnutrition and 188 tic disorder subjects). The levels of 25-hydroxyvitamin D₂ [25(OH)D₂] and 25-hydroxyvitamin D₃ [25(OH)D₃] were measured by UHPLC-MS/MS in all subjects, and the 25(OH)D₃ activity equivalents [25(OH)D₃-AE] and 25(OH)D were calculated. In addition, the 3-epi-25-hydroxyvitamin D₃ [3-epi-25(OH)D₃] concentrations of 278 subjects (including 147 healthy and 131 disease subjects) were measured by random sampling. 25(OH)D₂, 25(OH)D₃, 25(OH)D and 25(OH)D₃-AE levels in disease group were significantly lower than those in healthy group (p<0.001). According to the level of 25(OH)D, the sufficiency of vitamin D [25(OH)D≥30 ng/mL] was 65.4% in healthy group and 50.5% in disease group. When the 25(OH)D₂ activity was converted into 25(OH)D₃-AE, 53.2% of the patients in the healthy group had sufficiency vitamin D, and 39.1% in the disease group. The 3-epi-25(OH)D₃ level in the disease group was significantly lower than that in the healthy group (p<0.001). Not only the 25(OH)D, but also the both of 25(OH)D₂ and 25(OH)D₃ levels may overestimate the vitamin D status in subjects. For accurate evaluation, at least the serum levels of 25(OH)D₂, 25(OH)D₃ and 3-epi-25(OH)D₃ should be determined simultaneously.

Alfacalcidol improves the growth velocity in children with vitamin D deficiency/insufficiency: A single center retrospective cohort study

OBJECTIVES

To investigate the growth velocity-improving effects of vitamin D replacement therapy in pediatric patients diagnosed with vitamin D deficiency and insufficiency.

STUDY DESIGN

A retrospective cohort study was conducted in 34 pediatric patients diagnosed with vitamin D deficiency/insufficiency. Based on the clinical findings, the subjects were divided into two groups: a bowed leg (BL) group and a non-bowed leg (non-BL) group. After the initiation of alfacalcidol, the standard deviation score (SDS) of their heights, weights and growth velocities in each group were monitored.

RESULTS

The median age at the first visit was significantly lesser in the BL group (1.58 years old [interquartile range (IQR): 1.33, 2.17]) than that in the non-BL group (3.00 years old [IQR: 2.33, 3.67]). On the contrary, the SDS for height was significantly lower in the non-BL group (-2.27 [IQR: -2.63, -1.94]) than that in the BL group (-1.37 [IQR: -1.91, -1.07]). One-year treatment with alfacalcidol showed significant improvements in both height SDSs and growth velocity SDSs not only in the BL group but also in the non-BL group.

CONCLUSIONS

The current study revealed that vitamin D replacement therapy improved the growth rate in children with vitamin D deficiency/insufficiency, regardless of the presence of BL. This study emphasizes the importance of assessing the vitamin D status in children with poor growth rates and suggests that alfacalcidol could be a valid option for the treatment of short stature.

Characteristics and etiologies of short stature in children: Experience of an endocrine clinic in a Tunisian tertiary care hospital

Background

Short stature is a common reason for referral to pediatric endocrinology clinics. It may be a manifestation of a pathological condition requiring early treatment. The aim of this study was to describe the characteristics and etiologies of short stature among children referred to the pediatric endocrinology clinic of the main pediatric tertiary care center in Tunisia.

Methods

Retrospective and descriptive study in the endocrinology unit of children referred for short stature between January 2012 and December 2016. Data on the patients' medical history, physical findings, laboratory tests, bone age and chromosomal analysis were collected.

Results

470 children (266 males and 204 females) were referred during that period. 214 (45.5%) had normal height, and 80.8% of them were referred by general practitioners. The other 256 children (54.5%) had a confirmed short stature (mean age :7.2 years, mean height: -2.77 SDS). Endocrinological causes were the most common(43% GHD, 4% hypothyroidism) followed by intrauterine growth retardation IUGR (24%), genetic syndromes (8.4%), chronic pediatric diseases (7.8%), skeletal dysplasia (6.2%), normal variant of short stature (5%), and psychosocial deprivation (1.2%). Among non-endocrine causes, Turner syndrome was the most common genetic syndrome (4.4%), achondroplasia the main skeletal dysplasia (4%) and celiac disease the main chronic disease (3.4%).

Conclusions

ST is largely overestimated in our country. Therefore, it is important to insist on adequate measurement and analysis of growth parameters to avoid unnecessary investigations. GHD and IUGR were the most common causes. Celiac disease, though frequent in Tunisia, is not a common cause of short stature.

Vitamin D Deficiency in the Gulf Cooperation Council: Exploring the Triad of Genetic Predisposition, the Gut Microbiome and the Immune System

Vitamin D is a fat soluble secosteroid that is primarily synthesized in the skin upon exposure to Ultraviolet B (UVB) sun rays. Vitamin D is essential for the growth and development of bones and helps in reducing inflammation by strengthening muscles and the immune system. Despite the endless supply of sunlight in the Gulf Cooperation Council (GCC) countries which includes United Arab Emirates, Qatar, Kuwait, Bahrain, Saudi Arabia, and Oman, Vitamin D deficiency in the (GCC) general population at various age groups remains alarmingly high. In parallel runs the increasing prevalence of acute and chronic illnesses including, autoimmune diseases, cancer, type 1 diabetes mellitus, cardiovascular disease and Inflammatory bowel disease in the adult as well as the pediatric population of these countries. The exact association between Vitamin D deficiency and chronic disease conditions remains unclear; however, studies have focused on the mechanism of Vitamin D regulation by assessing the role of the Vitamin D associated genes/proteins such as VDR (Vitamin D receptor), VDBP (Vitamin D Binding protein), CYP27B1 as these are integral parts of the Vitamin D signaling pathway. VDR is known to regulate the expression of more than 200 genes across a wide array of tissues in the human body and may play a role in controlling the Vitamin D levels. Moreover, reduced Vitamin D level and downregulation of VDR have been linked to gut dysbiosis, highlighting an intriguing role for the gut microbiome in the Vitamin D metabolism. However, this role is not fully described yet. In this review, we aim to expand our understanding of the causes of Vitamin D deficiency in the GCC countries and explore the potential relationship between the genetic predisposition, Vitamin D levels, immune system and the gut microbiome composition. Trying to unravel this complex interaction may aid in understanding the mechanism by which Vitamin D contributes to various disease conditions and will pave the way toward new therapeutics treatments for Vitamin D deficiency and its associated outcomes.