Genetics of pubertal delay.

The timing of pubertal development is strongly influenced by the genetic background, and clinical presentations of delayed puberty are often found within families with clear patterns of inheritance. The discovery of the underlying genetic regulators of such conditions, in recent years through next generation sequencing, has advanced the understanding of the pathogenesis of disorders of pubertal timing and the potential for genetic testing to assist diagnosis for patients with these conditions. This review covers the significant advances in the understanding of the biological mechanisms of delayed puberty that have occurred in the last two decades.

Prevalence and risk factors for vitamin D insufficiency in 6-12-month-old infants: a cross-sectional study in Southern Thailand.

BACKGROUND: Vitamin D is an essential micronutrient for bone mineralization and bone growth in children. There have been few studies to date of vitamin D status in infants aged 6-12 months in Southeast Asian countries. AIM: To examine the prevalence of vitamin D insufficiency (VDI, including vitamin D deficiency) in healthy infants and the risk factors for VDI in southern Thailand. METHODS: A cross-sectional study was carried out in 120 healthy infants aged 6-12 months and their mothers. Blood samples were obtained for measurement of serum calcium, phosphate, alkaline phosphatase, albumin, parathyroid hormone and 25-hydroxyvitamin D (25OHD) levels. The mothers were interviewed for their infants feeding intake, sunlight exposure, type of dress, and sunscreen use. Chi-square and t-test were used to compare between groups for categorical and continuous variables, respectively. Pearson correlation was used to identify the relationship between serum levels of 25OHD of the infants and other biochemical variables of the infants and serum levels of maternal 25OHD. Logistic regression analysis was used to identify the factors associated with vitamin D status. RESULTS: The prevalence of VDI in our study infants was high at 28.3%, all of whom were mainly breastfed infants. Subgroup analysis of the mainly breastfed infants found that the risk factors for VDI were maternal VDI and a short duration of sunlight exposure. The serum 25OHD levels of the mainly breastfed infants were significantly positively correlated with the maternal serum 25OHD levels (r = 0.49, p-value < 0.01) and with sunlight exposure duration (r = 0.40, p-value < 0.01). CONCLUSIONS: The prevalence of VDI was high in 6-12-month-old infants, particularly those who were mainly breastfed from VDI mothers, and who had short durations of sunlight exposure. As breast milk contains adequate amounts of most important vitamins and growth factors, breastfeeding is still encouraged for infants with 400 IU vitamin D daily supplementation to prevent VDI.

Optimal final adult height achieved by low-dose recombinant human growth hormone therapy.

Background: Thailand has been administering the recombinant human growth hormone (rhGH) treatment for >20 years. Due to limited resources being available, efforts have been directed toward utilizing rhGH at the lowest feasible dose. However, there is currently a lack of evidence in terms of the efficacy and outcomes. Objective: To evaluate the auxological outcomes of growth hormone (GH) treatment and the GH secretion ability after reaching final adult height (FAH) and discontinuing rhGH. Methods: Data of 40 patients were retrospectively reviewed. The clinical characteristics, auxological data, and results of biochemical and endocrine investigations before and during rhGH treatment were evaluated. In addition, GH retesting was performed in 24 patients using the insulin tolerance test. Results: Twenty patients (50%) had complete growth hormone deficiency (GHD), defined as peak stimulated GH level <5 ng/mL, and the remaining patients had partial GHD. Most patients were male (n = 25, 62.5%). The mean age at which rhGH was initiated was 8.9 years. Patients with partial GHD received a higher dose of rhGH than those with complete GHD (30.9 µg/kg/d vs. 26.2 µg/kg/d, P = 0.02). Patients with complete and partial GHD reached FAH at height standard deviation scores (SDSs) of -0.65 and -1.47, respectively. The factors associated with obtaining a good clinical response in terms of height gain included peak-stimulated GH level, age of puberty, and age of discontinuing rhGH. After completing the rhGH treatment, 13 of the 24 patients showed normal GH secretion. Patients with multiple pituitary hormone deficiency (MPHD) were likely to have persistent GHD through adulthood (n = 8, 88.9%). Conclusion: This study has demonstrated that the use of low-dose rhGH could result in healthy populations achieving optimal FAHs. Patients with MPHD might not require retesting as they were likely to have persistent GHD. The results obtained in this research highlight the benefits of the treatment. This treatment can be applied in resource-limited countries.

Vitamin D status in non-pregnant women of reproductive age: a study in Southern Thailand.

Vitamin D inadequacy is a global problem in all age groups. Although there are various studies of vitamin D status in pregnant women in Southeast Asia, to date there are few studies from Southeast Asia examining vitamin D status in non-pregnant women of reproductive age. To examine the prevalence of vitamin D insufficiency (VDI) in healthy non-pregnant women of reproductive age in Southern Thailand, 120 healthy non-pregnant women aged 18-42 years were enrolled. Demographic and lifestyle data relevant to vitamin D assessment (sunlight exposure, nutritional intake, type of dress, sunscreen use) and biochemical studies (serum 25-hydroxyvitamin D or 25OHD, parathyroid hormone, calcium, phosphate) were obtained. VDI was classified as serum 25OHD < 20 ng/mL. The average serum 25OHD level was 23.1 ± 6.0 ng/mL. The overall prevalence of VDI was 34.1%. The average dietary intake of calcium, phosphorus and vitamin D and the average duration of sunlight exposure per week were not significantly different between the VDI women and the vitamin D sufficient (VDS) women. Logistic regression analysis found that the significant risk factors for VDI were greater body mass index and higher family income (p-values 0.01 and 0.02, respectively). The prevalence of VDI in non-pregnant women was high at 34%. As the dietary sources of vitamin D are limited and cutaneous vitamin D synthesis is limited by avoidance of sunlight exposure, vitamin D fortification in common daily foods would be an alternative option to reach the recommended vitamin D intake generally of at least 800 IU/day.

Genetic evaluation supports differential diagnosis in adolescent patients with delayed puberty.

CONTEXT: Pubertal delay can be the clinical presentation of both idiopathic hypogonadotropic hypogonadism (IHH) and self-limited delayed puberty (SLDP). Distinction between these conditions is a common but important diagnostic challenge in adolescents. OBJECTIVE: To assess whether gene panel testing can assist with clinical differential diagnosis and to allow accurate and timely management of delayed puberty patients. DESIGN: Retrospective study. METHODS: Patients presenting with delayed puberty to UK Paediatric services, followed up to final diagnosis, were included. Whole-exome sequencing was analysed using a virtual panel of genes previously reported to cause either IHH or SLDP to identify rarely predicted deleterious variants. Deleterious variants were verified by in silico prediction tools. The correlation between clinical and genotype diagnosis was analysed. RESULTS: Forty-six patients were included, 54% with a final clinical diagnosis of SLDP and 46% with IHH. Red flags signs of IHH were present in only three patients. Fifteen predicted deleterious variants in 12 genes were identified in 33% of the cohort, with most inherited in a heterozygous manner. A fair correlation between final clinical diagnosis and genotypic diagnosis was found. Panel testing was able to confirm a diagnosis of IHH in patients with pubertal delay. Genetic analysis identified three patients with IHH that had been previously diagnosed as SLDP. CONCLUSION: This study supports the use of targeted exome sequencing in the clinical setting to aid the differential diagnosis between IHH and SLDP in adolescents presenting with pubertal delay. Genetic evaluation thus facilitates earlier and more precise diagnosis, allowing clinicians to direct treatment appropriately.

Whole exome sequencing identifies deleterious rare variants in CCDC141 in familial self-limited delayed puberty.

Developmental abnormalities of the gonadotropin-releasing hormone (GnRH) neuronal network result in a range of conditions from idiopathic hypogonadotropic hypogonadism to self-limited delayed puberty. We aimed to discover important underlying regulators of self-limited delayed puberty through interrogation of GnRH pathways. Whole exome sequencing (WES) data consisting of 193 individuals, from 100 families with self-limited delayed puberty, was analysed using a virtual panel of genes related to GnRH development and function (n = 12). Five rare predicted deleterious variants in Coiled-Coil Domain Containing 141 (CCDC141) were identified in 21 individuals from 6 families (6% of the tested cohort). Homology modeling predicted all five variants to be deleterious. CCDC141 mutant proteins showed atypical subcellular localization associated with abnormal distribution of acetylated tubulin, and expression of mutants resulted in a significantly delayed cell migration, demonstrated in transfected HEK293 cells. These data identify mutations in CCDC141 as a frequent finding in patients with self-limited delayed puberty. The mis-localization of acetylated tubulin and reduced cell migration seen with mutant CCDC141 suggests a role of the CCDC141-microtubule axis in GnRH neuronal migration, with heterozygous defects potentially impacting the timing of puberty.

The etiologies and incidences of congenital hypothyroidism before and after neonatal TSH screening program implementation: a study in southern Thailand.

BACKGROUND: Congenital hypothyroidism (CH) is one of the common causes of intellectual disability which can be prevented by early detection of an elevated thyroid stimulating hormone (TSH) level in the newborn and by treatment with thyroxine. In Thailand, neonatal TSH screening was implemented nationwide in 2005. The objective of the study was to determine the etiologies and the estimated incidences of CH in southern Thailand before and after the implementation of a neonatal TSH screening program in 2005. METHODS: The medical records of pediatric patients who were diagnosed with primary CH at Songklanagarind Hospital during 1995-2013 were retrospectively reviewed. The study was divided into two time periods: study period 1 (SP1) (1995-2004) and study period 2 (SP2) (2005-2013), the time before and after TSH program implementation. RESULTS: The most common form of CH during SP1 was overt permanent CH (66%), mostly caused by athyreosis or ectopic thyroid. In SP2, the most common form of CH was mild permanent CH (39%) (mostly due to dyshormonogenesis), followed by overt CH (32%) and transient CH (29%). The overall annual estimated incidence of CH per 10,000 live births in Songkhla Province was 1.69 (1:5021) in SP1, increasing to 4.77 (1:2238) in SP2; in all 14 provinces in southern Thailand, the estimated incidence was 1.24 (1:8094) in SP1 and 2.33 (1:4274) in SP2. CONCLUSIONS: Neonatal TSH screening has a significant impact on the increased detection of the mild form of permanent and transient CH cases, which may be important for the prevention of brain damage from less severe CH although this remains to be documented.

Etiologies of short stature in a pediatric endocrine clinic in Southern Thailand.

BACKGROUND: Short stature is one of the common disorders referred for investigation of an endocrine disorder. The etiologies of short stature vary and are commonly grouped into pathological and non-pathological disorders. The objective of the study was to determine the etiologies and describe the characteristics of short stature patients who attended the Pediatric Endocrinology Clinic and to compare factors between normal variant short stature (NVSS) and growth hormone deficiency (GHD). METHODS: This was a retrospective review of 572 patients referred for evaluation of short stature between January 2004 and December 2015. Short stature was defined as height below -2 standard deviation score (SDS) by gender and age based on population data of Thai children. RESULTS: In total, 521 patients were identified as having short stature. NVSS was the most common etiology (44.9%) and pathological short stature was found in 35.3% of the cases, of which 21.2% had GHD. The median age at presentation of NVSS patients was 8.6 years while that of pathological short stature patients was 2.1 years (p<0.001). Patients with NVSS had significantly higher median height SDS (HSDS) than patients with pathological diseases. The common etiologies in severe short patients, defined by HSDS ≤-3, were syndromic short stature (16.2%) and GHD (14.1%). In the moderate short stature group (HSDS between -2 and -3), constitutional delay of growth and puberty (CDGP) was the most common etiology (34.1%). CONCLUSIONS: NVSS was the most common etiology of short stature, followed by syndromic short stature and GHD. Physical examination is crucial to identify GHD from syndromic short patients.

Association between urinary phthalates and metabolic abnormalities in obese Thai children and adolescents.

BACKGROUND: Several endocrine disruptors (including phthalates) are considered to be a cause of obesity. However, the current evidence has not conclusively established an association between phthalates and metabolic abnormalities, especially in children. The objective of the study was to evaluate the association between urinary phthalate metabolites and metabolic abnormalities in obese Thai children and adolescents. METHODS: This cross-sectional case-control study was conducted in participants aged 7-18 years and divided into two groups: normal weight and overweight/obesity. Spot urine concentrations of two phthalate metabolites (monomethyl phthalate [MMP] and mono-n-buthyl phthalate [MBP]) were measured by high performance liquid chromatography (HPLC). Anthropometric data, including weight, height, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHTR), were measured and calculated. Fasting plasma glucose, insulin, HbA1c, lipid profiles and hepatic transaminase were analyzed, and insulin resistance indices were calculated. RESULTS: One hundred and fifty-five participants were included. The median MMP level in the normal weight and the overweight/obesity groups were 0 (0, 459.83) and 0 (0, 1623.50) µg/g Cr, respectively (p=0.933). The median MBP level in the normal weight and the overweight/obesity groups were 233.6 (118.1, 633.62) and 206.94 (7.4, 427.7) µg/g Cr, respectively (p=0.083). After adjusting for age, gender and puberty, there was no correlation between MBP and all anthropometric data and metabolic profiles. Participants with hypertriglyceridemia had lower MBP levels than those with normal TG level. MMP levels were not significantly different between the participants with normal and abnormal weight of all metabolic parameters. CONCLUSIONS: Participants with hypertriglyceridemia had lower MBP levels than those with normotriglyceridemia. However, it cannot show the correlation between phthalate and metabolic parameters.

DKA with Severe Hypertriglyceridemia and Cerebral Edema in an Adolescent Boy: A Case Study and Review of the Literature.

A 13-year-old adolescent boy with type 1 diabetes mellitus (1b) presented with diabetic ketoacidosis (DKA) and cerebral edema. Grossly lipemic serum and lipemia retinals due to extremely high triglyceride (TG) level were observed without evidence of xanthoma or xanthelasma. Cerebral edema was treated by appropriate ventilation and mannitol administration. Normal saline was carefully given and regular insulin was titrated according to blood sugar levels. Triglyceride levels were reduced from 9,800 mg/dL to normal range within 9 days after conventional treatment was commenced without antilipid medication. Based on our review of the literature, this is the first reported case of confirmed pediatric DKA with severe hypertriglyceridemia and cerebral edema. In patients with DKA and hypertriglyceridemia, clinicians should be mindful of the possibility of associated acute pancreatitis and cerebral edema.