The Laboratory Features of Congenital Hypothyroidism and Approach to Therapy

Mutation screening of eight genes and comparison of the clinical data in a Chinese cohort with congenital hypothyroidism

BACKGROUND

Congenital hypothyroidism (CH) is a common neonatal endocrine disorder, characterized by irreversible intellectual disability and short stature if left untreated. It can be divided into thyroid dysgenesis (TD), including athyreosis, ectopy and hypoplasia, and dyshormonogenesis (DH), also referring to gland in situ (GIS), in which patients have eutopic thyroids with normal size or goiter. This study aims to analyze the clinical and genetic data of 375 Chinese CH patients without DUOX2 and thyroid transcription factor (TTF) variants, and to explore the mutation frequencies of the eight genes and the inheritance pattern of CH.

METHODS

Targeted next generation sequencing (NGS) and statistical analysis were performed for mutation screening on eight CH-related genes and the comparison of clinical data in a cohort of 606 Chinese CH patients from Henan Province.

RESULTS

A total of 104 variants were detected in genes required for thyroid formation (TSHR, GLIS3, BOREALIN, NTN1, JAG1 and TUBB1) and thyroid hormone synthesis (TG and TPO) in 83 subjects. Monogenic variants were the most prevalent with a percentage of 75.00% (78/104) followed by oligogenic variants (25.00%, 26/104). No differences were found in various clinical data between patients with and without variants. However, it should be noted that only initial L-T4 dose was statistically different between patients with monogenic variants and oligogenic variants.

CONCLUSIONS

Our results suggested that apart from Mendelian monogenic inheritance, oligogenic inheritance of CH could not be excluded and also involves other factors, such as penetrance, epigenetic mechanisms and environmental factors.

Relationship between thyroid hormones and central nervous system metabolism in physiological and pathological conditions

Thyroid hormones (THs) play an important role in the regulation of energy metabolism. They also take part in processes associated with the central nervous system (CNS), including survival and differentiation of neurons and energy expenditure. It has been reported that a correlation exists between the functioning of the thyroid gland and the symptoms of CNS such as cognitive impairment, depression, and dementia. Literature data also indicate the influence of THs on the pathogenesis of CNS diseases, such as Alzheimer's disease, epilepsy, depression, and Parkinson's disease. This review describes the relationship between THs and metabolism in the CNS, the effect of THs on the pathological conditions of the CNS, and novel options for treating these conditions with TH derivatives.

Overview of Congenital Hypopituitarism for the Neonatologist

Congenital hypopituitarism is the deficiency in 1 or more hormones produced by the anterior pituitary or released by the posterior pituitary and has an estimated incidence of 1 in 4,000 to 10,000. Due to the critical role the pituitary plays in growth, metabolic, and reproductive processes, early diagnosis is essential to prevent devastating and often preventable outcomes. However, in neonates with congenital hypopituitarism, symptoms are often nonspecific and tend to overlap with other disease processes, making diagnosis extremely challenging in the neonatal period. This review highlights the embryology and organogenesis of the pituitary gland, genetic causes of hypopituitarism, clinical presentations in the neonatal period, and methods to diagnose and treat select deficiencies with a focus on anterior pituitary hormones.

Genetics of Thyroid Disorders

Thyroid diseases in children and adolescents include acquired or congenital conditions, including genetic disorders either isolated or part of a syndrome. Briefly, we will review the physiology and pathophysiology of the thyroid gland and its disorders. The aim of this chapter is to describe genetic abnormalities of the thyroid gland.

Improving timeliness of newborn screens in the neonatal intensive care unit: a quality improvement initiative

BACKGROUND

Despite the established utility of newborn screening tests (NBS), achieving timely specimen transit is a challenge for neonatal intensive care units (NICU).

METHODS

This project was conducted between September 2017 and July 2020 using the Plan-Do-Study-Act (PDSA) tool. Our primary aim was to increase the percent of NBS samples reaching the state laboratory within 1 day of collection by 20% by April 2020. Process, outcome, and balancing measures were monitored.

RESULTS

Five hundred and eighty-five NBS were collected. There was special cause variation with improvement in the percent of samples received within 1 day of collection from 28 to 77%. Special cause variation was also observed in the process measures without an increase in the percent of unacceptable samples.

CONCLUSIONS

Standardizing the NBS collection processes by adopting a sample collection window and same day courier pickup ensures timely specimen transit without adversely affecting the quality of samples collected.

Screening of Congenital Hypothyroidism in North-East Romania. Benefits and Messages for Further Improvement

Background

If not diagnosed at birth, congenital hypothyroidism (CH) can cause deleterious, irreversible neurodevelopmental sequels. The importance of thyroid newborn screening (NBS) is therefore well established.

Objective

To evaluate the efficacy of NBS for CH in North-East Romania.

Methods

Retrospective, descriptive study involving 271662 newborns screened between 2010 and 2019 for CH and phenylketonuria in maternities from six Romanian North-Eastern counties by measuring neonatal TSH (neoTSH) in the whole blood extracted from the heel between days 3 and 5 after birth. Values found higher than a cut-off level of 10 mIU/L were followed by serum evaluation of TSH and fT4 for the confirmation of CH. Thyroid ultrasound was further performed at children found with CH.

Results

NeoTSH was found elevated in 417 newborns, but CH was subsequently confirmed in only 57 cases (1/4766 newborns). Mean age at the time when diagnosis was communicated was of 37.2 ± 15 days (between 9 and 157 days). Mean age when therapy was started was of 44.2 ± 17.9 days (between 13 and 160 days) with a mean delay of one week from diagnosis (between 0 and 62 days). Thyroid ultrasound revealed athyreosis in only 3 cases, atrophic thyroid gland in other 10 cases, whereas the thyroid was described as present in the remnant 44 cases. The number of first year follow-up visits greatly varied from 0 to 5, with an average of 2.

Conclusions

NBS allowed rapid diagnosis of CH in North East Romania. The communication of diagnosis to families and therapy onset were however often delayed. Diagnosis and therapy onset before the age of two weeks, as well as a tighter follow-up should be assured by the healthcare system. Etiological diagnosis should be more accurate, for a better prognosis of disease severity, as well as the possibility of genetic advice in selected cases.