[Overgrowth with and without obesity: clinical and molecular principles]

Overgrowth Syndromes-Evaluation, Diagnosis, and Management

Abnormally excessive growth results from perturbation of a complex interplay of genetic, epigenetic, and hormonal factors that orchestrate human growth. Overgrowth syndromes generally present with inherent health concerns and, in some instances, an increased risk of tumor predisposition that necessitate prompt diagnosis and appropriate referral. In this review, we introduce some of the more common overgrowth syndromes, along with their molecular mechanisms, diagnostics, and medical complications for improved recognition and management of patients affected with these disorders.

A Clinical Review of Generalized Overgrowth Syndromes in the Era of Massively Parallel Sequencing

The overgrowth syndromes are important to diagnose, not just for accurate genetic counseling, but also for knowledge surrounding cancer surveillance and prognosis. There has been a recent expansion in the number of genes associated with a mendelian overgrowth phenotype, so this review updates previous classifications of overgrowth syndromes. We also describe a clinical and molecular approach to the investigation of individuals presenting with overgrowth. This review aims to assist the clinical diagnosis of generalized overgrowth syndromes by outlining the salient features of well-known overgrowth syndromes alongside the many syndromes that have been discovered and classified more recently. We provide key clinical "handles" to aid clinical diagnosis and a list of genes to aid with panel design when using next generation sequencing, which we believe is frequently needed due to the overlapping phenotypic features seen between overgrowth syndromes.

Burden of Growth Hormone Deficiency and Excess in Children

Longitudinal growth results from multifactorial and complex processes that take place in the context of different genetic traits and environmental influences. Thus, in view of the difficulties in comprehension of the physiological mechanisms involved in the achievement of normal height, our ability to make a definitive diagnosis of GH impairment still remains limited. There is a myriad of controversial aspects in relation to GH deficiency, mainly related to diagnostic controversies and advances in molecular biology. This might explain the diversity in therapeutic responses and may also serve as a rationale for new "nonclassical" treatment indications for GH. It is necessary to acquire more effective tools to reach an adequate evaluation, particularly while considering the long-term implications of a correct diagnosis, the cost, and safety of treatments. On the other hand, overgrowth constitutes a heterogeneous group of different pathophysiological situations including excessive somatic and visceral growth. There are overlaps in clinical and molecular features among overgrowth syndromes, which constitute the real burden for an accurate diagnosis. In conclusion, both GH deficiency and overgrowth are a great dilemma, still not completely solved. In this chapter, we review the most burdensome aspects related to short stature, GH deficiency, and excess in children, avoiding any details about well-known issues that have been extensively discussed in the literature.