46,XY Differences of Sexual Development

ABSTRACT   The 46,XY differences of sex development (46,XY DSD) can result either from decreased synthesis of testosterone and/or DHT or from impairment of androgen action. 46,XY DSD are characterized by micropenis, atypical or female external genitalia, caused by incomplete intrauterine masculinization with or without the presence of Müllerian structures. Male gonads are identified in […]

Primary Disorders of Phosphate Metabolism

ABSTRACT   Phosphorus is critical to many functions in human biology. Deprivation of phosphorus may manifest as disorders of the musculoskeletal system, reflecting its important role in energy metabolism and skeletal mineralization. Phosphorus excess can promote heterotopic mineralization and is associated with mortality, particularly in the setting of chronic kidney disease. Inorganic phosphorus, primarily occurring […]

Disorders of Growth Hormone in Childhood

ABSTRACT   Growth is a fundamental process of childhood and growth disorders remain one of the commonest reasons for referral to a pediatric endocrinologist. Growth can be divided into four phases – fetal, infancy, childhood and the pubertal phase with different hormonal components influencing growth at each stage. The GH-IGF1 axis plays a major role […]

Monogenic Disorders Causing Hypobetalipoproteinemia – copy

ABSTRACT   Monogenic mutations leading to hypobetalipoproteinemia are rare. The monogenic causes of hypobetalipoproteinemia include familial hypobetalipoproteinemia, abetalipoproteinemia, chylomicron retention disease, loss of function mutations in PCSK9, and loss of function mutations in angiopoietin-like protein 3 (ANGPTL3) (Familiar Combined Hypolipidemia). This chapter describes the etiology, pathogenesis, clinical and laboratory findings, and the treatment of these […]

Benign Prostate Disorders

ABSTRACT   Benign prostatic hyperplasia (BPH) is among the commonest urological abnormalities affecting the aging male. The cause of the increase in prostatic volume is multifactorial, but current research has implicated hormonal aberrations. Clinical assessment of the patient is integral to determining the optimal treatment strategy. Exclusion of prostatic cancer and complications of BPH are […]

Calcium and Phosphate Metabolism and Related Disorders During Pregnancy and Lactation

ABSTRACT   Pregnancy and lactation require women to provide calcium to the fetus and neonate in amounts that may exceed their normal daily intake. Specific adaptations are invoked within each time period to meet the fetal, neonatal, and maternal calcium requirements. During pregnancy, intestinal calcium absorption more than doubles, and this appears to be the […]

Androgen Physiology: Receptor and Metabolic Disorders

ABSTRACT   Androgens are an important class of C19 steroid hormones that control normal male development and reproductive function. The main circulating androgen is testosterone, which is produced in the Leydig cells of the testis and can also act as a pro-hormone after being metabolized to dihydrotestosterone (DHT) or estradiol (E2). The biological actions of […]

Adrenal Disorders in the Tropics

ABSTRACT   The adrenal gland in conjunction with the pituitary gland is one of the major components of the endocrine system and regulates blood volume, blood pressure, serum electrolytes, and stress responses. Dysfunction of the adrenal glands may be related to diseases of the adrenal glands or pituitary gland. Adrenal disorders may present either due […]

Growth and Growth Disorders

ABSTRACT   The process of growth is complex and is influenced by various factors that act centrally and peripherally. The genetic control of human growth is becoming increasingly clear. Many genes have been identified that contribute to the development and function of the pituitary gland including the somatotrope and the GH/IGF1 axis.  Genes encoding “downstream” […]

Monogenic Disorders Causing Hypobetalipoproteinemia

ABSTRACT   Monogenic mutations leading to hypobetalipoproteinemia are rare. The monogenic causes of hypobetalipoproteinemia include familial hypobetalipoproteinemia, abetalipoproteinemia, chylomicron retention disease, loss of function mutations in PCSK9, and loss of function mutations in angiopoietin-like protein 3 (ANGPTL3) (Familiar Combined Hypolipidemia). This chapter describes the etiology, pathogenesis, clinical and laboratory findings, and the treatment of these […]