MedGen

Hypogonadotropic hypogonadism is characterized by reduced function of the gonads (testes in males or ovaries in females) and results from the absence of the gonadal stimulating pituitary hormones [from HPO]

Inability to conceive for at least one year after trying and having unprotected sex. Causes of female infertility include endometriosis, fallopian tubes obstruction, and polycystic ovary syndrome. Causes of male infertility include abnormal sperm production or function, blockage of the epididymis, blockage of the ejaculatory ducts, hypospadias, exposure to pesticides, and health related issues. [from NCI]

A decreased functionality of the gonad. [from HPO]

An inflammatory process in the pituitary gland. [from NCI]

Ventricular fibrillation (VF) is said to cause more than 300,000 sudden deaths each year in the US alone. In approximately 5 to 12% of cases, there are no demonstrable cardiac or noncardiac causes to account for the episode, which is therefore classified as idiopathic ventricular fibrillation (IVF). Patients with a distinct form of VF called Brugada syndrome (see 601144) present with a characteristic electrocardiographic pattern, with right bundle branch block (RBBB) and elevation of ST segment in leads V1 to V3 and may account for 40 to 60% of all IVF cases (review by Chen et al., 1998). Mutations in the SCN5A gene were identified in patients with Brugada syndrome-1 (601144). Genetic Heterogeneity of Paroxysmal Familial Ventricular Fibrillation Another familial form of VF (VF2; 612956) is caused by mutation in the DPP6 gene (126141) on chromosome 7q26. [from OMIM]

A rare, genetic, cardiac rhythm disease characterized by ventricular fibrillation in the absence of any structural or functional heart disease, or known repolarization abnormalities. The presence of J waves is associated with a higher risk of nocturnal ventricular fibrillation events and a higher risk of recurrence. [from ORDO]

Klinefelter syndrome, also called 47,XXY, is a chromosomal condition that affects development in people who are assigned male at birth. The signs and symptoms of Klinefelter syndrome vary. In some cases, the features are so mild that the condition is not diagnosed until puberty or adulthood. Researchers believe that up to 65 percent of people with Klinefelter syndrome are never diagnosed.

Individuals with Klinefelter syndrome typically have small testes that produce a reduced amount of testosterone (primary testicular insufficiency). Testosterone is the hormone that directs male sexual development before birth and during puberty. A small percentage of affected individuals are born with undescended testes (cryptorchidism). Without treatment, the shortage of testosterone can lead to delayed or incomplete puberty, breast enlargement (gynecomastia), decreased muscle mass, decreased bone density, a reduced amount of facial and body hair, and fatigue. Klinefelter syndrome can make it difficult for people with this condition to have biological children (a condition called infertility), but up to half of people with Klinefelter syndrome may be able to have children using assisted reproductive technologies.. 

The other physical changes associated with Klinefelter syndrome are usually subtle. Most commonly, affected individuals are taller than average and 2 to 3 inches taller than would be expected for their family. Other features can include curved pinky fingers (fifth finger clinodactyly), flat feet (pes planus), and, less commonly, abnormal fusion of certain bones in the forearm (radioulnar synostosis).

Children with Klinefelter syndrome may have low muscle tone (hypotonia), difficulty coordinating movements, and mild delays of certain developmental skills, such as rolling over or walking. Affected children have an increased risk of mild delays in speech and language development. People with Klinefelter syndrome tend to have better receptive language skills (the ability to understand speech) than expressive language skills (vocabulary and the production of speech) and may have difficulty communicating and expressing themselves. Affected individuals have an increased risk for learning disabilities, most commonly problems with reading (dyslexia) and written expression. People with Klinefelter syndrome very rarely have intellectual disabilities. 

Individuals with Klinefelter syndrome may have have anxiety, depression,  impaired social skills, or behavioral differences, such as emotional immaturity during childhood or difficulty with frustration. Affected individuals also have an increased risk for attention-deficit/hyperactivity disorder (ADHD), though they tend to have problems with attention and distractability rather than hyperactivity. People with Klinefelter syndrome are more likely than those without Klinefelter syndrome to have autism spectrum disorder, which is a developmental disorder that affects communication and social interaction.

People with Klinefelter syndrome have an increased risk of developing metabolic syndrome, which is a group of conditions that include high blood glucose levels during prolonged periods without food (fasting), high blood pressure (hypertension), increased belly fat, and high levels of fats (lipids) such as cholesterol and triglycerides in the blood. Compared with unaffected people, adults with Klinefelter syndrome also have an increased risk of developing involuntary trembling (tremors) in their arms or hands, breast cancer (if gynecomastia develops), thinning and weakening of the bones (osteoporosis), and autoimmune disorders such as systemic lupus erythematosus and rheumatoid arthritis. Autoimmune disorders are a large group of conditions that occur when the immune system attacks the body's own tissues and organs. [from MedlinePlus Genetics]

Infertility in a woman. [from NCI]

Decreased functionality of the female gonads, i.e., of the ovary. [from HPO]

Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is characterized by inappropriately low serum concentrations of the gonadotropins LH (luteinizing hormone) and FSH (follicle-stimulating hormone) in the presence of low circulating concentrations of sex steroids. IGD is associated with a normal sense of smell (normosmic IGD) in approximately 40% of affected individuals and an impaired sense of smell (Kallmann syndrome) in approximately 60%. IGD can first become apparent in infancy, adolescence, or adulthood. Infant boys with congenital IGD often have micropenis and cryptorchidism. Adolescents and adults with IGD have clinical evidence of hypogonadism and incomplete sexual maturation on physical examination. Adult males with IGD tend to have prepubertal testicular volume (i.e., <4 mL), absence of secondary sexual features (e.g., facial and axillary hair growth, deepening of the voice), decreased muscle mass, diminished libido, erectile dysfunction, and infertility. Adult females have little or no breast development and primary amenorrhea. Although skeletal maturation is delayed, the rate of linear growth is usually normal except for the absence of a distinct pubertal growth spurt. [from GeneReviews]

Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is characterized by inappropriately low serum concentrations of the gonadotropins LH (luteinizing hormone) and FSH (follicle-stimulating hormone) in the presence of low circulating concentrations of sex steroids. IGD is associated with a normal sense of smell (normosmic IGD) in approximately 40% of affected individuals and an impaired sense of smell (Kallmann syndrome) in approximately 60%. IGD can first become apparent in infancy, adolescence, or adulthood. Infant boys with congenital IGD often have micropenis and cryptorchidism. Adolescents and adults with IGD have clinical evidence of hypogonadism and incomplete sexual maturation on physical examination. Adult males with IGD tend to have prepubertal testicular volume (i.e., <4 mL), absence of secondary sexual features (e.g., facial and axillary hair growth, deepening of the voice), decreased muscle mass, diminished libido, erectile dysfunction, and infertility. Adult females have little or no breast development and primary amenorrhea. Although skeletal maturation is delayed, the rate of linear growth is usually normal except for the absence of a distinct pubertal growth spurt. [from GeneReviews]

The state of being a eunuch, a male without testes or whose testes failed to develop. It is characterized by the lack of mature male germ cells and testicular hormones. [from MONDO]