Klinefelter syndrome

the most common primary developmental abnormality causing (primary hypergonadotropic) hypogonadism (testicular damage)

affects 1 of every 400-500 males

80% have a 47,XXY karyotype (due to nondisjunction of a sex chromosome)

Gynecomastia is found with elevated levels of LH and FSH,

sterility and lack of libido

Males affected by Klinefelter syndrome have a 20x increased risk of breast cancer

Kallmann syndrome (hypogonadic hypogonadism) secondary

decreased sense of smell; absent pubic, axillary hair, absent breasts, amenorrhea

Pathophisiology:

a failure of GnRH-secreting neurons to migrate from their origin in the olfactory placode (situated outside the CNS) to their normal anatomic location in the hypothalamus.

Most often, the cause is a mutation in the KAL-1 gene or the fibroblast growth factor receptor-1 gene, which code for proteins required in this migration.

Sirenomelia, alternatively known as Mermaid Syndrome

Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula and/or Esophageal atresia, Renal & Radial anomalies and Limb defects.