Cryptorchidism, or failure of testicular descent, is a common human congenital abnormality with a multifactorial etiology that likely reflects the involvement of endocrine, environmental, and hereditary factors. Cryptorchidism can result in infertility and increases risk for testicular tumors. Testicular descent from abdomen to scrotum occurs in 2 distinct phases: the transabdominal phase and the inguinoscrotal phase (summary by Gorlov et al., 2002).

Abnormally small penis. At birth, the normal penis is about 3 cm (stretched length from pubic tubercle to tip of penis) with micropenis less than 2.0-2.5 cm.

An increased degree of femoral version, which is defined as the angular difference between axis of femoral neck and transcondylar axis of the knee. Thus, femoral anteversion is an inward twisting of the femur that causes the knees and feet to turn inward.

Reduced variation of beat-to-beat intervals of the heart that occurs in conjunction with the respiratory cycle.

An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.

Abnormally low body weight.

Abnormally increased size of the liver.

Constipation for longer than three months with fewer than 3 bowel movements per week, straining, lumpy or hard stools, and a sensation of anorectal obstruction or incomplete defecation.

The presence of chronic diarrhea, which is usually taken to mean diarrhea that has persisted for over 4 weeks.

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Deliberate harm to one's body resulting in tissue damage, without a conscious intent to die.

Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose.

Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp.

A degree of language development that is significantly below the norm for a child of a specified age.

Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior.

Attention-deficit/hyperactivity disorder (ADHD) is a behavioral disorder that typically begins in childhood and is characterized by a short attention span (inattention), an inability to be calm and stay still (hyperactivity), and poor impulse control (impulsivity). Some people with ADHD have problems with only inattention or with hyperactivity and impulsivity, but most have problems related to all three features.\n\nIn people with ADHD, the characteristic behaviors are frequent and severe enough to interfere with the activities of daily living such as school, work, and relationships with others. Because of an inability to stay focused on tasks, people with inattention may be easily distracted, forgetful, avoid tasks that require sustained attention, have difficulty organizing tasks, or frequently lose items.\n\nHyperactivity is usually shown by frequent movement. Individuals with this feature often fidget or tap their foot when seated, leave their seat when it is inappropriate to do so (such as in the classroom), or talk a lot and interrupt others.\n\nImpulsivity can result in hasty actions without thought for the consequences. Individuals with poor impulse control may have difficulty waiting for their turn, deferring to others, or considering their actions before acting.\n\nMore than two-thirds of all individuals with ADHD have additional conditions, including insomnia, mood or anxiety disorders, learning disorders, or substance use disorders. Affected individuals may also have autism spectrum disorder, which is characterized by impaired communication and social interaction, or Tourette syndrome, which is a disorder characterized by repetitive and involuntary movements or noises called tics.\n\nIn most affected individuals, ADHD continues throughout life, but in about one-third of individuals, signs and symptoms of ADHD go away by adulthood.

A severe delay in the achievement of motor or mental milestones in the domains of development of a child.

Reduced ability to perceive painful stimuli.

A type of Developmental delay characterized by a delay in acquiring motor skills.

A moderate delay in the achievement of motor or mental milestones in the domains of development of a child.

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

Delayed myelination in the central nervous system.

An increased amount of cerebrospinal fluid (CSF) in the subarachnoid space.

A reduction in the number of circulating thrombocytes.

An abnormal reduction below normal hemoglobin concentration in the circulation.

Exaggerated anterior convexity of the thoracic vertebral column.

Developmental hypoplasia of the mandible.

The presence of an abnormal lateral curvature of the spine.

Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.

An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture.

Asymmetric head shape, which is usually a combination of unilateral occipital flattening with ipsilateral frontal prominence, leading to rhomboid cranial shape.

Muscular hypotonia (abnormally low muscle tone) manifesting in the neonatal period.

Respiratory difficulty as newborn.

Changes in alignment of teeth in the dental arch

An abnormally increased height of the forehead.

Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).

Distance between the medial and lateral canthi is more than 2 SD below the mean for age (objective); or, apparently reduced length of the palpebral fissures.

Thinned, deficient, or excessively arched ala nasi.

Posterior positioning of the nasal root in relation to the overall facial profile for age.

Increased width of the skin of vermilion border region of upper lip.

Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).

A marked tapering of the lower face to the chin.

Width of the forehead or distance between the frontotemporales is more than two standard deviations above the mean (objective); or apparently increased distance between the two sides of the forehead.

Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.

Increased height of the central portion of the eyebrow, forming a crescent, semicircular, or inverted U shape.

Insertion of the posterior columella below the nasal base.

Mid upper eyelash length >10 mm or increased length of the eyelashes (subjective).

A form of strabismus with one or both eyes deviated outward.

Absence of tear secretion.