Intense feelings of nervousness, tenseness, or panic, often in reaction to interpersonal stresses; worry about the negative effects of past unpleasant experiences and future negative possibilities; feeling fearful, apprehensive, or threatened by uncertainty; fears of falling apart or losing control.

Astigmatism (from the Greek 'a' meaning absence and 'stigma' meaning point) is a condition in which the parallel rays of light entering the eye through the refractive media are not focused on a single point. Both corneal and noncorneal factors contribute to refractive astigmatism. Corneal astigmatism is mainly the result of an aspheric anterior surface of the cornea, which can be measured readily by means of a keratometer; in a small fraction of cases (approximately 1 in 10) the effect is neutralized by the back surface. The curvature of the back surface of the cornea is not considered in most studies, because it is more difficult to measure; moreover, in the case of severe corneal astigmatism, there is evidence that both surfaces have the same configuration. Noncorneal factors are errors in the curvature of the 2 surfaces of the crystalline lens, irregularity in the refractive index of the lens, and an eccentric lens position. Since the cornea is the dominant component of the eye's refracting system, a highly astigmatic cornea is likely to result in a similarly astigmatic ocular refraction (summary by Clementi et al., 1998).

A position of the fetus at delivery in which the fetus enters the birth canal with the buttocks or feet first.

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).

A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.

An abnormality of refraction characterized by the ability to see objects in the distance clearly, while objects nearby appear blurry.

Although hypertelorism means an excessive distance between any paired organs (e.g., the nipples), the use of the word has come to be confined to ocular hypertelorism. Hypertelorism occurs as an isolated feature and is also a feature of many syndromes, e.g., Opitz G syndrome (see 300000), Greig cephalopolysyndactyly (175700), and Noonan syndrome (163950) (summary by Cohen et al., 1995).

Deficiency of thyroid hormone.

Klippel-Feil syndrome (KFS) is a congenital anomaly characterized by a defect in the formation or segmentation of the cervical vertebrae, resulting in a fused appearance. The clinical triad consists of short neck, low posterior hairline, and limited neck movement, although less than 50% of patients demonstrate all 3 clinical features (Tracy et al., 2004). Genetic Heterogeneity of Klippel-Feil Syndrome Additional forms of KFS include autosomal recessive KFS2 (214300), caused by mutation in the MEOX1 gene (600147) on chromosome 17q21, autosomal dominant KFS3 (613702), caused by mutation in the GDF3 gene (606522) on chromosome 12p13, and autosomal recessive KFS4 (616549), caused by mutation in the MYO18B gene (607295) on chromosome 22q12. See also MURCS association (601076), in which Klippel-Feil anomaly is associated with urogenital anomalies.

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

An appetite for and the persistent ingestion of non-food substances such as clay. In order to diagnose pica, this behavior must have persisted over a period of at least one month.

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

An abnormality of sleep including such phenomena as 1) insomnia/hypersomnia, 2) non-restorative sleep, 3) sleep schedule disorder, 4) excessive daytime somnolence, 5) sleep apnea, and 6) restlessness.

A stereotypy is a repetitive, simple movement that can be voluntarily suppressed. Stereotypies are typically simple back-and-forth movements such as waving of flapping the hands or arms, and they do not involve complex sequences or movement fragments. Movement is often but not always rhythmic and may involve fingers, wrists, or more proximal portions of the upper extremity. The lower extremity is not typically involved. Stereotypies are more commonly bilateral than unilateral.

A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error.

A deformity of the chest caused by overgrowth of the ribs and characterized by protrusion of the sternum.

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.

Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.

Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age.

Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear.

A facial appearance characterized by a permanently or nearly permanently opened mouth.

Nasal ridge curving anteriorly to an imaginary line that connects the nasal root and tip. The nose appears often also prominent, and the columella low.

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).

Abnormal protrusion of the scapula away from the surface of the back.

Nystagmus consisting of horizontal to-and-fro eye movements.

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.

An eye that is more deeply recessed into the plane of the face than is typical.

Hyperactivity is a state of constantly being unusually or abnormally active, including in situations in which it is not appropriate.

Distance between subnasale and pronasale more than two standard deviations above the mean, or alternatively, an apparently increased anterior protrusion of the nasal tip.

Meeting of the medial eyebrows in the midline.

Absence of both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum.

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

Increased body weight with a body mass index of 25-29.9 kg per square meter.

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

Increased blood pressure during a pregnancy.

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.

Flat skin surface, with no ridge formation in the central region of the upper lip between the nasal base and upper vermilion border.

An asymmetriy, i.e., difference in size, shape or position between the left and right ear.

An abnormal accentuation of the inward curvature of the spine in the lumbar region.

A larger than usual distance between the left and right nipple.

The presence of one or more obsessive-compulsive personality traits. Obsessions refer to persistent intrusive thoughts, and compulsions to intrusive behaviors, which the affected person experiences as involuntary, senseless, or repugnant.

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

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).

Distance between the hairline (trichion) and the glabella (the most prominent point on the frontal bone above the root of the nose), in the midline, more than two SD below the mean. Alternatively, an apparently decreased distance between the hairline and the glabella.

Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.

Anterior positioning of the nasal root in comparison to the usual positioning for age.

Complete lack of development of speech and language abilities.

Distance between nasal base and midline upper lip vermilion border more than 2 SD below the mean. Alternatively, an apparently decreased distance between nasal base and midline upper lip vermilion border.

A morphological abnormality of the mouth in which the angle of the mouth is downturned. The oral commissures are positioned inferior to the midline labial fissure.

Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.

A proneness to anger, i.e., a condition of being easily bothered or annoyed.

Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

Delayed myelination in the central nervous system.

Head circumference below 2 standard deviations below the mean for age and gender.

A state of abnormally strong desire for sleep during the daytime.