The retrograde (backwards) flow of blood through the pulmonary valve into the right ventricle during diastole.

A conduction block of the right branch of the bundle of His. This manifests as a prolongation of the QRS complex (greater than 0.12 s) with delayed activation of the right ventricle and terminal delay on the EKG.

The dividing wall between left and right sides of the heart, thickens and bulges into the left ventricle.

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

A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).

A deficiency or slowing down of growth pre- and postnatally.

A reduced desire to eat.

A brighter than expected signal on magnetic resonance imaging emanating from the cerebral white matter.

Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis.

A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger).

A break or crush injury of the thigh bone (femur).

Developmental hypoplasia of the mandible.

Reduced strength of muscles.

Reduced length of the clavicles.

A reduced amount of fat tissue in the lowest layer of the integument. This feature can be appreciated by a reduced skinfold thickness.

Reduced depth of the orbits associated with prominent-appearing ocular globes.

A reduction of bone mineral density, that is, of the amount of matter per cubic centimeter of bones.

The presence of extra bones within a cranial suture. Wormian bones are irregular isolated bones which appear in addition to the usual centers of ossification of the cranium.

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

Increased resistance towards insulin, that is, diminished effectiveness of insulin in reducing blood glucose levels.

Tooth agenesis in some form is a common human anomaly that affects approximately 20% of the population. Although tooth agenesis is associated with numerous syndromes, several case reports describe nonsyndromic forms that are either sporadic or familial in nature, as reviewed by Gorlin et al. (1990). The incidence of familial tooth agenesis varies with each class of teeth. Most commonly affected are third molars (wisdom teeth), followed by either upper lateral incisors or lower second premolars; agenesis involving first and second molars is very rare. Also see 114600 and 302400. Selective tooth agenesis without associated systemic disorders has sometimes been divided into 2 types: oligodontia, defined as agenesis of 6 or more permanent teeth, and hypodontia, defined as agenesis of less than 6 teeth. The number in both cases does not include absence of third molars (wisdom teeth). Faulty use of the terms, however, have confounded their use. The term 'partial anodontia' is obsolete (Salinas, 1978). Genetic Heterogeneity of Selective Tooth Agenesis Other forms of selective tooth agenesis include STHAG2 (602639), mapped to chromosome 16q12; STHAG3 (604625), caused by mutation in the PAX9 gene (167416) on chromosome 14q12; STHAG4 (150400), caused by mutation in the WNT10A gene (606268) on chromosome 2q35; STHAG5 (610926), mapped to chromosome 10q11; STHAG7 (616724), caused by mutation in the LRP6 gene (603507) on chromosome 12p13; STHAG8 (617073), caused by mutation in the WNT10B gene (601906) on chromosome 12q13; STHAG9 (617275), caused by mutation in the GREM2 gene (608832) on chromosome 1q43; STHAG10 (620173), caused by mutation in the TSPEAR gene (612920) on chromosome 21q22; and STHAGX1 (313500), caused by mutation in the EDA gene (300451) on chromosome Xq13. A type of selective tooth agenesis that was formerly designated STHAG6 has been incorporated into the dental anomalies and short stature syndrome (DASS; 601216). Of 34 unrelated patients with nonsyndromic tooth agenesis, van den Boogaard et al. (2012) found that 56% (19 patients) had mutations in the WNT10A gene (STHAG4), whereas only 3% and 9% had mutations in the MSX1 (STHAG1) and PAX9 (STHAG3) genes, respectively. The authors concluded that WNT10A is a major gene in the etiology of isolated hypodontia. Genotype-Phenotype Correlations Yu et al. (2016) observed that the most frequently missing permanent teeth in WNT10B-associated oligodontia were the lateral incisors (83.3%), whereas premolars were missing only 51.4% of the time, which they noted was a pattern 'clearly different' from the oligodontia patterns resulting from WNT10A mutations. They also stated that the selective pattern in WNT10B mutants was different from that associated with mutations in other genes, such as MSX1, in which second premolars are missing, and PAX9, in which there is agenesis of molars.

Distance between the commissures of the mouth more than 2 SD below the mean. Alternatively, an apparently decreased width of the oral aperture (subjective).

A tooth which does not erupt within the teeth eruption timeline and after the loss of eruption potential.

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.

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

Facial contour, as viewed from the front, triangular in shape, with breadth at the temples and tapering to a narrow chin.

Delayed tooth eruption affecting the primary dentition.

Posterior positions and/or vertical shortening of the infraorbital and perialar regions, or increased concavity of the face and/or reduced nasolabial angle.

A condition in which superficial veins (i.e., veins just under the skin) are more conspicuous or noticable than normal.

Premature rupture of membranes (PROM) is a condition which occurs in pregnancy when the amniotic sac ruptures more than an hour before the onset of labor.

An eye that is protruding anterior to the plane of the face to a greater extent than is typical.