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

An abnormal narrowing of the lumen of the esophagus.

Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time.

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.

Aplastic anemia is a serious disorder of the bone marrow that affects between 2 and 5 persons per million per year. About 75% of these cases are classified as idiopathic (Young, 2000). In about 15% of cases a drug or infection can be identified that precipitates the aplasia, although why only some individuals are susceptible is unclear. In about 5 to 10% of patients, the aplastic anemia is constitutional--i.e., is familial or presents with one or more associated somatic abnormalities (summary by Vulliamy et al., 2002).

An abnormal reduction in numbers of all blood cell types (red blood cells, white blood cells, and platelets).

A reduced number of hematopoietic cells present in the bone marrow relative to marrow fat.

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

A thickened white patch on the oral mucosa that cannot be rubbed off.

Any abnormality of the teeth.

Onychodystrophy (nail dystrophy) refers to nail changes apart from changes of the color (nail dyschromia) and involves partial or complete disruption of the various keratinous layers of the nail plate.

An abnormal reduction in telomere length. Telomeres are non-coding, repetitive sequences of DNA at the ends of the chromosomes of eukaryotic cells which become shorter as cells divide, and when telomere attrition reaches its limit, cell proliferation arrest, senescence, and apoptosis can occur.