A pedigree comprising at least three generations should be constructed, searching for similar or dissimilar abnormalities in firstand second-degree relatives. A history of pregnancy or neonatal losses should be documented. For a more detailed discussion of pedigrees, see Chapter 47.
When examining children with dysmorphic features, the following approach should be used.
The height (length), weight, and head circumference should bemeasured carefully and plotted on appropriate growth curves.Small size or growth restriction may be secondary to a chromosomal abnormality, skeletal dysplasia, or exposure to toxic orteratogenic agents. Larger than expected size suggests an overgrowth syndrome (Sotos or Beckwith-Wiedemann syndrome)or, in the newborn period, might suggest a diabetic mother.
The clinician should note if the child is proportionate. Limbsthat are too short for the head and trunk imply the presence ofa short-limbed bone dysplasia, such as achondroplasia. A trunkand head that are too short for the extremities suggest a disorderaffecting the vertebrae, such as spondyloepiphyseal dysplasia.
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Abnormal Head Size, Shape, and Fontanels
Careful examination of the head and face is crucial for the diagnosis of many congenital malformation syndromes. Head shape should be carefully assessed; if the head is not normal in size and shape (normocephalic), it may be long and thin (dolichocephalic), short and wide (brachycephalic), or asymmetric or lopsided (plagiocephalic).
Any asymmetry of facial features should be noted. Asymmetry may be due to a deformation related to intrauterine positionor a malformation of one side of the face. The face should be divided into four regions, which are evaluated separately. Theforehead may show overt prominence (achondroplasia) or deficiency (often described as a sloping appearance, which occurs inchildren with primary microcephaly). The midface, extendingfrom the eyebrows to the upper lip and from the outer canthi ofthe eyes to the commissures of the mouth, is especially important. Careful assessment of the distance between the eyes (innercanthal distance) and the pupils (interpupillary distance) mayconfirm the impression of hypotelorism (eyes that are too closetogether), which suggests a defect in midline brain formation, or hypertelorism (eyes that are too far apart). The length of thepalpebral fissure should be noted and may help define whetherthe opening for the eye is short, as is found with fetal alcoholsyndrome, or excessively long, as in Kabuki makeup syndrome(short stature, mental retardation, long palpebral fissures witheversion of lateral portion of lower lid).
Other features of the eyes should be noted. The obliquity(slant) of the palpebral fissures may be upward (as seen withDown syndrome) or downward (as in Treacher Collins syndrome). The presence of epicanthal folds (Down syndromeand fetal alcohol syndrome) is also important. Features of the nose—especially the nasal bridge, which can be flattened in Down syndrome, fetal alcohol syndrome, and many other syndromes, or prominent as in velocardiofacial syndrome—shouldbe noted.
The malar region of the face is examined next. It extends from the ear to the midface. The ears should be checked for size (measured and checked against appropriate growth charts), shape, position (low-set ears are below a line drawn from the outer canthus to the occiput), and orientation (posterior rotation is where the ear appears turned toward the rear of the head). Ears may be low set because they are small (or microtic) or because of a malformation of the mandibular region.