The Child with Dysmorphic Features
John C. Carey
I. Description of the problem.
A. Epidemiology.
Approximately 3%-4% of all infants have a medically significant congenital malformation (see Table 35-1 for definition of terms).
About 30% of all children have a single minor anomaly or mild malformation.
An additional 10% show two or more of these physical findings.
II. Making the diagnosis.
A. The diagnosis of a multiple congenital anomaly syndrome is significant for the child, the family, and the healthcare professionals, for a number of reasons.
1. Recurrence chances in genetic counseling. The recognition of an established disorder of known etiology provides information on the cause and heritable aspects of the condition, as well as potential prenatal options for future pregnancies.
2. Relative prediction of prognosis. Each disorder has its own particular natural history, risks for problems, and outcomes.
3. Appropriate laboratory testing and screening. Precise diagnosis informs medical management and eliminates the need for unnecessary tests; appropriate screening can be planned according to the particular natural history of the syndrome.
4. Treatment and management issues. Knowledge of the natural history of a condition allows for the establishment of guidelines for routine care, including suggestions for educational interventions.
5. Coping with the disorder. In many families, the knowledge of a condition helps in dealing with the uncertainty of the situation.
B. Data collection. The importance of a thorough history in the evaluation of a child with a potential syndrome cannot be overemphasized. Information on the gestational and birth history should include history of fetal movement, drugs and medications taken during pregnancy including alcohol consumption, intrauterine positioning, status of amniotic fluid, and maternal medical history. Documentation of a complete family history with a three-generation pedigree (including inquiry regarding consanguinity) is essential. Key clinical questions include the following:
1. Does the child in question have an organized pattern of malformation (i.e., a syndrome or sequence), or does the child exhibit a constellation of features that are consistent with the family and/or ethnic background (variant familial developmental pattern)?
a. If the child has a pattern, do the findings consist of multiple primary malformations or dysplasias (a syndrome), or do the findings represent secondary manifestations (deformations or disruptions) comprising a sequence?
b. If the child has a pattern, does the pattern represent a known syndrome (or sequence), or is it a previously unidentified, provisionally unique pattern?
2. What is the date of the onset of the physical abnormalities? Are they prenatal or postnatal? Some physical signs that are clues for syndromes are of postnatal onset and often provide signs for a metabolic disorder (e.g., the facial changes and joint contractures of the mucopolysaccharidosis and other storage disorders).
C. Physical examination of the craniofacies. The ability to recognize and interpret minor anomalies and mild malformations is the most important skill required in approaching the child with a potential syndrome. The practitioner needs to be observant and skilled in describing physical variations and deciding what, in fact, is a useful clue and what is not (Fig. 35-1). The evaluation of the face and hands is particularly important since most malformation syndromes have phenotypic variations in these regions. The common frustration of clinicians in approaching the potentially dysmorphic child probably helped lead to that pejorative, stigmatizing term, the “FLK” (funny-looking kid), which should be eliminated from the clinical vocabulary.
Table 35-1. Definitions of commonly used terms
Term
Definition
Malformation
A primary morphologic defect of an organ or body part resulting from an intrinsically abnormal developmental process (e.g., cleft lip)
Deformation
An alteration of the form, shape, or position of a previously normally formed body part caused by mechanized forces (e.g., club foot due to oligohydramnios)
Sequence
Pattern of multiple anomalies derived from a single known anomaly; a primary defect with its secondary changes (e.g., Pierre Robin sequence)
Syndrome
A recurring pattern of multiple defects due to a single etiology (e.g., Williams syndrome)
Dysmorphic
abnormally formed; more conventionally, used to refer to the presence of multiple minor anomalies or mild malformations, as in dysmorphic facial features
Source: Adapted from the recommendations of the International Working Group. Spranger J, Benirschke K, Hall JG, et al. Errors of morphogenesis: concepts and terms. J Pediatr 100:160-165, 1982.
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