Craniofacial and musculoskeletal abnormalities are common among children. They may involve only a single, specific site (eg, cleft lip, cleft palate, clubfoot) or be part of a syndrome of multiple congenital anomalies (eg, velocardiofacial syndrome, Treacher Collins syndrome). Careful clinical assessment may be necessary to distinguish an isolated abnormality from an atypical or mildly manifested syndrome.
Congenital abnormalities may be classified as
Deformities
Malformations
A deformity is an alteration in shape due to unusual pressure and/or positioning in utero (eg, some forms of club foot) or after birth (eg, positional plagiocephaly—head flattening due to prolonged lying in one position). Deformities are present in about 2% of births; some resolve spontaneously within a few days, but others persist and require treatment.
A malformation is an error in normal organ or tissue development. Causes include chromosomal abnormalities, single-gene defects, teratogenic agents, or a combination of genetic and environmental factors; a decreasing number of cases are considered idiopathic. Congenital malformations are present in about 3 to 5% of births. A clinical geneticist should assess affected patients to establish a definitive diagnosis, which is essential for formulating an optimal treatment plan, providing anticipatory guidance and genetic counseling, and identifying relatives at risk of similar abnormalities.
Arthrogryposis multiplex congenita (AMC) refers to a group of rare congenital disorders characterized by multiple joint contractures present at birth. These disorders result from congenital limitation of joint movement in utero. Many pathologic processes that cause immobilization of a fetus' limbs during or shortly after the embryonic formation of joints may result in AMC. AMC occurs when embryofetal neuromuscular function and development are impaired.
Congenital craniofacial abnormalities are caused by the abnormal growth and/or development of the head and facial soft-tissue structures and/or bones. The most common abnormalities of the face are cleft lip and cleft palate. Other abnormalities may involve the ears, eyes, and jaw. Some of the craniofacial abnormalities that affect the skull include macrocephaly, microcephaly, cranium bifidum or related ossification defects, and craniosynostosis.
Congenital hip and joint abnormalities include developmental dysplasia of the hip and knee dislocation.
Congenital limb defects are numerous. Sometimes a limb is missing or incomplete. Part or all of the hand or foot may be missing. For example, the person may have polydactyly or syndactyly. Talipes equinovarus (clubfoot) is a defect in which the foot and ankle are twisted out of shape or position. Other foot defects include metatarsus adductus, metatarsus varus, talipes calcaneovalgus, and pes planus.
In genu varum (bowlegs), the knees appear to be turned outward. In genu valgum (knock-knees), the knees appear to be turned inward. Other defects that affect the legs include femoral torsion and tibial torsion.
Muscle abnormalities may be congenital. Infants can be born missing individual muscles or groups of muscles, or muscles can be incompletely developed. Muscle abnormalities can occur alone or as part of a syndrome.
Congenital neck and back abnormalities can be caused by injuries to soft tissues or bones. Two of the most common abnormalities are
Spinal abnormalities include scoliosis, which is rarely apparent at birth, and defects of a specific vertebra, which are likely to be identified at birth. A number of different genetic syndromes include scoliosis as one of their abnormalities. As children grow, the curve can progress quickly. Moderate curves (20 to 40°) are treated conservatively (eg, physical therapy and bracing) to prevent further deformity. Severe curves (> 40°) may be ameliorated surgically (eg, spinal fusion with rod placement).
Patients with apparent congenital anomalies should be referred for clinical genetic evaluation. Chromosomal microarray, specific gene tests, or broader gene panel tests should be considered in the evaluation of patients with congenital craniofacial and musculoskeletal abnormalities. If the results of these tests are nondiagnostic, whole exome sequencing analysis is recommended.
