pediatrics
Microcephaly
Diagnosis
Prenatally, ultrasound Postnatally, physical examination, including measurement of head circumference and cranial imaging Genetic testing Prenatally, the diagnosis of microcephaly sometimes is made with ultrasonography done in the late second or early third trimester. Postnatally, evaluation should include detailed prenatal history to identify risk factors, developmental and neurologic assessment, and brain MRI or CT. Primary autosomal recessive microcephaly may involve a defect in one or more of at least four genes. A clinical geneticist should evaluate affected patients even in cases of apparent isolated congenital anomaly. Among the genetic syndromes to be considered are Seckel syndrome, Smith-Lemli-Opitz syndrome, syndromes due to defective DNA repair (eg, Fanconi and Cockayne syndromes), and Angelman syndrome. For parents of an affected child, risk of the disorder appearing in subsequent offspring may be as high as 25%, depending on which syndrome is present, and thus clinical genetic assessment is necessary. A gene panel test specific for microcephaly is available through several diagnostic laboratories. Diagnosis , or broader gene panel tests also should be considered in the evaluation of patients with microcephaly. If the results of these tests are nondiagnostic, whole exome sequencing analysis is recommended. 