Autosomal Recessive Microcephaly Vera
The diagnosis of autosomal recessive microcephaly vera is based on the absence of any systemic anomaly and a history of microcephaly in the maternal or paternal families. Facial features that suggest autosomal recessive microcephaly vera are receding frontal hair, upward slanting palpebral fissures, and relatively large protruding ears. Magnetic resonance imaging shows a small well-formed brain.

Microcephaly occurs in a large number of chromosomal syndromes. Trisomy 13, 18, and 21, and 4p-, 5p-, 13q-, 18p-, and 18q-deletions are associated with microcephaly.

Down Syndrome
Down syndrome is characterized by typical facial features: epicanthal folds, prominent furrowed tongue, a flat nasal bridge, and oblique palpebral fissures with a flat occiput (Figure 275.1). Neonates with Down syndrome have a predisposition for duodenal atresia, congenital heart disease (particularly endocardial cushion defects), and leukemia. Chromosomal studies are indicated to confirm the diagnosis and to detect translocations. Parents with balance translocations are more likely to have other offspring with Down syndrome than parents who are not carriers of the translocation. More about... 111

A	B	C

Figure 275.1.— Characteristic findings in neonates with Down syndrome. [A] Upward slanting palpebral features, [B] simian crease, [C] wide space between the first and second toes.