Syndromic microphthalmia-9 (MCOPS9), also referred to as pulmonary hypoplasia-diaphragmatic hernia-anophthalmia-cardiac defect, is characterized by bilateral clinical anophthalmia, pulmonary hypoplasia/aplasia, cardiac malformations, and diaphragmatic defects. The phenotype is variable, ranging from isolated clinical anophthalmia or microphthalmia to complex presentations involving the cardiac, pulmonary, diaphragmatic, and renal systems. At its most severe, infants are born without pulmonary structures and die soon after birth (Marcadier et al., 2015).

Syndrome that has characteristics of female to male sex reversal and developmental anomalies of the kidneys, adrenal glands and lungs. The syndrome is lethal and has been described in three fetuses. It is caused by homozygous missense mutations in the WNT4 gene. It is transmitted as an autosomal recessive trait.

The Mardini-Nyhan association comprises uni- or bilateral lung agenesis, complex cardiac defects, particularly total anomalous pulmonary venous return (TAPVR), and thumb abnormalities (summary by Hastings et al., 2009).

Tetraamelia syndrome-2 (TETAMS2) is characterized by rudimentary appendages or complete absence of the limbs, usually symmetric, as well as bilateral agenesis of the lungs. There are abnormalities of the pulmonary vasculature and dysmorphic features, including bilateral cleft lip/palate, ankyloglossia, mandibular hypoplasia, microretrognathia, and labioscrotal fold aplasia (Szenker-Ravi et al., 2018). For a discussion of genetic heterogeneity of TETAMS, see 273395.