There is frequently a delay in the ossification of the nose bones (Figs. 4.1 and 4.2), the forehead could be domed, sometimes with a prefrontal edema (Fig. 4.3), the features could appear flat without the upper facial angle truly being modified (Figs. 4.4 and 4.5a, b), the mouth is small, with corners that to not exceed the wings of the nose (Fig. 4.6a, b), the palpebral fissures are directed up and behind (Fig. 4.7), the ears are small and low (Fig. 4.8), and the tongue could be protrusive (Fig. 4.9).

Nevertheless, in a certain number of cases, the profile could appear normal (Fig. 4.10).

The diagnosis of this chromosomal anomaly is usually based on a collection of morphological anomalies.

In these case, the dysmorphism associates microretrognathia, sloping forehead, and small low ears. Cleft palate is frequent (cf. Clefts)

Dysmorphism in the case of trisomy 13 is often very spectacular, covering a wide range of possibilities from a simple median incisor (Fig. 4.15) to cyclopia (Figs. 4.16 and 4.17), with a full range of intermediary aspects possible including more or less hypotelorism (Fig. 4.18), single nostrils (Figs. 4.18, 4.19, and 4.20). Clefting is found in 60–80 % of cases, and is both unilateral and bilateral. Median clefts are characteristic (Figs.4.21 and 4.22).

These anomalies are related to cerebral medial line anomalies (alobar, semi-lobar or lobar holoprosencephaly) that are present in 50 % of cases.

Facial dysmorphism related to other chromosomal anomalies are often rougher, as seen in the below examples corresponding to:

Wolf-Hirschhorn syndrome results from a microdeletion, with an incidence of 1/50,000. The deletion occurs on the short arm of chromosome 4 at the 4p.16.3 region. This deletion is sporadic in the majority of cases. Research for this deletion should be signaled to geneticists when they test the amniotic fluid.

The dysmorphism is characteristic:

This dysmorphism occurs in a context of early IUGR with, in particular, severe microcephaly, mental retardation could be severe with walking and language acquisition occurring more or less late.

These anomalies, resulting from the premature fusing of one or several sutures, often lead to severe dysmorphism. The overall incidence is estimated at 1/2000 and around 100 different forms have been described. The role of an ultrasonographer consists of labeling as best as possible the type of anomaly and then looking for other markers to determine whether or not the craniostenosis is related to a syndrome. It is useful to remember that the first sign signaling craniostenosis could be an enlargement of a healthy contralateral suture.

Craniostenoses are classified based on the type of suture involved (Figs. 4.27, 4.28, 4.29, and 4.30).

Below are a few examples of an approach to these complex pathologies.

Achondroplasia is the most frequent osteochondrodysplasia, with an estimated frequency between 1/15,000 and 1/26,000. It is related to a mutation of the FGFR3 gene. This bone pathology becomes apparent starting at 26 gestational weeks, the diagnosis most frequently made during the third trimester ultrasound showing very short limbs, in particular rhizomelia contrasting with macrocrania (very marked frontal bossing), and a relatively narrow thorax (Fig. 4.45). In addition to these markers, the ultrasound will show a characteristic appearance of the upper femoral metaphyses, which appear to be slender like “ice cream cones,” leading to an “opening” of the upper femoral angle (Fig. 4.44), short trident hands, and platyspondyly (Fig. 4.45).

Dysmorphism combines marked frontal bossing and a very “hollowed” nasal bridge with an abnormally closed upper facial angle (Figs. 4.46, 4.47, 4.48, and 4.49).

This anomaly has an estimated incidence of 1/10,000, but is probably underestimated. A few family recurrences suggest autosomal recessive transmission or low-penetrating dominance. Binder-like dysmorphism can be found in cases of mothers taking phenytoin and anti-vitamin K type anticoagulants, or with lupus.

This sequence is considered to be an allelic variation of punctate chondrodysplasias.

Dysmorphism takes the form of a flattened midface that translates into an abnormally open upper facial angle, a short nose with a flattened root, a slightly protruding mandible, and a little developed upper maxilla (Figs. 4.50, 4.51, 4.52, 4.53, and 4.54). Tests should include karyotype, maternal blood test for lupus, a detailed ultrasound looking for punctate epiphyses (Figs. 4.55 and 4.56), a scan could be done to confirm the ultrasound results. Discovery of a brachytelephalangy would suggest a benign form of chondrodysplasia punctate (Fig. 4.57).

This is the most frequent of fatal osteochondrodysplasias, with an estimated 1/20,000 to 1/60,000.

Currently, a diagnosis is made most often during the first trimester, although it could be made during the second trimester. It combines very short limbs with femurs shaped like old-fashioned telephone receivers, a narrow thorax that looks like a champagne cork on a sagittal view, platyspondyly with H-shaped vertebrae, and macrocrania. Hydramnios is common (Fig. 4.58).

Dysmorphism is marked by macrocrania, mid-face hypoplasia translated by a marked nasal bridge with a reduced upper facial angle (Figs. 4.59, 4.60, 4.61, and 4.62).

This rare syndrome affects between 1/10,000 and 1/25,000 births, its origin being a genetic deletion on the paternal chromosome 15 (at 15q11-q13). It is:

Prader-Willi syndrome is considered with the discovery of hydramnios and slow growth related to diminished active movements, fetal cardiac disorders, and genital anomalies, and a detailed study of the face could then support the hypothesis.

Dysmorphism in this syndrome is characterized by: