*4.1.2. Proboscis*

opacity of the lens. Usually, the bilateral lesions are generally syndromic, with a poor prognosis; as for unilateral lesions, they are generally linked to a fetal infection. The genetic aspect of

**Associated abnormalities:** there is not any high risk of chromosomal abnormalities. It is in only 10% of the cases that genetic syndromes are found, and these include the chromosomal defects. In about 10% of the cases, genetic syndromes are found, and the most common include: Walker-Warburg syndrome and chondrodysplasia punctata. Only a fifth of the congenital cataracts cases are linked to infections such as rubella, toxoplasmosis, or CMV [20].

**Prognosis:** Usually good for isolated cases. Postpartum ophthalmologic surgeries have good results, which do not affect the quality of life. Prognosis is quite poor for syndromic cataract,

The most frequent clinical characteristic in diagnosing the Down syndrome has been the short ear length. Sonographic studies implied that measurements of the short ear length could be a useful predictor of fetal anomalies. In late gestation, important details of the anatomy of the external ear became accessible. In good conditions for scanning, and using high-resolution systems, the helix, scaphoid fossa, triangular fossa, concha, antihelix, tragus, antitragus, inter-

A small nose is very commonly seen during postnatal examination of fetuses or neonates who also present trisomy 21 as well as for more than 40 other genetic problems. The nasal bone can be measured using a mid-sagittal profile for normal singleton fetuses between the 14th and 34th week of gestation. Thus, the length of the nasal bones increase from 4 mm at 14 weeks to 12 mm at 35 weeks gestation. A possible improvement in screening for trisomy 21 by examining the fetal nasal bone with ultrasound at 11–14 weeks of gestation has been considered [22].

**Etiology:** Unknown. It can either be an isolated malformation or be part of a malformation complex, such as holoprosencephaly or mandibulofacial dysostosis (Treacher Collins syndrome) [23]. **Embryology:** Around the 6th week of gestation, the primitive nasal and oral cavities communicate freely using an opening, which will close progressively when the palate starts developing.

cataracts can be linked to microphthalmia.

102 Congenital Anomalies - From the Embryo to the Neonate

though.

**3. The ear**

**Investigations:** ultrasound, karyotyping, array and TORCH.

tragic incisure, and lobule are sometimes visualized [21].

**4. The nasal bone and nostrils**

**4.1. Anomalies of the nose**

**Definition:** Absence of the nose.

*4.1.1. Arhinia*

**Definition:** A proboscis is a trunk-like appendage, with one or two internal openings, and it is usually associated with the absence of the nose.

**Incidence:** Cyclopia and cebocephaly, two of the main conditions for a proboscis to be present, occur in 1:40,000 and 1:16,000 births, respectively [26].

**Embryology:** The presence of a proboscis is frequently associated with holoprosencephaly. Apparently, a primary disorder in the prechordal mesenchyma develops into an abnormal induction of the midfacial structures. If the nasal prominences develop abnormally, this may lead to a fusion of the olfactory placodes and to the formation of a proboscis [27].

**Pathology and associated anomalies:** Usually there is a single central opening in the proboscis, and it does not have any connection to the choanae. The ethmoid, the nasal conchae, and the nasal and lacrimal bones are absent. Usually, in cyclopia, ethmocephaly, and cebocephaly, the cleft of the lip and the palate are absent. The presence of a proboscis is seldom found in the absence of holoprosencephaly. In rare cases, a bilateral proboscis can be noticed [28].

**Diagnosis:** The diagnosis relies on the demonstration of a trunk-like structure, usually with a single central opening either occupying the normal position of the nose or hanging above the orbits [29] (**Figure 8**).
