Hallermann syndrome is a congenital disease characterized mainly by facial and skull abnormalities. A short head, beak-like nose, malformed teeth, and cataracts are the distinctive symptoms. Intellectual disability is rare in this medical ailment.
Hallermann syndrome (HS) or Hallermann-Streiff syndrome (also called Francois dyscephalic syndrome) is a rare disease with characteristic craniofacial abnormalities. The most prominent are brachycephaly and pinched nose, giving the face a bird-like look. There are many other problems, including ocular and dental defects. Based on a number of cases, Francois   identified seven signs, most of which occur in the large majority of cases. These are the following: malformation of the head and face and bird-like appearance, dental irregularities, hypotrichosis, atrophy of the skin especially around the nose, bilateral microphthalmia, bilateral congenital cataracts, and proportionate nanism.
Apart from the shortness of the head, a prominent forehead is often observed. The nasal bones are prominent and beaked. The lower jaw is frequently small, and the chin is receding. Underdevelopment of the jaw and nasal cartilage, small nostrils, and the retraction of the tongue may lead to obstruction of the upper airway. A narrowed upper respiratory tract may cause a number of complications, especially in the newborns; the latter may be serious and include sleep apnea, respiratory embarrassment, airway infections, and anesthetic risk . These may even induce death . Tracheomalacia can occur, resulting in respiratory insufficiency and death .
The frequent ocular problem in affected people is congenital cataracts; these may clear up spontaneously over time. There are several other abnormalities in addition to the microphthalmia mentioned by Francois, such as corneal stromal opacities, ptosis, strabismus, nystagmus and others. Various dental problems are also characteristic of HS. The roots are inadequately developed, resulting in early loss of permanent teeth and partial crowns. Other malformations and absence of teeth may be noticed. Preventative dental care is imperative. The skin on the face, mainly in the area of the nose tends to be atrophic. Fat grafting has been shown to improve the condition of the skin as well as help cure breathing problems .
Only about 15 percent of those affected by HS have intellectual disabilities. The occurrence of the disease is sporadic . A female patient with two normal children has been reported, with altogether three cases of unaffected children being born to affected mothers .
Although symptoms of HS are striking, some of them can be seen in cases of progeria or progeroid conditions. Thus, differential diagnosis is important. Francois did not just describe the signs characterizing the disorder, but also listed those that have to be excluded. These are auricular and palpebral irregularities, early arteriosclerosis, arthrosis, muscular atrophy, nail and extremity anomalies, and mental retardation, all of which are associated with some other disease that resembles HS  .
Skeletal defects in HS can be characterized by radiological observations and may help in the diagnosis. The skull appears poorly ossified, and there is an increase in the Wormian bones. Although the skull is large, the middle of the face is underdeveloped. The gonial angle tends to be nearly straight. The nasal bone is pronounced and the teeth are small. The long bones show these features: they are unusually thin, the radius and ulna are bowed, and the metaphyseal ends are wide. The vertebral bodies appear small and flat .