Seckel Syndrome

Syndrome involving a form of primordial dwarfism with a characteristic facial-head shape (“bird-headed” appearance) and spongioid microcephaly (called also the Chimpanzee brain). Other clinical features include large ears, sparse hair, joint defects, clubfoot, trident hands and mental retardation.

Bird-Headed Dwarfism; Nanocephalic Dwarfism; Microcephalic Primordial Dwarfism; Harper Syndrome; Seckel Nanism; Virchow-Seckel Syndrome.

First described in 1960 by Helmut Paul George Seckel, German pediatrician.

Extremely rare; about 40 cases in the literature. Clinical delineation has been inconsistent and probably only one-third of reported cases are truly affected and only seven familial cases have been reported.

Autosomal recessive inheritance. Chromosome instability has been seen in a small subgroup of patients.

Seckel syndrome may be caused by a mutation in the gene encoding ataxia-telangiectasia and RAD3-related protein, which maps to chromosome 3q22.1-q24. Another locus for Seckel syndrome has been mapped to chromosome 18p11-q11. Central nervous system anomalies suggest an underlying neuronal migration disorder.

Clinical supported by imaging of the brain.

Dwarfism, low birth weight. Small head, large eyes, beak-like nose, narrow face, and receding mandible. Laryngeal stenosis. Mental retardation, very small brain with agenesis of the corpus callosum, dysgenetic cerebral cortex, cerebral cysts. Pancytopenia.

Assessment of airway must be conducted for possible difficult tracheal intubation. The presence of laryngeal stenosis must be eliminated using imaging if indicated. Case report of intraoperative abnormal hypertension suggests that renal examination and imaging must be performed.

Direct laryngoscopy and tracheal intubation are usually not difficult, however, the potential for laryngeal stenosis requires that smaller than predicted endotracheal tubes must be available. It is recommended to monitor the arterial blood pressure invasively because of the significant risk of severe hypertension.

There are no abnormal responses to drugs reported. Also, patients are not known to have greater sensitivity to narcotics even in presence of severe microcephaly.

Cephaloskeletal Dysplasia (Osteodysplastic Primordial Dwarfism Type I): An extremely rare inherited disorder characterized by low birth weight, dwarfism, microcephaly, and “beak-like” protrusion of the nose. Other characteristic facial features include abnormally large eyes, micrognathia, retrognathia, a narrow face, and low-set ears. Affected children may exhibit mental retardation. This condition closely resembles Seckel syndrome, except that, in Cephaloskeletal Dysplasia, the body proportions are abnormal and the limbs are unusually short and bowed. In Seckel syndrome, the proportions are normal. It is suggested that the inheritance is an autosomal recessive trait.

Osteodysplastic Bird-Headed Dwarfism Type II (Osteodysplastic Primordial Dwarfism Type II): An extremely rare inherited disorder characterized by severe dwarfism, microcephaly, “beak-like” nose, and various skeletal abnormalities especially the arms and legs. Low birth weight may be present. Other clinical features include retrognathia, a narrow face, and dysplastic ears. Mental retardation may also be present. It is inherited as an autosomal recessive transmission.

Osteodysplastic Bird-Headed Dwarfism Type III (Osteodysplastic Primordial Dwarfism Type III): Characterized by short stature, microcephaly, and a “beak-like” nose. Retrognathia, a narrow face, receding forehead, and alopecia have been reported. Some affected individuals may exhibit skeletal deformities. It is inherited as an autosomal recessive transmission.

Hallermann-Streiff Syndrome: A rare inherited disorder characterized by dwarfism, craniofacial anomalies, a “beak-like” nose, microcephaly that may appear brachycephalic, malar hypoplasia, micrognathia, hypoplasia of the mandible, and cleft lip/palate. The eye abnormalities may include strabismus, nystagmus, cataracts, microphthalmia, and blue sclera. Affected individuals may show sparse hair on the scalp and body (hypotrichosis), dental abnormalities, and skin atrophy, especially on the nose and scalp. Most cases appear to be sporadic.