Seckel Syndrome

At a glance

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.

Synonyms

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

History

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

Incidence

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.

Genetic inheritance

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

Pathophysiology

Underlying genetic polymorphism: Mutation in the gene encoding ataxia-telangiectasia and RAD3-related (ATR) protein, which maps to chromosome 3q22.1-q24, the SCKL2 gene on 18p11.31-q11.2 for RBBP8, the SCKL3 gene in 14q23q24 and SCKL4 and SCKL5. Encoded proteins provide deoxyribonucleic acid (DNA) stability.

Diagnosis

Clinical supported by imaging of the brain with cerebral atrophy, gyral simplification, subarachnoid dilatation.

Clinical aspects

Four criteria are diagnostic: (1) Congenital harmonious dwarfism and postnatal growth retardation, (2) Facial dysmorphism: small head, large eyes, beak-like nose, narrow face, and receding mandible, dental malocclusion, (3) Mental retardation, and (4) Microcephaly with agenesis of the corpus callosum, dysgenetic cerebral cortex, and cerebral cysts. Other abnormalities include blood (anemia, pancytopenia), cleft lip/palate, (kypho) scoliosis and laryngeal stenosis.

Precautions before anesthesia

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.

Anesthetic considerations

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.

Pharmacological implications

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.

Other conditions to be considered

• ☞Cephaloskeletal Dysplasia (Majewski Osteodysplastic Primordial Dwarfism Type I): 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 ...