Seckel syndrome. Seckel bird head syndrome.
Incidence
The syndrome is familial with parental consanguinity and is transmitted as an autosomal recessive trait.Multiple occurrence in the same sibship, increased frequency of parental consanguinity, occurrence in both sexes, and normal parents suggest autosomal recessive inheritance.
Clinical Characteristics
A syndrome of proportionate dwarfism, delayed mental development, microcephaly, and typical facial appearance marked by a birdlike protrusion of midfacial structures. Seckel syndrome, an autosomal recessive disorder is the most common of the microcephalic osteodysplastic dwarfisms. Seckel syndrome is characterized by a proportionate dwarfism of prenatal onset, a severe microcephaly with a bird-headed like appearance and mental retardation. Hematological abnormalities with chromosome breakage have only been found in 15 to 25% of patients. The differential diagnosis with microcephalic osteodysplastic dwarfism type II can only be made with a complete radiographic survey in the first years of life. Besides to a wide phenotypic heterogeneity between affected patients, genetic heterogeneity has also been proven, with three loci identified to date by homozygosity mapping: SCKL1 (3q22.1-q24, ataxia-telangiectasia and Rad3-related protein (ATR) gene), SCKL2 (18p11.31-q11.2, unknown gene) and SCKL3 (14q23, unknown gene). SCKL3 seems to be the predominant locus for Seckel syndrome. Mental retardation is usually severe and families should be helped for social problems. In case of associated hematological abnormalities (anemia, pancytopenia, acute myeloid leukaemia), medical treatment should be provided. In addition to dwarfism of 'low birth weight' type, the features are small head, large eyes, beak-like protrusion of the nose, narrow face, and receding lower jaw. Mental retardation is not as marked as might be expected in view of the very small brain. Multiple occurrence in the same sibship, increased frequency of parental consanguinity, occurrence in both sexes, and normal parents suggest autosomal recessive inheritance.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
It is a clinical diagnosis.