18q‐ syndrome and ectodermal dysplasia syndrome: Description of a child and his family

Abstract

The 18q- syndrome [MIM #601808] is a terminal deletion of the long arm of chromosome 18. The most common deletion extends from region q21 to qter. We report here a nine-year-old boy possessing a simple 18q- deletion who had abnormalities of the brain, skull, face, tooth, hair, bone, and skin, plus joint laxity, tongue palsy, subtle sensoneural deafness, mental and speech delay, attention deficit hyperactivity disorder (ADHD), tic, and restless legs syndromes. His karyotype was 46, XY, del (18)(q21.31-qter). The size of the deletion was approximately 45 cM. Most of these abnormalities were not explained by the 18q- deletion. The family pedigree suggested the presence of a subtle involvement of ectodermal and/or mesodermal structures. Karyotypes of the other family members were normal.

Cortical periventricular heterotopia with ectodermal dysplasia

“…Such replication of observations strengthens confidence that the new findings were not likely due to chance or some ''quirk'' of an individual case. From this point of view, Zannolli et al [2002] found low central incisor agenesis, another very rare condition, in a man with subtle EDs.…”

Case report of de novo dup(18p)/del(18q) and r(18) mosaicism

“…To determine the critical region for the del(18q) syndrome, a genotype-phenotype correlation has been studied (Kline et al 1993;Brkanac et al 1998;Cody et al 1999). Zannolli et al (2003) described a patient with del(18) (q21.31-qter) who had ectodermal dysplasia syndrome with a wide spectrum of abnormalities and a family pedigree with normal karyotypes, suggesting its subtle involvement in the development of ectodermal and/or mesodermal structures. Stewart et al (2001) described another case of del (18)(q21.3) syndrome associated with harlequin ichthyosis, an autosomal recessive skin disorder, and speculated that the responsible gene may lie at or distal to 18q21.3.…”

“…Signals for chromosomes 11 (e-g, k) and 12 (h-j, l) were used as controls (green short-arm subtelomere, red long-arm subtelomere) described the presence of several less-common defects, such as brachycephaly, midface hypoplasia, coxa valga, and sparse hair. Zannolli et al (2003) suggested that complex mechanisms may be involved in diversification of the neural crest, endoskeletal elements, brain organization, and the organization of other body parts, such as bones and teeth. The patient in our study also had several congenital abnormalities, including missing teeth; canine impaction; skin, hair, and nail dysplasia; vertebral fusion; and other skeletal and osteoarticular abnormalities.…”

“…Congenital heart defects may also be found (Gorlin et al 1990;Sturm et al 2000). A variety of other features have been recorded, including cleft palate, eye abnormalities, downturned corners of the mouth, low-set ears and a low hair line (Gorlin et al 1990;Cody et al 1997;Gustavsson et al 1999;Zannolli et al 2003).…”

“…Hypothyroidism and hypogonadism occur less commonly. Pernicious anemia, ectodermal dysplasia, harlequin ichthyosis, autoimmune thyroiditis, and insulin-dependent diabetes mellitus also have been reported, albeit rarely (Dacou-Voutetakis et al 1999;Gustavsson et al 1999;Stewart et al 2001;Zannolli et al 2003). Immunoglobulin A (IgA) deficiency has been recorded in several instances (Hecht 1969).…”