Juvenile dermatomyositis in association with 22q11.2 deletion syndrome

Histology of the pharyngeal constrictor muscle in 22q11.2 deletion syndrome and non-syndromic children with velopharyngeal insufficiency

Plastic surgeons aim to correct velopharyngeal insufficiency manifest by hypernasal speech with a velopharyngoplasty. The functional outcome has been reported to be worse in patients with 22q11.2 deletion syndrome than in patients without the syndrome. A possible explanation is the hypotonia that is often present as part of the syndrome. To confirm a myogenic component of the etiology of velopharyngeal insufficiency in children with 22q11.2 deletion syndrome, specimens of the pharyngeal constrictor muscle were taken from children with and without the syndrome. Histologic properties were compared between the groups. Specimens from the two groups did not differ regarding the presence of increased perimysial or endomysial space, fiber grouping by size or type, internalized nuclei, the percentage type I fibers, or the diameters of type I and type II fibers. In conclusion, a myogenic component of the etiology of velopharyngeal insufficiency in children with 22q11.2 deletion syndrome could not be confirmed.

Maturational alterations of peripheral T cell subsets and cytokine gene expression in 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome is a common disorder characterized by thymic hypoplasia, conotruncal cardiac defect and hypoparathyroidism. Patients have a risk of infections and autoimmunity associated with T lymphocytopenia. To assess the immunological constitution of patients, the numerical changes and cytokine profile of circulating T cells were analysed by flow cytometry and real-time polymerase chain reaction (PCR). CD3+, CD4+, T cell receptor (TCR)alphabeta+ or CD8alphaalpha+ cell counts were lower, and CD56+ cell counts were higher in patients than in controls during the period from birth to adulthood. The ageing decline of CD3+ or CD4+ cell counts was slower in patients than in controls. The proportion of CD8alphaalpha+ cells increased in controls, and the slope index was larger than in patients. On the other hand, both the number and proportion of Valpha24+ cells increased in patients, and the slope indexes tended to be larger than in controls. The positive correlation of the number of T cells with CD8alphaalpha+ cells was observed only in patients, and that with Valpha24+ cells was seen only in controls. No gene expression levels of interferon (IFN)-gamma, interleukin (IL)-10, transforming growth factor (TGF)-beta, cytotoxic T lymphocyte antigen 4 (CTLA4) or forkhead box p3 (Foxp3) in T cells differed between patients and controls. There was no significant association between the lymphocyte subsets or gene expression levels and clinical phenotype including the types of cardiac disease, hypocalcaemia and frequency of infection. These results indicated that T-lymphocytopenia in 22q11.2 deletion patients became less severe with age under the altered composition of minor subsets. The balanced cytokine profile in the limited T cell pool may represent a T cell homeostasis in thymic deficiency syndrome.