Further clinical and molecular delineation of the 9q subtelomeric deletion syndrome supports a major contribution of EHMT1 haploinsufficiency to the core phenotype.

BACKGROUND: The 9q subtelomeric deletion syndrome (9qSTDS) is clinically characterised by moderate to severe mental retardation, childhood hypotonia and facial dysmorphisms. In addition, congenital heart defects, urogenital defects, epilepsy and behavioural problems are frequently observed. The syndrome can be either caused by a submicroscopic 9q34.3 deletion or by intragenic EHMT1 mutations leading to haploinsufficiency of the EHMT1 gene. So far it has not been established if and to what extent other genes in the 9q34.3 region contribute to the phenotype observed in deletion cases. This study reports the largest cohort of 9qSTDS cases so far. METHODS AND RESULTS: By a multiplex ligation dependent probe amplification (MLPA) approach, the authors identified and characterised 16 novel submicroscopic 9q deletions. Direct sequence analysis of the EHMT1 gene in 24 patients exhibiting the 9qSTD phenotype without such deletion identified six patients with an intragenic EHMT1 mutation. Five of these mutations predict a premature termination codon whereas one mutation gives rise to an amino acid substitution in a conserved domain of the protein. CONCLUSIONS: The data do not provide any evidence for phenotype-genotype correlations between size of the deletions or type of mutations and severity of clinical features. Therefore, the authors confirm the EHMT1 gene to be the major determinant of the 9qSTDS phenotype. Interestingly, five of six patients who had reached adulthood had developed severe psychiatric pathology, which may indicate that EHMT1 haploinsufficiency is associated with neurodegeneration in addition to neurodevelopmental defect.

Long-term metabolic consequences of switching from protease inhibitors to efavirenz in therapy for human immunodeficiency virus-infected patients with lipoatrophy.

The roles of nucleoside analogues and protease inhibitors (PIs) in the development of metabolic complications and fat-distribution abnormalities associated with highly active antiretroviral therapy (HAART) are not well known. We performed an observational study in which efavirenz was substituted for a PI for 41 patients receiving HAART who had prolonged virus suppression, clinical signs of severe lipoatrophy, hyperlipidemia, and insulin resistance. Clinical follow-up was performed for 1 year. Virus suppression was maintained in most of the patients, and a significant increase in CD4(+) lymphocyte count was observed, but no change in lipid profile or insulin resistance was observed. Abdominal fat content did not change, and subcutaneous fat depletion was even more pronounced >1 year after the switch. We conclude that, for PI-treated patients who present with lipoatrophy, hyperlipidemia, and insulin resistance, substituting efavirenz for PIs can maintain virus suppression and immunologic response to HAART, but it does not improve the lipid profile or resolve insulin resistance or lipoatrophy.