Joseph A. Church

Adhesion of cells to the extracellular matrix (ECM) must be exquisitely coordinated to enable development and tissue homeostasis. Cell–ECM interactions are regulated by multiple signalling pathways that coordinate the activation state of the integrin family of ECM receptors. The protein talin is pivotal in this process, and talin’s simultaneous interactions with the cytoplasmic tails of the integrins and the plasma membrane are essential to enable robust, dynamic control of integrin activation and cell–ECM adhesion. Here, we report the identification of a de novo heterozygous c.685C>T (p.Pro229Ser) variant in the TLN1 gene from a patient with a complex phenotype. The mutation is located in the talin head region at the interface between the F2 and F3 domains. The characterization of this novel p.P229S talin variant reveals the disruption of adhesion dynamics that result from disturbance of the F2–F3 domain interface in the talin head. Using biophysical, computational and cell biological techniques, we find that the variant perturbs the synergy between the integrin-binding F3 and the membrane-binding F2 domains, compromising integrin activation, adhesion and cell migration. Whilst this remains a variant of uncertain significance, it is probable that the dysregulation of adhesion dynamics we observe in cells contributes to the multifaceted clinical symptoms of the patient and may provide insight into the multitude of cellular processes dependent on talin-mediated adhesion dynamics.

Int22h1/int22h2-mediated Xq28 duplication syndrome is caused by ~0.5 Mb chromosomal duplications mediated by nonallelic homologous recombination between intron 22 homologous region 1 (int22h1) and 2 (int22h2), which, in addition to int22h3, are also responsible for inversions disrupting the F8 gene in hemophilia A. This syndrome has recently been described in 9 males with cognitive impairment, behavioral problems, and distinctive facial features; and 6 females with milder phenotypes. The reciprocal deletion was previously reported in a mother and daughter. It was suggested that this deletion may not have phenotypic effects in females because of skewed chromosome X inactivation, but may be embryonic lethal in males. Array comparative genomic hybridization analyses were performed using oligonucleotide-based chromosomal microarray. Chromosome X inactivation studies were performed at the AR (androgen receptor) and FMR1 (fragile X mental retardation 1) loci. We present here 5 males and 6 females with int22h1/int22h2-mediated Xq28 duplication syndrome. The males manifested cognitive impairment, behavioral problems, and distinctive facial features. Two of the six females manifested mild cognitive impairment. This duplication was maternally inherited, and skewed chromosome X inactivation was observed in the majority of females carrying the duplication. We also report the reciprocal deletion in a mother and daughter with overweight, but normal cognition. In addition, we present the first case of a prenatally diagnosed de novo int22h1/int22h2-mediated deletion in a healthy female infant. We reviewed individuals previously reported with similar or overlapping rearrangements and evaluated the potential roles of genes in the rearrangement region. The similarity of clinical features among individuals with the int22h1/int22h2-mediated Xq28 duplication supports the notion that this duplication causes a recognizable syndrome that affects males with females exhibiting milder phenotypes. It is suggested that the observed cognitive impairment in this syndrome results from increased dosage of RAB39B gene located within the duplicated region. Increased dosage of CLIC2 may also contribute to the phenotype. The reciprocal deletion results in skewed chromosome X inactivation and no clinical phenotype in females. Review of overlapping deletions suggests that hemizygous loss of VBP1 may be the cause for the proposed male lethality associated with this deletion.

Patients with antibody deficiency rely on immunoglobulin products for protection against many vaccine-preventable diseases. We measured antibody titers against Bordetella pertussis and Neisseria meningitidis in patients receiving immunoglobulin (IG) therapy to determine if they have any protection against infections from these organisms. In an unblinded, prospective assessment we measured antibody titers against B. pertussis filamentous hemagglutinin (FHA) and pertussis toxin (PT) antigens and N. meningitidis serogroups A, C, W-135, and Y in patients receiving immunoglobulin therapy for primary immune deficiency (PI). We measured steady state levels in patients receiving subcutaneous immunoglobulin therapy while in patients receiving intravenous immunoglobulin therapy we measured titers immediately before and after infusion to more clearly define the contribution of the infused product. Thirty subjects, 17 females and 13 males, participated in the study, 22 were receiving intravenous IG products and 8 were receiving subcutaneous IG products. Diagnoses included common variable immunodeficiency in 12, combined immunodeficiency in 6, specific antibody deficiency in 6, X-linked agammaglobulinemia in 4 and ataxia telangiectasia and hyper-IgE syndrome in one each. All subjects had detectable IgG antibodies against the pertussis antigens measured and most had antibody to the meningococcus serotypes measured. However, only 26.6 % had protective levels (>= 2 mcg/mL) against serogroup C at trough or steady state. Patients receiving immunoglobulin therapy have antibodies against B. pertussis and most of them have antibodies against the four measured serogroups of N. meningitidis. There is significant variability in the levels of antibody between patients and the low titers against group C may suggest a role for active immunization in those who may respond to conjugated polysaccharide vaccine administration.

Purpose Adenitis for which no causative organism can be isolated is a common occurrence in patients with chronic granulomatous disease (CGD). Here we identify Acidomonas methanolica as a pathogen associated with adenitis in a patient with CGD. Methods The causative pathogen was obtained after prolonged incubation of an excised lymph node in thioglycolate broth. Identification was carried out by sequencing the 16s rRNA. Immunoblots were prepared utilizing protein extracts from the case patient’s A. methanolica isolate, an ATCC type strain of A. methanolica and G. bethesdensis. Results Fastidious gram-negative rods grew after prolonged incubation of an excised lymph node in thioglycolate broth. Sequencing of the 16s rRNA identified the organism as A. methanolica. Immunoblot confirmed the pathogen’s role in the patient’s adenitis by showing the patient’s specific immune response to the organism. Conclusions A. methanolica is the second member of the family, Acetobacteaceae to be associated with adenitis in patients with CGD.

Defects in innate immune responses appear to predispose to inflammatory bowel disease (IBD) similar to Crohn's disease (CD), and 30% of patients with chronic granulomatous disease (CGD), a genetic disease of the innate immune system, develop IBD. Antibody panels are used to assist in the diagnosis of IBD in symptomatic patients. The aim of this study was to determine the usefulness of serologic testing for IBD in children with CGD. The medical records of 9 patients with CGD were reviewed for symptoms of IBD, and a serologic panel for IBD was performed. The panel measures ASCA IgA and IgG ELISA, Anti-Omp C IgA ELISA, Anti-CBir 1 ELISA, and IBD-specific pANCA. A proprietary formula is used to report IBD likely. All 9 patients had IBD serologic findings consistent with CD; nevertheless, only 2 of the 9 patients had IBD symptoms: diarrhea and mucoid stools in one, and mild diarrhea and growth failure in the other. Endoscopy performed in these 2 patients revealed granulomatous colitis in one individual only. These findings indicate that IBD serologic testing does not identify CGD patients with IBD. The consistently positive IBD panels in our CGD patients suggest that this innate immune deficiency predisposes to antigen sensitization that is seen in CD. However, other factors appear to determine which CGD patients progress to clinical granulomatous IBD.

Church's case report is a reminder that "pediatric" genetic diseases are not limited to children.

Enfuvirtide, a peptide inhibitor of human immunodeficiency virus (HIV)-1-host cell membrane fusion, is the first of a new class of antiretroviral agents, the entry inhibitors. The safety and antiretroviral activity of enfuvirtide treatment of 24 weeks in HIV-1-infected children has been previously documented. Here we present the long term tolerability and safety of enfuvirtide. Fourteen children, 4 to 12 years of age, with incompletely suppressed HIV-1 infection were evaluated. Enfuvirtide was administered twice daily by subcutaneous injection. After the first 24 weeks of enfuvirtide dosing, subjects were evaluated every 8 weeks up to 96 weeks of therapy. At each visit, each subject had a physical examination and an assessment for adverse events with particular attention to evaluation of injection site reactions. Laboratory studies obtained at each visit included hematology and blood chemistry values, plasma HIV-1 RNA concentrations and CD4+ T cell counts. Of 14 subjects, 6 completed at least 96 weeks of treatment. One child discontinued enfuvirtide after 22 days of treatment because of an aversion to injections, and 1 child electively discontinued after week 24 because of surgical complications unrelated to study drug. Four subjects discontinued study because of virologic failure, defined as an increase or persistence of plasma HIV-1 RNA 1.0 copies/mL above baseline, which occurred between ≥log10 weeks 40 and 63. Two children experienced grade 3 adverse events resulting in discontinuation of the study drug; 1 subject developed grade 3 thrombocytopenia and 1 developed grade 3 edema at weeks 65 and 77, respectively. Eleven of 14 children had local injection site reactions during the first 24 weeks of treatment, 4 of the 12 subjects who continued treatment beyond week 24 reported local reactions. Generally, these local reactions were 1- to 3-cm tender nodules that developed after the injections and lasted for 1–2 days. Twelve children developed new diagnoses during treatment with enfuvirtide. None was judged to be definitively related to the study drug. Thirty-six percent of children starting enfuvirtide had HIV-1 RNA levels > 1 log10 copies/mL below baseline levels at week 96. Children remaining on enfuvirtide for the entire 96 weeks had a median of 65 cells/mm3 and 9% increase in CD4+ T cells. Enfuvirtide was generally safe and, except for a high rate of injection site reactions, well-tolerated in HIV-1-infected children for as long as 96 weeks.

Entry inhibitors, a new class of antiretroviral agents, interfere with the attachment, coreceptor interaction or fusion of HIV-1 with host target cells. The fusion inhibitor T-20 is the first in this new class, and the present study is the first to examine chronic sc administration of T-20 to HIV-1-infected children. Fourteen children, 4 to 12 years of age, with incompletely suppressed HIV-1 were studied. The median plasma viral load at baseline was 26 866 copies/ml (4.4 log10), and the median CD4 count was 523 cells/mm3. T-20 was administered twice daily by sc injection at 30 or 60 mg per m2 of body surface area per dose. For 7 days T-20 was added to the patients’ background antiretroviral regimens; at Day 7 each subject’s background therapy was changed to a regimen that was predicted to be virologically active, while T-20 was continued. Results are presented for the first 24 weeks of chronic T-20 dosing. T-20 was generally well-tolerated. One child discontinued the drug because of aversion to injections, but no child discontinued because of adverse events. Eleven (79%) of 14 children had local injection site reactions at some time during the chronic T-20 dosing. Eleven of 14 subjects achieved the protocol-specified milestone of at least a 0.7-log10 reduction in plasma HIV-1 RNA by Day 7. In 10 subjects (71%) virologic suppression of 1.0 log10 or greater was achieved at 24 weeks; 6 subjects (43%) had viral loads <400 copies/ml and 3 (21%) had fewer than 50 copies/ml at 24 weeks. These results indicate that a 24-week regimen of twice daily sc dosing of T-20 in HIV-1-infected children is safe and tolerable and that it is associated with suppression of HIV-1 replication during 24 weeks of administration.