Phenotypic variability in patients with unique double homozygous mutations causing variant ataxia telangiectasia.

Ataxia-Telangiectasia (A-T) is a neurodegenerative disease caused by bi-allelic mutations in the Ataxia-Telangiectasia-Mutated (ATM) gene. Complete lack of ATM activity leads to severe A-T and mutations allowing for residual activity cause a milder phenotype, termed variant A-T. There are only sparse data on the variability in phenotypes of variant A-T patients carrying the same mutations. A retrospective study of 15 patients with variant A-T, all double homozygous for the same mutations was conducted. The age of first symptom ranged from 4-180 months, including: truncal ataxia at <18 months of age in 9 patients, ataxia and instability only during fever in one patient, dystonia in one patient and malignancy in 4 patients. Global developmental delay and occulo-motor apraxia were recorded in 4/14 patients. Variant A-T patients with the same mutations in ATM, have variable phenotypes. Environmental, epigenetic, and post translational factors are likely to play a role in creation of the phenotype in variant A-T patients.

Unusual phenotype in patients with a hypomorphic mutation in the DCLRE1C gene: IgG hypergammaglobulinemia with IgA and IgE deficiency.

The nuclease Artemis is a enzyme for V(D)J recombination allowing for the creation of T and B lymphocytes as well as for the repair of radiation-induced DNA double strand breaks encoded by the DCLRE1C gene. Artemis-null mutations are a known cause of severe combined immunodeficiencies (SCIDs) with radiosensitivity. Hypomorphic mutations in Artemis have been reported to cause a "leaky SCID"" phenotype, typically with hypogammaglobulinemia. We present four patients, all harboring the same unique hypomorphic mutation in the DCLRE1C gene, an 8-base pair insertion (c.1299_1306dup, p.Cys436*) presenting with a relatively mild phenotype including pulmonary infectious EBV-related lymphoproliferative diseases, an autoimmune phenomenon. Non-typical findings of IgG hypergammaglobulinemia accompanied by IgA and IgE deficiency were recorded in all patients. The typical viral, fungal, and opportunistic infections were absent, and patients reached a relatively old age.

Neutrophil Functions in Immunodeficiency Due to DOCK8 Deficiency.

Neutrophil chemotactic defects have been reported previously in patients with hyper-IgE syndrome. Bi-allelic mutations in dedicator of cytokinesis 8 (DOCK8) gene usually cause an autosomal recessive hyper-IgE syndrome phenotype. Data are lacking about expression of DOCK8 protein in neutrophils or the possible role of DOCK8 in neutrophil function. We sought to determine if DOCK8 protein is expressed in neutrophils and if DOCK8 plays a role in neutrophil function. The expression of DOCK8 protein was assessed in neutrophils from healthy volunteers with and without activators. Neutrophil chemotaxis, phagocytosis and superoxide generation were studied in neutrophils from DOCK8-deficient patients compared to neutrophils from healthy controls before and after stimulation with activators: phorbol 12-myristate 13-acetate (PMA) or N-Formylmethionyl-leucyl-phenylalanine (fMLP). DOCK8 protein is expressed in resting neutrophils from healthy controls, with a significant increase in DOCK8 expression after stimulation. Neutrophil functions were assessed in 6 DOCK8-deficient patients. All patients had the same non-sense mutation (c.C5134A, p.S1711X). Normal chemotaxis was recorded in 4/6 patients while a mild to moderate chemotaxis defect was recorded in 2/6. Superoxide generation was mainly normal in neutrophils from all six patients and phagocytosis was normal in five patients tested. We conclude that DOCK8 protein is expressed in resting human neutrophils and DOCK8 expression is increased after stimulation with either PMA or fMLP. Most patients with a disease-causing mutation in DOCK8 have normal neutrophil functions, while a minority showed a mild to moderate chemotactic defect.

Incidence of typically Severe Primary Immunodeficiency Diseases in Consanguineous and Non-consanguineous Populations.

PURPOSE: Primary immunodeficiency diseases are considered to be rare diseases; however, data on the exact birth incidences of these diseases are sparse. Southern Israel is inhabited by two major populations: a relatively non-consanguineous Jewish population and a highly consanguineous Muslim Bedouin population. We sought to calculate the incidences of typically severe primary immunodeficiency diseases and compare the incidences in these populations. METHODS: A retrospective analysis of all typically severe primary immunodeficiency diseases evaluated at a single center from January 1, 1996 to December 31, 2016. The amount of live births by population was the denominator for calculating the incidences by population. RESULTS: A total of 95 patients were included, 85 of Bedouin and 10 of Jewish ethnicities. There were 152,331 births in the Bedouin and 160,998 births in the Jewish populations. The total incidence of typically severe primary immunodeficiency diseases was higher in the Bedouin population than expected based on previous studies. The total incidences were 55.8/105 births in the Bedouin population compared with 6.2/105 births in the Jewish population (P < 0.001). The incidences of all combined immunodeficiency diseases, ataxia telangiectasia, and infantile IBD due to interleukin 10 receptor defects were all significantly higher in the Bedouin population (P < 0.001). The incidence of X-linked agammaglobulinemia was not significantly different between both populations (P = 0.11). CONCLUSIONS: Typically, severe primary immunodeficiency diseases are not rare diseases in a consanguineous population; these diseases are significantly more common in the Bedouin population. This finding is probably also applicable to other consanguineous populations, and in these populations, primary immunodeficiency diseases should not be regarded as rare diseases.

The clinical and laboratory spectrum of dedicator of cytokinesis 8 immunodeficiency syndrome in patients with a unique mutation.

Mutations in the dedicator of cytokinesis 8 (DOCK8) gene cause a combined immunodeficiency usually diagnosed as autosomal recessive hyper IgE syndrome. We sought to reveal the varying manifestations in patients with a unique mutation in DOCK8 gene by a retrospective medical record review. Ten patients from five consanguineous families and three tribes were included. Seven patients were homozygous for the c.C5134A, p.S1711X mutation, and the remaining three patients were their siblings manifesting hyper IgE syndrome features without a genetic diagnosis. Prior to the genetic diagnosis, the clinical diagnosis was "hyper IgE syndrome" in six patients and "anti-pneumococcal antibody deficiency," "recurrent pneumonia with bronchiectasis," and "asthma with hypereosinophilic syndrome" each diagnosed once. One additional patient was diagnosed due to family history. The age of presentation varied from 1 to 16 months. Eczema was diagnosed in all patients, food allergies in three, and severe herpes keratitis or malignancy or autoimmunity in two patients. Elevated IgE was recorded in nine patients; however, in six patients, the initial serum IgE concentration was equal to or less than three times the normal concentration for age, and in these patients, the median age at IgE evaluation was 7.5 months compared with 21.5 months in patients with an initial IgE concentration above three times the normal concentration for age (P = 0.067). The spectrum of disease manifestations in patients with a unique mutation in DOCK8 is variable. The genotype-phenotype correlations may be modified by genetic and/or epigenetic modifiers beyond the monogenic effect. Younger patients tend to have lower IgE concentrations at the initial measurement of IgE.

IL-12 receptor 1ß deficiency with features of autoimmunity and photosensitivity.

Primary immunodeficiences are often accompanied by autoimmune phenomena. IL-12 receptor deficiency is a well characterized primary immunodeficiency that leads to propensity to intracellular infections mainly with mycobacteria and Salmonella. We report on two patients with IL-12 receptor ß1 deficiency that presented with autoimmune manifestations and photosensitivity dermatitis and describe possible pathogenetic mechanisms leading to development of clinically significant autoimmune phenomena.

Subclinical intestinal inflammation in chronic granulomatous disease patients.

Chronic granulomatous disease is a primary immunodeficiency caused by impaired neutrophil production of reactive oxygen species. Non-infectious colitis is common in chronic granulomatous disease, and high levels of antimicrobial antibodies that are associated with Crohn's disease are common even without colitis. Fecal calprotectin concentration is a marker for intestinal inflammation. We sought to determine whether subclinical intestinal inflammation occurs in asymptomatic chronic granulomatous disease patients. Asymptomatic chronic granulomatous disease patients without overt gastrointestinal symptoms suggestive of colitis at the time of enrollment were studied for fecal calprotectin concentration, antibodies associated with Crohn's disease and systemic inflammatory markers. Eight patients were included, aged 54-176 months. In 7/8 (87.5 %) fecal calprotectin concentration was normal (<50) and elevated (137 mg/kg) in only one patient. This patient later developed colitis. In 7/8 (87.5 %) anti-Saccharomyces cerevisiae antibody was positive. C-reactive protein, albumin, complete blood count and p-anti-neutrophil cytoplasmic antibody were normal in all 8 patients. Subclinical colitis is not evident in most asymptomatic chronic granulomatous disease patients; however, in some patients, fecal calprotectin concentration may be elevated, possibly indicating the presence of subclinical colitis and predicting the occurrence of clinically relevant colitis. Serum anti-Saccharomyces cerevisiae antibody concentrations do not seem to correlate with fecal calprotectin concentration in asymptomatic chronic granulomatous disease patients.

The effects of Bruton tyrosine kinase inhibition on chemotaxis and superoxide generation in human neutrophils.

PURPOSE: The role of the Bruton tyrosine kinase (Btk) protein in neutrophil function has been evaluated using neutrophils from healthy volunteers after incubation with a Btk inhibitor, leflunomide metabolite analog (LFM-A13), suggesting an important role for Btk in neutrophil function. We sought to determine the role of Btk protein on neutrophil superoxide generation and chemotaxis stimulated by N-formyl-methionine-leucine-phenylalanine (fMLP). METHODS: Chemotaxis was assayed on agarose gel and superoxide generation by cytochrome C reduction. The affects of LFM-A13 on chemotaxis and superoxide generation in unstimulated and fMLP stimulated neutrophils were studied in Btk deficient neutrophils from XLA patients compared with matched controls analyzed simultaneously. RESULTS: Chemotaxis and stimulated superoxide production were similar in the normal and Btk deficient neutrophils and were similarly inhibited by LFM-A13. In one patient, LFMA13 had no effect on superoxide generation in Btk deficient neutrophils up to a concentration of 25 microM, while inhibited superoxide production by control neutrophils. CONCLUSIONS: Our results suggest that Btk does not have a specific role in neutrophil fMLP-stimulated superoxide generation and chemotaxis since these activities were similarly inhibited by LFM-A13 in Btk deficient and normal neutrophils. The lack of superoxide generation following Btk inhibition by LFM-A13 in Btk deficient neutrophils from one patient may suggest some heterogeneity in the role of Btk in fMLP induced neutrophil superoxide generation.

Clinical features of Candidiasis in patients with inherited interleukin 12 receptor ß1 deficiency.

BACKGROUND: Interleukin 12Rß1 (IL-12Rß1)-deficient patients are prone to clinical disease caused by mycobacteria, Salmonella, and other intramacrophagic pathogens, probably because of impaired interleukin 12-dependent interferon γ production. About 25% of patients also display mucocutaneous candidiasis, probably owing to impaired interleukin 23-dependent interleukin 17 immunity. The clinical features and outcome of candidiasis in these patients have not been described before, to our knowledge. We report here the clinical signs of candidiasis in 35 patients with IL-12Rß1 deficiency. RESULTS: Most (n = 71) of the 76 episodes of candidiasis were mucocutaneous. Isolated oropharyngeal candidiasis (OPC) was the most common presentation (59 episodes, 34 patients) and was recurrent or persistent in 26 patients. Esophageal candidiasis (n = 7) was associated with proven OPC in 2 episodes, and cutaneous candidiasis (n = 2) with OPC in 1 patient, whereas isolated vulvovaginal candidiasis (VVC; n = 3) was not. Five episodes of proven invasive candidiasis were documented in 4 patients; 1 of these episodes was community acquired in the absence of any other comorbid condition. The first episode of candidiasis occurred earlier in life (median age±standard deviation, 1.5 ± 7.87 years) than infections with environmental mycobacteria (4.29 ± 11.9 years), Mycobacterium tuberculosis (4 ± 3.12 years), or Salmonella species (4.58 ± 4.17 years) or other rare infections (3 ± 11.67 years). Candidiasis was the first documented infection in 19 of the 35 patients, despite the vaccination of 10 of these 19 patients with live bacille Calmette-Guérin. CONCLUSIONS: Patients who are deficient in IL-12Rß1 may have candidiasis, usually mucocutaneous, which is frequently recurrent or persistent. Candidiasis may be the first clinical manifestation in these patients.

A novel mutation in SCN9A in a child with congenital insensitivity to pain.

BACKGROUND: [corrected] Congenital insensitivity to pain (CIP) is a rare condition in which patients have no pain perception and anosmia but are otherwise essentially normal (OMIM 243000). The recent discovery of the genetic defects underlying 3 monogenic pain disorders has provided additional and important insights about some components of human pain. Genetic studies in families demonstrating recessively inherited channelopathy-associated insensitivity to pain have identified nonsense mutations that result in truncation of the voltage-gated sodium channel type IX subunit (SCN9A), a 113.5-kb gene comprising coding 26 exons. Here we describe a patient with CIP with a new mutation in SCN9A not described yet. METHODS: All exons were sequenced. RESULT: All 26 coding exons were sequenced and two changes were identified in homozygosity in exon 10: c.1126 A > C causing K376Q and c.1124delG causing p.G375Afs* frame shift. CONCLUSION: We report a novel, loss-of-function mutation in homozygosity that causes congenital insensitivity to pain and provide a comprehensive clinical description of the patient. This contributes to the clinical and neurophysiological characteristic of the sodium channel Nav1.7 channelopathy and expand our genetic knowledge which might provide more accurate and comprehensive clinical electrophysiological and genetic information.

IL-12Rß1 deficiency: mutation update and description of the IL12RB1 variation database.

IL-12Rß1 deficiency is an autosomal recessive disorder characterized by predisposition to recurrent and/or severe infections caused by otherwise poorly pathogenic mycobacteria and salmonella. IL-12Rß1 is a receptor chain of both the IL-12 and the IL-23 receptor and deficiency of IL-12Rß1 thus abolishes both IL-12 and IL-23 signaling. IL-12Rß1 deficiency is caused by bi-allelic mutations in the IL12RB1 gene. Mutations resulting in premature stop codons, such as nonsense, frame shift, and splice site mutations, represent the majority of IL-12Rß1 deficiency causing mutations (66%; 46/70). Also every other morbid mutation completely inactivates the IL-12Rß1 protein. In addition to disease-causing mutations, rare and common variations with unknown functional effect have been reported in IL12RB1. All these variants have been deposited in the online IL12RB1 variation database (www.LOVD.nl/IL12RB1). In this article, we review the function of IL-12Rß1 and molecular genetics of human IL12RB1.

Morbidity characteristics of patients with congenital insensitivity to pain with anhidrosis (CIPA).

BACKGROUND: Congenital insensitivity to pain with anhidrosis (CIPA) is a congenital autonomic sensory neuropathy. In southern Israel, there are many patients with this disease. We here tried to characterize the different infections acquired by children with CIPA. METHODS: We collected all the available data about CIPA patients in southern Israel in the year 1991-2005, including the lesion types, area in the body where the infection occurs, and the treatment given. RESULTS: The current study included 30 children with CIPA, out of 44 known CIPA patients in southern Israel (68.2%). A total of 382 different episodes of infections, fever, orthopedic lesions, and jaw and mouth lesions led our patients to our outpatient clinic or resulted in hospitalization. CONCLUSION: We found that children with CIPA mainly have infections of the skin and skeleton, and that the most frequent pathogen is Staphylococcus aureus. We also found that a fair amount of these pathogens are resistant to conventional treatment regimens.

Variation of muscular structure in congenital insensitivity to pain and anhidrosis.

Congenital insensitivity to pain with anhidrosis is a rare disease affecting the nervous system. The patients present with unexplained fever from poor thermoregulation and inability to sweat. Because of the indifference to pain, they manifest frequent traumatic and infectious injuries. Evaluations of these patients include investigation of the hypotonia and weakness evident in this group of patients. We report four patients presenting characteristic features of congenital insensitivity to pain with anhidrosis who carry an identical mutation in the TRK-A gene and who underwent nerve and skeletal muscle biopsies. All four patients had normal sensory and motor conduction studies but lacked sympathetic skin responses. Examination of the skeletal muscles biopsies obtained from two of the patients disclosed marked myopathic changes. The muscle biopsy of a third patient showed mild variation in muscle fibers and the fourth patient's muscle biopsy showed type 1 fiber predominance. Electron microscopy studies revealed remarkable decrease in the number of small caliber-myelinated and unmyelinated nerve fibers. We assume that the variable histological findings in the muscle biopsies of these patients reflect a variation in congenital insensitivity to pain with anhidrosis patients that is not related to their genetic mutation.

Pathological fracture of the mandible in a paediatric patient with congenital insensitivity to pain with anhidrosis (CIPA).

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare hereditary sensory and autonomic neuropathy (HSAN) characterized by pain, self-mutilating behaviour, anhidrosis and recurrent hyperthermia. CIPA has a multisystem involvement, including fractures of the extremities with slow healing, immunologic abnormalities, and a chronic inflammatory state. The mandible is reported to have a higher incidence of osteomyelitis, though mandibular fracture among CIPA patients, is very rare, with to our knowledge no reports in children. A case of pathological fracture of the mandible in a 6-year-old child with CIPA treated by ORIF is reported. In contrast to the slow healing reported in long bones, the mandible healed very quickly, possibly indicating that the osteoporotic mandible in this group of patients is different from that seen in the elderly. Furthermore, the standard ORIF technique can be safely used in this rare group.

Two X-linked chronic granulomatous disease patients with unusual NADPH oxidase properties.

BACKGROUND: Chronic granulomatous disease (CGD) is an immune deficiency syndrome caused by defects in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, the enzyme that generates reactive oxygen species (ROS) in phagocytizing leukocytes. This study evaluates the NADPH oxidase capacity in two X-linked CGD patients with mutations in gp91(phox) that alter the regions in this membrane-bound NADPH oxidase component involved in docking of the cytosolic component p47(phox). MATERIALS AND METHODS: Hydrogen peroxide and superoxide generation, bactericidal activity, and NADPH oxidase protein expression by the patients' neutrophils were measured, and genetic analysis was performed. RESULTS: We report two patients, each with a novel missense mutation in CYBB, the gene that encodes gp91(phox). Surprisingly, neutrophils from these patients showed total absence of superoxide production, although they retained 13-30% of the hydrogen peroxide production capability. We speculate that this is due to direct electron transfer from flavin adenine dinucleotide (FAD) in gp91(phox) to oxygen, leading to inefficient hydrogen peroxide formation instead of efficient superoxide production. CONCLUSIONS: X-linked CGD patients with mutations that alter the gp91(phox) protein in regions involved in docking of the cytosolic NADPH oxidase component p47(phox) may have higher than expected hydrogen peroxide generation capability.

Osteomyelitis of the mandible in a group of 33 pediatric patients with congenital insensitivity to pain with anhidrosis.

OBJECTIVE: To determine the frequency of mandibular osteomyelitis (OM) in patients with congenital insensitivity to pain with anhidrosis (CIPA) and to relate its appearance to possible risk factors. METHODS: The records of 33 patients were reviewed for data concerning events of jaw OM, oral trauma, maxillofacial interventions, or OM of long bones. RESULTS: Eighteen percent of the patients had mandibular OM. Of the six patients, preceding oral laceration was documented in one and tooth extraction in two. Seventy percent of the patients had OM of the limbs, but only 15% overlapped, having both jaw and limb OM. Half of the patients with mandibular OM had also OM of the limbs during the following year. There seems to be a correlation between high frequency of limb OM (at least 5 events per patient) and appearance of mandibular OM. CONCLUSION: The incidence of mandibular OM is very high among patients with CIPA and can result in pathologic fracture and the need for open reduction and internal fixation. The reason for this phenomenon is presently not clear. Preventive and therapeutic strategy for CIPA patients should be undertaken to minimize this severe complication.

Congenital insensitivity to pain: novel SCN9A missense and in-frame deletion mutations.

SCN9Aencodes the voltage-gated sodium channel Na(v)1.7, a protein highly expressed in pain-sensing neurons. Mutations in SCN9A cause three human pain disorders: bi-allelic loss of function mutations result in Channelopathy-associated Insensitivity to Pain (CIP), whereas activating mutations cause severe episodic pain in Paroxysmal Extreme Pain Disorder (PEPD) and Primary Erythermalgia (PE). To date, all mutations in SCN9A that cause a complete inability to experience pain are protein truncating and presumably lead to no protein being produced. Here, we describe the identification and functional characterization of two novel non-truncating mutations in families with CIP: a homozygously-inherited missense mutation found in a consanguineous Israeli Bedouin family (Na(v)1.7-R896Q) and a five amino acid in-frame deletion found in a sporadic compound heterozygote (Na(v)1.7-DeltaR1370-L1374). Both of these mutations map to the pore region of the Na(v)1.7 sodium channel. Using transient transfection of PC12 cells we found a significant reduction in membrane localization of the mutant protein compared to the wild type. Furthermore, voltage clamp experiments of mutant-transfected HEK293 cells show a complete loss of function of the sodium channel, consistent with the absence of pain phenotype. In summary, this study has identified critical amino acids needed for the normal subcellular localization and function of Na(v)1.7.

Assessment of cognitive and adaptive behaviour among individuals with congenital insensitivity to pain and anhidrosis.

AIM: Individuals with congenital insensitivity to pain with anhidrosis (CIPA) are reported to have mental retardation* but to our knowledge no detailed study on the subject has ever been published. The present study assessed and documented cognitive and adaptive behaviour among Arab Bedouin children with CIPA. METHODS: Twenty-three Arab Bedouin children (12 females, 11 males) with CIPA aged between 3 and 17 years (mean 9 y 7 mo, SD 4 y 2 mo) were assessed. They were compared with 19 healthy siblings of the affected children aged between 5 and 13 years (mean 8 y 11 mo, SD 2 y 10 m). All of the children in the comparison group, but only half of the CIPA group, were attending school. The children were evaluated using a standardized, non-verbal intelligence test, the Leiter International Performance Scale--Revised, and an adaptive behaviour questionnaire, the Vineland Adaptive Behaviour Scales, 2nd edition. RESULTS: Based on scores on the intelligence test and the adaptive behaviour scale, children with CIPA functioned in the mental retardation range (mean IQ scores: CIPA group 53.8, comparison group 83.32 [p<0.001]; adaptive behaviour: CIPA group 68.1, comparison group 104.88 [p<0.001]). IQ was significantly higher among the children with CIPA aged up to 7 years 11 months than among the older children 73.83 vs 45.21 (p<0.001). INTERPRETATION: As a group, the younger children with CIPA may be functioning above the mental retardation range. We propose that early intervention addressing these children's needs and developing an appropriate educational system, might improve their outcome.