Aagenaes syndrome/lymphedema cholestasis syndrome 1 is caused by a founder variant in the 5'-untranslated region of UNC45A.

BACKGROUND & AIMS: Lymphedema cholestasis syndrome 1 or Aagenaes syndrome is a condition characterized by neonatal cholestasis, lymphedema, and giant cell hepatitis. The genetic background of this autosomal recessive disease was unknown up to now. METHODS: A total of 26 patients with Aagenaes syndrome and 17 parents were investigated with whole-genome sequencing and/or Sanger sequencing. PCR and western blot analyses were used to assess levels of mRNA and protein, respectively. CRISPR/Cas9 was used to generate the variant in HEK293T cells. Light microscopy, transmission electron microscopy and immunohistochemistry for biliary transport proteins were performed in liver biopsies. RESULTS: One specific variant (c.-98G>T) in the 5'-untranslated region of Unc-45 myosin chaperone A (UNC45A) was identified in all tested patients with Aagenaes syndrome. Nineteen were homozygous for the c.-98G>T variant and seven were compound heterozygous for the variant in the 5'-untranslated region and an exonic loss-of-function variant in UNC45A. Patients with Aagenaes syndrome exhibited lower expression of UNC45A mRNA and protein than controls, and this was reproduced in a CRISPR/Cas9-created cell model. Liver biopsies from the neonatal period demonstrated cholestasis, paucity of bile ducts and pronounced formation of multinucleated giant cells. Immunohistochemistry revealed mislocalization of the hepatobiliary transport proteins BSEP (bile salt export pump) and MRP2 (multidrug resistance-associated protein 2). CONCLUSIONS: c.-98G>T in the 5'-untranslated region of UNC45A is the causative genetic variant in Aagenaes syndrome. IMPACT AND IMPLICATIONS: The genetic background of Aagenaes syndrome, a disease presenting with cholestasis and lymphedema in childhood, was unknown until now. A variant in the 5'-untranslated region of the Unc-45 myosin chaperone A (UNC45A) was identified in all tested patients with Aagenaes syndrome, providing evidence of the genetic background of the disease. Identification of the genetic background provides a tool for diagnosis of patients with Aagenaes syndrome before lymphedema is evident.

APOE-ε4 Is Associated With Reduced Verbal Memory Performance and Higher Emotional, Cognitive, and Everyday Executive Function Symptoms Two Months After Mild Traumatic Brain Injury.

BACKGROUND: Substantial variance exists in outcomes after mild traumatic brain injury (MTBI), and these differences are not fully explained by injury characteristics or severity. Genetic factors are likely to play a role in this variance. OBJECTIVES: The aim of this study was to examine associations between the apolipoprotein (APOE)-ε4 allele and memory measures at two months post-MTBI and to evaluate whether subjective cognitive and affective symptoms were associated with APOE-ε4 status. Based on previous research, it was hypothesized that APOE-ε4 carriers would show poorer verbal memory performance compared to APOE-ε4 non-carriers. METHODS: Neuropsychological data at two months post-injury and blood samples that could be used to assess APOE genotype were available for 134 patients with MTBI (mean age 39.2 years, 62% males, 37% APOE-ε4 carriers). All patients underwent computed tomography at hospital admission and magnetic resonance imaging four weeks post-injury. RESULTS: The APOE-ε4 + status was associated with decreased immediate memory recall (p = 0.036; ß = -0.10, 95% CI [-0.19, -0.01]). Emotional, cognitive, and everyday executive function symptoms at two months post-injury were significantly higher in APOE-ε4 carriers compared to non-carriers. CONCLUSION: The APOE-ε4+ allele has a negative effect on verbal memory and symptom burden two months after MTBI.

Apolipoprotein ɛ4 Status and Brain Structure 12 Months after Mild Traumatic Injury: Brain Age Prediction Using Brain Morphometry and Diffusion Tensor Imaging.

BACKGROUND: Apolipoprotein E (APOE) ɛ4 is associated with poor outcome following moderate to severe traumatic brain injury (TBI). There is a lack of studies investigating the influence of APOE ɛ4 on intracranial pathology following mild traumatic brain injury (MTBI). This study explores the association between APOE ɛ4 and MRI measures of brain age prediction, brain morphometry, and diffusion tensor imaging (DTI). METHODS: Patients aged 16 to 65 with acute MTBI admitted to the trauma center were included. Multimodal MRI was performed 12 months after injury and associated with APOE ɛ4 status. Corrections for multiple comparisons were done using false discovery rate (FDR). RESULTS: Of included patients, 123 patients had available APOE, volumetric, and DTI data of sufficient quality. There were no differences between APOE ɛ4 carriers (39%) and non-carriers in demographic and clinical data. Age prediction revealed high accuracy both for the DTI-based and the brain morphometry based model. Group comparisons revealed no significant differences in brain-age gap between ɛ4 carriers and non-carriers, and no significant differences in conventional measures of brain morphometry and volumes. Compared to non-carriers, APOE ɛ4 carriers showed lower fractional anisotropy (FA) in the hippocampal part of the cingulum bundle, which did not remain significant after FDR adjustment. CONCLUSION: APOE ɛ4 carriers might be vulnerable to reduced neuronal integrity in the cingulum. Larger cohort studies are warranted to replicate this finding.

Whole exome sequencing of sporadic patients with Currarino Syndrome: A report of three trios.

Currarino Syndrome is a rare congenital malformation syndrome described as a triad of anorectal, sacral and presacral anomalies. Currarino Syndrome is reported to be both familial and sporadic. Familial CS is today known as an autosomal dominant disorder caused by mutations in the transcription factor MNX1. The aim of this study was to look for genetic causes of Currarino Syndrome in sporadic patients after ruling out other causes, like chromosome aberrations, disease-causing variants in possible MNX1 cooperating transcription factors and aberrant methylation in the promoter of the MNX1 gene. The hypothesis was that MNX1 was affected through interactions with other transcription factors or through other regulatory elements and thereby possibly leading to abnormal function of the gene. We performed whole exome sequencing with an additional 6Mb custom made region on chromosome 7 (GRCh37/hg19, chr7:153.138.664-159.138.663) to detect regulatory elements in non-coding regions around the MNX1 gene. We did not find any variants in genes of interest shared between the patients. However, after analyzing the whole exome sequencing data with Filtus, the in-house SNV filtration program, we did find some interesting variants in possibly relevant genes that could be explaining these patients` phenotypes. The most promising genes were ETV3L, ARID5A and NCAPD3. To our knowledge this is the first report of whole exome sequencing in sporadic CS patients.

Familial globotriaosylceramide-associated cardiomyopathy mimicking Fabry disease.

OBJECTIVE: To characterise a globotriaosylceramide (Gb3) storage cardiomyopathy mimicking Fabry. METHODS: We investigated five patients from two unrelated families with early adult onset unexplained left ventricular hypertrophy. Endomyocardial biopsy was performed in all patients and diagnostic kidney biopsies in two of them. We measured α-galactosidase A activity in all patients. Three patients were checked for LAMP1 or LAMP2 deficiency and screened for congenital disorders of glycosylation. Gb3 concentration was quantified in plasma, urinary sediment and cardiac muscle. We sequenced the Fabry and Danon genes and looked for other genetic causes by single-nucleotide polymorphism array haplotyping and whole exome sequencing. RESULTS: Three patients had a striking fat distribution around the buttocks and upper thighs. All patients developed bradyarrhythmias and needed pacemakers. Cardiac transplantation was performed in three patients due to end-stage heart failure, one patient died before transplantation. The cardiomyocytes contained lysosomal vacuoles with lamellar myelin-like deposits. Interstitial cells had vacuoles containing granular material. Deposits were found in the kidneys without renal dysfunction. The histological pattern was atypical for Fabry disease. Biochemical studies revealed normal activity of α-galactosidase A and other relevant enzymes. There was a selective accumulation of Gb3 in cardiomyocytes, at levels found in patients with Fabry disease, but no mutations in the Fabry gene, and Fabry disease was excluded. Other known lysosomal storage diseases were also excluded. Single-nucleotide polymorphism array haplotyping and whole exome sequencing could not identify the genetic cause. CONCLUSIONS: We describe a novel familial Gb3-associated cardiomyopathy. Autosomal recessive inheritance is likely, but the genetic and metabolic cause remains to be identified.

CCBE1 mutation in two siblings, one manifesting lymphedema-cholestasis syndrome, and the other, fetal hydrops.

BACKGROUND: Lymphedema-cholestasis syndrome (LCS; Aagenaes syndrome) is a rare autosomal recessive disorder, characterized by 1) neonatal intrahepatic cholestasis, often lessening and becoming intermittent with age, and 2) severe chronic lymphedema, mainly lower limb. LCS was originally described in a Norwegian kindred in which a locus, LCS1, was mapped to a 6.6cM region on chromosome 15. Mutations in CCBE1 on chromosome 18 have been reported in some cases of lymphatic dysplasia, but not in LCS. METHODS: Consanguineous parents of Mexican ancestry had a child with LCS who did not exhibit extended homozygosity in the LCS1 region. A subsequent pregnancy was electively terminated due to fetal hydrops. We performed whole-genome single nucleotide polymorphism genotyping to identify regions of homozygosity in these siblings, and sequenced promising candidate genes. RESULTS: Both siblings harbored a homozygous mutation in CCBE1, c.398 T>C, predicted to result in the missense change p.L133P. Regions containing known 'cholestasis genes' did not demonstrate homozygosity in the LCS patient. CONCLUSIONS: Mutations in CCBE1 may yield a phenotype not only of lymphatic dysplasia, but also of LCS or fetal hydrops; however, the possibility that the sibling with LCS also carries a homozygous mutation in an unidentified gene influencing cholestasis cannot be excluded.

A 5.8 kb deletion removing the entire MNX1 gene in a Norwegian family with Currarino syndrome.

Currarino syndrome (CS) is a clinically variable disorder characterized by anorectal, sacral and presacral anomalies. It is associated with loss-of-function mutations in the motor neuron and pancreas homeobox 1 (MNX1) gene. Inheritance is autosomal dominant, expression variable and penetrance incomplete. We describe a Norwegian family with typical CS in which a heterozygous deletion removes the entire MNX1 gene but no other known genes. We also report MNX1 mutations in three other Norwegian families and confirm that the GCC12 repeat (c.373_375[12]) is a normal allelic variant. This work underscores the importance of dosage analysis of MNX1 when Sanger sequencing is negative.

Characterization of a Norwegian cherubism cohort; molecular genetic findings, oral manifestations and quality of life.

Bilateral multilocular radiolucencies of the mandible are the main feature of cherubism (OMIM #118400), a rare autosomal dominant disorder primarily affecting the jaw. Typically, symmetrical swelling of the lower face is evident from around three years of age and increases until puberty. The underlying radiolucent lesions consist of vascular fibrotic stroma with scattered multinuclear giant cells. By age 30 years the facial contours are often unremarkable. Missing and displaced teeth as well as premature tooth loss are characteristic. Diagnosis rests upon a combination of clinical, radiographic, histological and molecular findings. SH3BP2 is currently the only gene known to be associated with cherubism. This cross-sectional study describes oral manifestations, quality of life and results of mutation analysis of SH3BP2 in 11 females and 13 males ages five to 84 years with cherubism. One individual with molecularly confirmed Noonan syndrome was excluded from the cohort. Standard statistical tools were used to analyze quality of life data. Mutation analysis was positive in all 22 familial and negative in both sporadic cases. Disease manifestations in mutation carriers varied from none to severe. Although intra-familial variability was marked, we found no evidence of non-penetrance, and females were on average more severely affected than males. Dental sequelae were pronounced; adults lacked a mean of 13 teeth (range 2-28), 13 of 17 individuals aged 16 years and older had removable or fixed dentures and five had dental implants; implant survival rate was 79%. In spite of pronounced disease manifestations and dental sequelae, adult quality of life was good.

Copy number variation findings among 50 children and adolescents with autism spectrum disorder.

OBJECTIVES: Autism spectrum disorders (ASDs) are a heterogeneous group of neurodevelopment disorders with a complex genetic aetiology. The aim of this study was to identify copy number variations (CNVs) with a clinical significance for ASD. MATERIALS AND METHODS: Array-based comparative genomic hybridization was applied to detect CNVs in a clinically well-characterized population of 50 children and adolescents with ASD. RESULTS: Nine CNVs with predicted clinical significance were identified among eight individuals (detection rate 16%). Three of the CNVs are recurrently associated with ASDs (15q11.2q13.1) or have been identified in ASD populations [3p14.2 and t(8;12)(p23.1;p13.31)]. The remaining regions (15q11.2, 10q21.1, Xp22.2, 16p13.3 and 22q13.1) have not been reported previously as candidate genes for ASD. CONCLUSION: This study identified five novel CNVs among the individuals. The causal relationship between identified CNVs and the ASD phenotype is not fully established. However, the genes involved are associated with ASD and/or other neuropsychiatric disorders, or implicated in synaptic and neuronal activity, thus suggesting clinical significance. Further identification of ASD-associated CNVs is required, together with a broad clinical characterization of affected individuals to identify genotype-phenotype correlations.

Two new Rett syndrome families and review of the literature: expanding the knowledge of MECP2 frameshift mutations.

BACKGROUND: Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder, which is usually caused by de novo mutations in the MECP2 gene. More than 70% of the disease causing MECP2 mutations are eight recurrent C to T transitions, which almost exclusively arise on the paternally derived X chromosome. About 10% of the RTT cases have a C-terminal frameshift deletion in MECP2. Only few RTT families with a segregating MECP2 mutation, which affects female carriers with a phenotype of mental retardation or RTT, have been reported in the literature. In this study we describe two new RTT families with three and four individuals, respectively, and review the literature comparing the type of mutations and phenotypes observed in RTT families with those observed in sporadic cases. Based on these observations we also investigated origin of mutation segregation to further improve genetic counselling. METHODS: MECP2 mutations were identified by direct sequencing. XCI studies were performed using the X-linked androgen receptor (AR) locus. The parental origin of de novo MECP2 frameshift mutations was investigated using intronic SNPs. RESULTS: In both families a C-terminal frameshift mutation segregates. Clinical features of the mutation carriers vary from classical RTT to mild mental retardation. XCI profiles of the female carriers correlate to their respective geno-/phenotypes. The majority of the de novo frameshift mutations occur on the paternally derived X chromosome (7/9 cases), without a paternal age effect. CONCLUSIONS: The present study suggests a correlation between the intrafamilial phenotypic differences observed in RTT families and their respective XCI pattern in blood, in contrast to sporadic RTT cases where a similar correlation has not been demonstrated. Furthermore, we found de novo MECP2 frameshift mutations frequently to be of paternal origin, although not with the same high paternal occurrence as in sporadic cases with C to T transitions. This suggests further investigations of more families. This study emphasizes the need for thorough genetic counselling of families with a newly diagnosed RTT patient.

A novel BMPR2 gene mutation associated with exercise-induced pulmonary hypertension in septal defects.

OBJECTIVE: Our study aimed to investigate the relationship between exercise-induced pulmonary arterial hypertension and genetic changes related to the transforming growth factor-ß (TGF-ß) signalling pathway in patients with cardiac septal defects. DESIGN: In a population-based group of 44 patients (age 13-25 years) with either isolated ventricular septal defect (n=27) or isolated atrial septal defect (n=17), right ventricular systolic pressure response to submaximal exercise was studied by echocardiography and classified as normal (≤45 mmHg), borderline (45-50 mmHg) or abnormal (>50 mmHg). Three genes related to TGF-ß, bone morphogenetic protein receptor type 2 (BMPR2), activin receptor-like kinase 1 (ALK1) and endoglin (ENG), were analyzed by DNA sequencing (only BMPR2) and multiplex ligand-dependent probe amplification (BMPR2, ALK1 and ENG). RESULTS: Pressure response was borderline in five and abnormal in nine patients. Five patients showed mutations in exon 12 of the bone morphogenetic protein receptor type 2 gene. The previously described polymorphism S775N (c. 2324, G > A) was found in three patients with normal pressure response. The mutation Y589C (c. 1766, A > G), which has not been described previously, was found in two of 14 patients with borderline/abnormal pressure response. CONCLUSION: Genetic changes in the BMPR2 gene may be overrepresented in patients with cardiac septal defects and exercise-induced pulmonary hypertension.

Age-dependent clinical problems in a Norwegian national survey of patients with the 22q11.2 deletion syndrome.

Patients with the 22q11.2 deletion syndrome display a wide phenotypic variation that is important for clinical follow-up. In this national survey of 60 patients (ages 1 to 54 years) diagnosed by Fluorescence in situ hybridization test, data were collected from medical records, a physical examination, and a semistructured interview. Ultrasound investigation of the kidneys was also performed. In addition, multiplex ligation probe amplification assay was performed to detect deletion size. Phenotypic features leading to the genetic diagnosis were noted. The patients showed a variety of organ malformations including 39 with heart anomalies. Only 20 individuals had been diagnosed with 22q11.2 DS in the first year of life. Four patients had renal and five males had genital malformations. The increased infection susceptibility (excluding otitis media) and most feeding difficulties subsided during early childhood. Speech difficulties started early and were a major problem for many patients at least until 10 years of age. Ten patients developed kyphoscoliosis in late childhood. In teenagers and adults, abnormal social behavior, learning disabilities, and psychiatric symptoms dominated. Our study which also includes adult patients emphasizes a marked change in challenges in individuals with the 22q11.2 deletion syndrome with increasing age.

Cognitive impairment and the role of the ApoE epsilon4-allele after stroke--a 13 months follow-up study.

OBJECTIVE: To examine the relationship between the ApoE epsilon4 allele and cognitive impairment 13 months after stroke. METHODS: One hundred four stroke rehabilitation patients were cognitively tested on average 18 days after hospital admission and again 13 months later with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The following potential risk factors for post-stroke cognitive impairment (defined by a RBANS total index score below 77.5 points) at 13 months follow-up were analyzed in bivariate and logistic regression analyses: ApoE-genotype, socio-demographic variables, pre-stroke cognitive reduction (The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)), vascular factors, lesion characteristics, and neurological impairment (The National Institute of Health Stroke Scale (NIHSS)). Differences in general cognitive performance (pre-stroke, baseline, and follow-up) across patients with different ApoE-genotypes were analyzed, and lastly differences between epsilon4-carriers and non-carriers for changes in performance in various cognitive domains over the 13 months period were examined. RESULTS: Significant risk factors for cognitive impairment at 13 months were ApoE epsilon4, pre-stroke cognitive reduction (IQCODE 3.44+), previous stroke, and neurological impairment (NIHSS Total Score >5). A significant dose-dependent effect of the ApoE-genotype in relation to overall post-stroke cognitive functioning was found at baseline and follow-up, but not pre-stroke. The epsilon4 carriers showed a significant decline in tests related to verbal learning and memory compared to the non-carriers. CONCLUSIONS: The ApoE epsilon4-allele constitutes an independent risk factor for cognitive impairment at 13 months post-stroke, and is associated with progression of cognitive decline in tasks related to verbal learning and memory.

Association between ApoE epsilon4 and cognitive impairment after stroke.

BACKGROUND AND PURPOSE: The understanding of the contribution of genetic factors to cognitive impairment after stroke is incomplete. The aim of the study was to examine whether the apolipoprotein E epsilon4 allele (ApoE epsilon4) is a risk factor for cognitive impairment in the early phase after stroke. METHODS: The sample comprised 152 Norwegian stroke rehabilitation inpatients (mean age 76.8 years, SD 10.5) examined at a mean of 18.3 days (SD 13.4) after hospital admission. Post-stroke cognitive impairment was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The following proposed risk factors were analysed: ApoE genotype, demographics (age, sex, education), pre-stroke cognitive reduction [Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)], pre-stroke vascular factors (including previous stroke), stroke characteristics (type, location), and neurological stroke-related impairment [National Institutes of Health Stroke Scale (NIHSS)]. Cognitive impairment was defined as an RBANS total index score < or =1.5 SD below the mean. Multiple logistic regression analyses were performed to find risk factors for post-stroke cognitive impairment. RESULTS: Four variables were found to be independent risk factors for cognitive impairment after stroke: ApoE epsilon4 (OR = 3.7; 95% CI = 1.2-11.6), IQCODE score > or =3.44 (OR = 9.2; 95% = CI 2.3-37.2), total or partial anterior stroke syndromes (OR = 3.2; 95% CI = 1.3-8.0), and NIHSS total score >5 (OR = 7.3; 95% CI = 2.7-19.7). No association between ApoE epsilon4 and pre-stroke cognitive reduction (IQCODE) was found. CONCLUSIONS: The presence of one or two ApoE epsilon4 alleles may be a significant independent risk factor for cognitive impairment in the early phase after stroke.

ABCB4 sequence variations in young adults with cholesterol gallstone disease.

BACKGROUND AND AIMS: Mutations in the gene encoding the ABCB4 [adenosine triphosphate (ATP)-binding cassette, sub-family B (MDR/TAP), member 4] transporter lower phosphatidylcholine output into bile and contribute to cholesterol gallstone formation by decreasing the solubility of cholesterol in bile. Mutations in ABCB4 have been identified in patients with low phospholipid-associated cholelithiasis. The aim of the present study was to determine the types and frequencies of ABCB4 mutations in cholecystectomized patients aged <40 years. PATIENTS AND METHODS: Hundred and four patients (mean age 30.6 years, range 12-39) were included in the study and the ABCB4 gene was sequenced. The frequency of missense mutations found in the patient material was measured in 95 healthy controls. The potential functional implications of the ABCB4 missense variations were assessed by computerized analysis (BLOSUM62 and Grantham substitution matrices, polymorphism phenotyping and sorting intolerant from tolerant). RESULTS: One patient was heterozygous for a frameshift mutation (c.1399_1400ins10/p.Y467F fsX25). Another patient was heterozygous for a nonsense mutation (c.3136C>T/p.R1046X). These two mutations are considered detrimental to ABCB4 protein function. In addition, six missense mutations were found in the ABCB4 gene, and three of these were only present in patients. CONCLUSION: In our study, <2% of young gallstone patients were found to be heterozygous for detrimental ABCB4 mutations. The functional implication of several missense mutations remains to be clarified. Thus, mutations in the ABCB4 gene are a rare cause of gallstone disease.

SLC9A6 mutations cause X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome.

Linkage analysis and DNA sequencing in a family exhibiting an X-linked mental retardation (XLMR) syndrome, characterized by microcephaly, epilepsy, ataxia, and absent speech and resembling Angelman syndrome, identified a deletion in the SLC9A6 gene encoding the Na(+)/H(+) exchanger NHE6. Subsequently, other mutations were found in a male with mental retardation (MR) who had been investigated for Angelman syndrome and in two XLMR families with epilepsy and ataxia, including the family designated as having Christianson syndrome. Therefore, mutations in SLC9A6 cause X-linked mental retardation. Additionally, males with findings suggestive of unexplained Angelman syndrome should be considered as potential candidates for SLC9A6 mutations.

CFTR gene mutations and asthma in the Norwegian Environment and Childhood Asthma study.

BACKGROUND: Several candidate genes have been implicated in the etiology of asthma, including the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). Mutations in the CFTR gene result in derangements of mucociliary clearance. Homozygotes for CFTR mutations develop cystic fibrosis (CF), a disorder characterized mainly by lung and pancreas disease. OBJECTIVE: To investigate whether there was an increased frequency of CFTR mutations in asthma patients. METHODS: Seven hundred and three subjects aged 10-11 years from the environment and childhood asthma (ECA) study were included in the present study. Possible associations between asthma, reduced lung function, bronchial hyperresponsiveness (BHR), and increased or decreased nitrogen oxide (NO) levels (based on structural parental interview, spirometry, PD20 methacholine challenge test and exhaled NO measurements), and the five most common CFTR mutations in Norway (DeltaF508, R117H, R117C, 4005+2T-->C, 394delTT), the modulating polymorphisms IVS8(TG)mTn and the IVS8-5T were investigated. RESULTS: No association were found between asthma, reduced lung function, BHR or exhaled NO levels and CF heterozygosity. However, the IVS8(TG)11T7 haplotype was associated with normal lung function. CONCLUSIONS: Our results do not support the hypothesis that CFTR mutations or polymorphisms play a role in the pathogenesis of asthma in children. However, the distribution of Tn(TG)m haplotypes differed between individuals with reduced lung function and individuals with normal lung function.

Novel splicing mutation in the NEMO (IKK-gamma) gene with severe immunodeficiency and heterogeneity of X-chromosome inactivation.

We report on a family with three stillborn males, three affected males who were small for gestational age and died within 8 months, and one male who died at age 5 years. This boy had cone-shaped teeth and oligoodontia. He had serious bacterial infections and inflammatory bowel disease. Mutations in the NF-kappaB essential modulator (NEMO) gene have recently been shown to be the cause of a group of ectodermal dysplasia and immunodeficiency disorders (EDA-ID). Analysis of the NEMO gene revealed a nucleotide change in the consensus sequence of the splicing donor site of exon 6 IVS6 + 5G --> A(1027 + 5G --> A), which has not previously been described in EDA-ID. RT-PCR analysis of fibroblast RNA from an aborted affected male fetus demonstrated a skipping of exons 4, 5, and 6 which resulted in a truncated protein of about 35 kDa revealed by NEMO antibody. The skipping of exons 4, 5, and 6 did not affect the ORF of the C-terminal of NEMO encoded by exons 7, 8, 9, and 10, which contains a coiled-coil motif (CC2), a leucin-zipper (LZ), and a zinc finger motif (ZF) sub-domains of NEMO. IkappaBalpha degradation was strongly impaired in the fetal fibroblasts, suggesting an impaired NF-kappaB signaling. One healthy carrier had a completely skewed X-inactivation pattern with the normal X active, whereas the two other carriers had a random X-inactivation pattern. This family may represent a new phenotype within the EDA-ID disorders. From the heterogeneity in X-inactivation phenotype, we conclude that this mutation is not deleterious enough to be lethal for peripheral blood cells.