Abstract MPDZ , a gene with diverse functions mediating cell–cell junction interactions, receptor signaling, and binding multivalent scaffold proteins, is associated with a spectrum of clinically ...heterogeneous phenotypes with biallelic perturbation. Despite its clinical relevance, the mechanistic underpinnings of these variants remain elusive, underscoring the need for extensive case series and functional investigations. In this study, we conducted a systematic review of cases in the literature through two electronic databases following the PRISMA guidelines. We selected nine studies, including 18 patients, with homozygous or compound heterozygous variants in MPDZ and added five patients from four unrelated families with novel MPDZ variants. To evaluate the role of Mpdz on hearing, we analyzed available auditory electrophysiology data from a knockout murine model ( Mpdz em1(IMPC)J/em1(IMPC)J ) generated by the International Mouse Phenotyping Consortium. Using exome and genome sequencing, we identified three families with compound heterozygous variants, and one family with a homozygous frameshift variant. MPDZ ‐related disease is clinically heterogenous with hydrocephaly, vision impairment, hearing impairment and cardiovascular disease occurring most frequently. Additionally, we describe two unrelated patients with spasticity, expanding the phenotypic spectrum. Our murine analysis of the Mpdz em1(IMPC)J/em1(IMPC)J allele showed severe hearing impairment. Overall, we expand understanding of MPDZ ‐related phenotypes and highlight hearing impairment and spasticity among the heterogeneous phenotypes.
Copy number variation studies of known disorders have the potential to improve the characterization of clinical phenotypes and may help identifying candidate genes and their pathways. The authors ...described a child with congenital heart disease, microcephaly, facial dysmorphisms, developmental delay, learning difficulties, and behavioral problems. There was initially a clinical suspicion of 22q11.2 deletion syndrome (22q11.2 DS), but molecular cytogenetic analysis (array genomic hybridization aGH) showed the presence of a de novo 3.6-Mb interstitial microdeletion in 8p23.1. The main features of 8p23.1 DS include congenital heart disease and behavioral problems, in addition to minor dysmorphisms and mental delay. Therefore, this article highlights the application of aGH to investigate 8p23.1 deletion in nonconfirmed 22q11.2 DS patients presenting neurobehavioral disorders, congenital cardiopathy, and minor dysmorphisms.
The 22q11.2 deletion is the most frequent interstitial deletion in humans and presents a wide phenotypic spectrum, with over 180 clinical manifestations described. Distinct studies have detected ...frequencies of the deletion ranging from 0 % to 75 %, depending on the studied population and selection criteria adopted. Due to the lack of consensus in this matter, several studies have been conducted aiming to define which patients would be eligible for screening; however, the issue is still up for debate. In order to contribute to the delineation of possible clinical and dysmorphologic guidelines to optimize decision making in the clinical setting, 194 individuals with variable features of the 22q11.2 deletion syndromes (22q11.2DS) were evaluated. Group I, clinical suspicion of 22q11.2DS with palatal anomalies; Group II, clinical suspicion without palatal anomalies; Group III, cardiac malformations associated with the 22q11.2DS; and Group IV, juvenile-onset schizophrenia. Multiplex ligation-dependent probe amplification was used for screening the 22q11.2 deletion, which was detected in 45 patients (23.2 %), distributed as such: Group I, 35/101 (34.7 %); Group II, 4/18 (22.2 %); Group III, 6/52 (11.5 %); and Group IV, 0/23 (0 %). Clinical data were analyzed by frequency distribution and statistically. Based on the present results and on the review of the literature, we propose a set of guidelines for screening patients with distinct manifestations of the 22q11.2DS in order to maximize resources. In addition, we report the dysmorphic features which we found to be statistically correlated with the presence of the 22q11.2DS.
Overcoming challenges for the unambiguous detection of copy number variations is essential to broaden our understanding of the role of genomic variants in the clinical phenotype. With the improvement ...of software and databases, whole-exome sequencing quickly can become an excellent strategy in the routine diagnosis of patients with a developmental delay and/or multiple congenital malformations. However, even after a detailed analysis of pathogenic single-nucleotide variants and indels in known disease genes, using whole-exome sequencing, some patients with suspected syndromic conditions are left without a conclusive diagnosis. These negative results could be the result of different factors including nongenetic etiologies, lack of knowledge about the genes that cause different disease phenotypes, or, in some cases, a deletion or duplication of genomic information not routinely detectable by whole-exome sequencing variant calling. Although copy number variant detection is possible using whole-exome sequencing data, such analysis presents significant challenges and cannot yet be used to replace chromosomal arrays for identification of deletions or duplications.
Erythrina velutina
is a species of arboreal leguminous that occurs spontaneously in the northeastern states of Brazil. Leguminous seeds represent an abundant source of peptidase inhibitors, which ...play an important role in controlling peptidases involved in essential biological processes. The aim of this study was to purify and characterize a novel Kunitz-type peptidase inhibitor from
Erythrina velutina
seeds and evaluate its anti-proliferative effects against cancer cell lines. The Kunitz-type chymotrypsin inhibitor was purified from
Erythrina velutina
seeds (EvCI) by ammonium sulphate fractionation, trypsin– and chymotrypsin–sepharose affinity chromatographies and Resource Q anion-exchange column. The purified EvCI has a molecular mass of 18 kDa with homology to a Kunitz-type inhibitor. Inhibition assays revealed that EvCI is a competitive inhibitor of chymotrypsin (with
K
i
of 4 × 10
–8
M), with weak inhibitory activity against human elastase and without inhibition against trypsin, elastase, bromelain or papain. In addition, the inhibitory activity of EvCI was stable over a wide range of pH and temperature. Disulfide bridges are involved in stabilization of the reactive site in EvCI, since the reduction of disulfide bridges with DTT 100 mM abolished ~ 50% of its inhibitory activity. The inhibitor exhibited selective anti-proliferative properties against HeLa cells. The incubation of EvCI with HeLa cells triggered arrest in the cell cycle, suggesting that apoptosis is the mechanism of death induced by the inhibitor. EvCI constitutes an interesting anti-carcinogenic candidate for conventional cervical cancer treatments employed currently. The EvCI cytostatic effect on Hela cells indicates a promised compound to be used as anti-carcinogenic complement for conventional cervical treatments employed currently.
Objectives
The aim of this study was to describe clinical features in subjects with palatal abnormalities and to assess the distribution of these features among those with and without 22q11.2 ...deletion.
Design
Descriptive cohort.
Patients
One hundred patients with palatal abnormalities and suspicion of 22q11.2 DS were included.
Methods
All patients were evaluated by a clinical geneticist, who completed a standardized clinical protocol. The 22q11.2 deletion screening was performed with fluorescence in situ hybridization using the TUPLE1 probe and multiplex ligation-dependent probe amplification using the P250-A1 kit.
Results
The 22q11.2 deletion was detected in 35 patients, in whom the most frequent clinical features were congenital heart disease (15/30 – 50%), developmental delay (19/35 – 54%), speech delay (20/35 – 57%), learning disabilities (27/35 – 77%), immunologic alterations (18/29 – 62%). In addition, the most common facial dysmorphisms in this group were long face (27/35 – 77%), typical nose (24/35 – 69%), and hooded eyelids (19/35 – 54%). Comparing features in patients with or without the deletion revealed significant differences (positively correlated with the deletion) for speech delay, learning disabilities, conductive hearing loss, number of dysmorphisms, long face, and hooded eyelids. Cleft lip and palate was negatively correlated with the deletion.
Conclusions
The presence of speech delay, learning disabilities, conductive hearing loss, long face, and hooded eyelids should reinforce the suspicion of 22q11.2 DS in patients with palatal abnormalities and would help professionals direct clinical follow-up of these patients.
In the last few decades, different methods for the detection of genomic imbalances, such as the microdeletion syndromes, were developed. The 22q11.2 deletion syndrome (22q11.2DS) is the most common ...microdeletion syndrome and presents wide clinical heterogeneity. The aim of this study was to describe 4 unusual cases of genomic imbalances found in individuals with suspected microdeletion syndromes. Different methods were necessary to complete the diagnosis and to obtain information for genetic counseling. The study was retrospective and descriptive. From August 2014 to December 2015, 39 individuals were assessed using FISH and/or MLPA; in 15 cases, chromosomal microarray (CMA) analysis was carried out. Of 39 registered individuals, we found deletions in the 22q11.2 region in 10 individuals (8 individuals with 22q11.2DS and 2 individuals presenting with atypical deletions in the 22q11.2 region: 1 distal deletion and 1 central deletion). In one case with a typical 22q11.2 deletion, a familial balanced translocation was detected. In another case without a 22q11.2 deletion, a 6p duplication concomitant with a 9p deletion was detected by CMA. Clinical data are reported and diagnostic investigations are discussed. Essential aspects for the understanding of different diagnostic techniques of genomic imbalances are considered, and the 4 cases described underline the complexity and the difficulties involved in the diagnostic process. The approach is informative for clinical practice and may be applied in other contexts of genomic imbalance investigation in microdeletion syndromes.
Abstract
Velocardiofacial syndrome is one of the recognized forms of chromosome 22q11.2 deletion syndrome (22q11.2 DS) and has an incidence of 1 of 4,000 to 1 of 6,000 births. Nevertheless, the 22q11 ...deletion is not found in several patients with a 22q11.2 DS phenotype. In this situation, other chromosomal aberrations and/or mutations in the T-box 1 transcription factor C (
TBX1
) gene have been detected in some patients. A similar phenotype to that of the 22q11.2 DS has been reported in animal models with mutations in fibroblast growth factor 8 (
Fgf8
) gene. To date,
FGF8
mutations have not been investigated in humans. We tested a strategy to perform laboratory testing to reduce costs in the investigation of patients presenting with the 22q11.2 DS phenotype. A total of 109 individuals with clinical suspicion were investigated using GTG-banding karyotype, fluorescence in situ hybridization, and/or multiplex ligation-dependent probe amplification. A conclusive diagnosis was achieved in 33 of 109 (30.2%) cases. In addition, mutations in the coding regions of
TBX1
and
FGF8
genes were investigated in selected cases where 22q11.2 deletion had been excluded, and no pathogenic mutations were detected in both genes. This study presents a strategy for molecular genetic characterization of patients presenting with the 22q11.2 DS using different laboratory techniques. This strategy could be useful in different countries, according to local resources. Also, to our knowledge, this is the first investigation of
FGF8
gene in humans with this clinical suspicion.
Objective: To report a series of atypical presentations of Aicardi–Goutières syndrome. Methods: Clinical, neuroimaging, and genetic data. Results: We report a series of six unrelated patients (five ...males) with a subacute loss of developmental milestones, pyramidal signs, and regression of communication abilities, with onset at ages ranging from 7 to 20 months, reaching a nadir after 4 to 24 weeks. A remarkable improvement of lost abilities occurred in the follow-up, and they remained with residual spasticity and dysarthria but preserved cognitive function. Immunization or febrile illness occurred before disease onset in all patients. CSF was normal in two patients, and in four, borderline or mild lymphocytosis was present. A brain CT scan disclosed a subtle basal ganglia calcification in one of six patients. Brain MRI showed asymmetric signal abnormalities of white matter with centrum semi-ovale involvement in five patients and a diffuse white matter abnormality with contrast enhancement in one. Four patients were diagnosed and treated for acute demyelinating encephalomyelitis (ADEM). Brain imaging was markedly improved with one year or more of follow-up (average of 7 years), but patients remained with residual spasticity and dysarthria without cognitive impairment. Demyelination relapse occurred in a single patient four years after the first event. Whole-exome sequencing (WES) was performed in all patients: four of them disclosed biallelic pathogenic variants in RNASEH2B (three homozygous p.Ala177Thr and one compound heterozygous p.Ala177Thr/p.Gln58*) and in two of them the same homozygous deleterious variants in RNASEH2A (p.Ala249Val). Conclusions: This report expands the phenotype of AGS to include subacute developmental regression with partial clinical and neuroimaging improvement. Those clinical features might be misdiagnosed as ADEM.
The Na+/K+- ATPase acts as an ion pump maintaining the essential plasma membrane potential in all mammalian cell types, and is essential for many cellular functions. There are four α isoforms (α1, ...α2, α3 and α4) with distinct expression patterns, kinetic properties and substrate affinity. The α2-isoform is encoded by ATP1A2 and evidence supports its utmost importance in Cl− homeostasis in neurons, and in the function of respiratory neurons at birth. Monallelic pathogenic variants in ATP1A2 are associated with familial hemiplegic migraine type 2 (FHM2) and on rare occasions with alternating hemiplegia of childhood 1 (AHC1). To date, no instances of biallelic loss of function variants have been reported in humans. However, Atp1a2 homozygous loss of function knockout mice (α2−/− mice) show severe motor deficits, with lack of spontaneous movements, and are perinatally lethal due to absent respiratory activity. In this report we describe three newborns from two unrelated families, who died neonatally, presenting in utero with an unusual form of fetal hydrops, seizures and polyhydramnios. At birth they had multiple joint contractures (e.g. arthrogryposis), microcephaly, malformations of cortical development, dysmorphic features and severe respiratory insufficiency. Biallelic loss of function variants in ATP1A2, predicted to be pathogenic were found on whole exome sequencing. We propose that this is a distinctive new syndrome caused by complete absence of Na+/K+- ATPase α2-isoform expression.
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