Importance of TREC and KREC as molecular markers for immunological evaluation of down syndrome children.

Recurrent and severe infections occurred in children with Down Syndrome (DS) due to immunological parameter defects have been reported. The aim of the study is to evaluate the importance of using T-cell receptor excision circle (TREC) and kappa-deleting recombination excision circle (KREC) as molecular markers for immunological investigation of children with DS. The study included 40 non-disjunction trisomy 21 confirmed DS children, and 25 healthy controls. Peripheral blood (PB) was analyzed for lymphocyte subpopulations by flow cytometry, serum immunoglobulin levels, and TREC and KREC copy numbers using quantitative real-time PCR. DS patients showed significantly lower absolute counts of PB T lymphocytes, T helper lymphocytes, T cytotoxic lymphocytes, B lymphocytes, and Natural killer cells, and lower serum IgA, IgG, and IgM levels compared to healthy controls. Copy number of TREC and KREC showed no significant differences between DS patients and healthy controls. There is a significant positive correlation between TREC copy number with a percentage and absolute count of helper T lymphocytes in patients. Also, the KREC copy number was significantly negatively correlated with the age of patients. These findings suggest that copy numbers of TREC and KREC could be useful as molecular markers for immunological evaluation of patients with DS.

Expanding the phenotypic spectrum and clinical severity associated with WLS gene.

WLS (Wnt ligand secretion mediator or Wntless) orchestrates the secretion of all Wnt proteins, a family of evolutionary conserved proteins, involved in Wnt signaling pathway that has many essential biological functions including the regulation of development, cell proliferation, migration and apoptosis. Biallelic variants in WLS have recently been described in 10 patients with pleiotropic multiple congenital anomalies (MCA) known as Zaki syndrome. We identified a likely disease-causing variant in WLS (c.1579G>A, p.Gly527Arg) in a boy presented with a broad range of MCA including microcephaly, facial dysmorphism, alopecia, ophthalmologic anomalies, and complete soft tissue syndactyly. These features were reminiscent of Zaki syndrome although variable clinical severity was observed. In a detailed clinical assessment, our patient also displayed microphthalmia, dental anomalies, skeletal dysplasia with spontaneous fractures and Dandy-Walker malformation. As such, we extend the phenotype linked to Zaki syndrome. This study further highlights the importance of a thorough clinical evaluation to delineate the phenotypic spectrum associated with WLS variants and suggests that genotype-phenotype correlations due to variant localization seems likely. However, future work on additional patients and more functional studies may give further insights into genotype-phenotype correlations and the complex function of WLS.

Multiplex ligation-dependent probe amplification versus fluorescent in situ hybridization for screening RB1 copy number variations in Egyptian patients with retinoblastoma.

BACKGROUND: Retinoblastoma (RB) is the most common primary intraocular malignant tumor in children. RB is mostly caused by biallelic mutations in RB1 and occurs in hereditary and non-hereditary forms according to the "two-hit" theory. RB1 mutations comprise point mutations, indels, large deletions, and duplications. Genetic testing is essential for the comprehensive treatment and management of patients with RB. AIM: The aim was to evaluate RB1 copy number variations (CNVs) using MLPA versus FISH assays in group of Egyptian patients with RB. RESULTS: 16.67% showed an RB1 deletion, abnormal methylation status, or both. CONCLUSION: Our results suggested MLPA is a fast, reliable, and powerful method and should be used as a first-line screening tool for detecting RB1 CNVs in patients with RB. Moreover, MLPA is advantageous as it evaluates the methylation status/inactivation of RB1, not possible by FISH.

Genetic Implications in High-Risk Pregnancy and Its Outcome: A 2-Year Study.

OBJECTIVE: The aim of this study is to evaluate high-risk pregnant females' offspring as regard the presence of any medical condition, hereditary disorder, or major anomaly as well as to document parental sociodemographic characteristics and compliance with follow-up schedules of fetal medicine and clinical genetic clinics. STUDY DESIGN: This prospective 2-year cohort study of neonates and infants reported the referral indications, investigations, and diagnoses obtained through prenatal and postnatal examinations. It also reported their parental follow-up vigilance. RESULTS: Of the 811 infants of high risk females referred 460 (56.7%) came for assessment. Mean parental consanguinity and endogamy were 67 and 71.3%, respectively. All pregnant mothers underwent first-trimester biochemical testing (plasma protein-A, α-fetoprotein [AFP], human chorionic gonadotropin [hCG]) and serial ultrasound examinations. Seventy mothers needed second-trimester biochemical testing (AFP, hCG, and estriol). Sixty-two mothers underwent amniocentesis where G-banding karyotype, fluorescence in situ hybridization and targeted molecular testing for the specific gene mutation of single gene disorders were conducted according to suspected disorders. High quality fetal ultrasound was performed when brain malformations were suspected, while 16 fetuses required brain MRI examination. Mean age of newborns at first examination was 26.5 days. They were grouped according to the maternal indication for referral. Upon examination, 18 neonates had confirmed congenital malformations/genetic disorders. Five of them were diagnosed prenatally. In four other fetuses with single gene disorder, the molecular diagnosis of their affected siblings was not established prior to this pregnancy; thus, prenatal diagnosis was not possible. The remaining nine cases were diagnosed postnatally. CONCLUSION: Parental consanguinity and endogamy were increased among high-risk pregnancies. Public awareness about potential adverse effects of consanguineous marriages and the importance of genetic testing are imperative. A structured multidisciplinary team of specialists in fetal medicine, clinical genetics, and neonatology provides good genetic services. Expansion and financial support of these services are urgently required. KEY POINTS: · A multidisciplinary team provides good genetic services in high-risk pregnancies.. · Parental consanguinity and endogamy are increased among high-risk pregnancies.. · Increased public awareness about genetic testing importance and financial support are imperative..

Further Evidence of a Continuum in the Clinical Spectrum of Dominant PIEZO2-Related Disorders and Implications in Cerebellar Anomalies.

Introduction: Pathogenic variants in the PIEZO family member 2 (PIEZO2) gene are known to cause Gordon syndrome (GS), Marden-Walker syndrome (MWS), and distal arthrogryposis type 5 (DA5). Out of these, MWS has a recognizable phenotype that can be discerned easily, but the distinction between GS and DA5 is less evident. Few children with pathogenic PIEZO2 variants have been reported to show posterior fossa anomalies. Methods and Results: By candidate gene targeting guided by proper clinical evaluation and neuroimaging findings, a patient with classic MWS harboring a de novo novel variant (c.8237G>A, p.W2746*) in the C-terminal region of PIEZO2 was identified. In addition, another girl with the typical clinical features of GS is also described carrying the most prevalent reported variant (c.8057G>A, p.R2686H) in PIEZO2. The brain MRI of the 2 patients showed Dandy-Walker malformation (DWM). Diffusion tensor imaging visualized anteroposterior and downward aligned thin middle cerebellar peduncle. The association of DWM with arthrogryposis in the presence of PIEZO2 variants remains quite interesting and provides more evidence that PIEZO2 plays a role in the development of hindbrain although the underlying mechanism remains unclear. Moreover, the 2 girls had distinct foot patterning in the form of shortening of the first and fifth toes. Conclusion: Phenotype analysis and a comprehensive review of the literature strongly support the previously published data and corroborate the evidence that heterozygous PIEZO2-related disorders represent a continuum with overlapping phenotypic features.

Chromosome 9p terminal deletion in nine Egyptian patients and narrowing of the critical region for trigonocephaly.

BACKGROUND: This study aimed to delineate the clinical phenotype of patients with 9p deletions, pinpoint the chromosomal breakpoints, and identify the critical region for trigonocephaly, which is a frequent finding in 9p terminal deletion. METHODS: We investigated a cohort of nine patients with chromosome 9p terminal deletions who all displayed developmental delay, intellectual disability, hypotonia, and dysmorphic features. Of them, eight had trigonocephaly, seven had brain anomalies, seven had autistic manifestations, seven had fair hair, and six had a congenital heart defect (CHD). RESULTS: Karyotyping revealed 9p terminal deletion in all patients, and patients 8 and 9 had additional duplication of other chromosomal segments. We used six bacterial artificial chromosome (BAC) clones that could identify the breakpoints at 17-20 Mb from the 9p terminus. Array CGH identified the precise extent of the deletion in six patients; the deleted regions ranged from 16 to 18.8 Mb in four patients, patient 8 had an 11.58 Mb deletion and patient 9 had a 2.3 Mb deletion. CONCLUSION: The gene deletion in the 9p24 region was insufficient to cause ambiguous genitalia because six of the nine patients had normal genitalia. We suggest that the critical region for trigonocephaly lies between 11,575 and 11,587 Mb from the chromosome 9p terminus. To the best of our knowledge, this is the minimal critical region reported for trigonocephaly in 9p deletion syndrome, and it warrants further delineation.

Clinical and Cytogenomic Characterization of De Novo 11p14.3-p15.5 Duplication Associated with 18q23 Deletion in an Egyptian Female Infant.

Paternal microduplication of 11p14.3-p15.5 causes the clinical manifestations of Beckwith-Wiedemann syndrome (BWS), while microdeletion of 18q23-ter is clinically characterized by short stature, congenital malformations, and developmental delay. We describe a 15-month-old girl presenting with protruding tongue, dysmorphic facial features, moderate developmental delay, umbilical hernia, hypotonia, mild-to-moderate pulmonary hypertension, small patent ductus arteriosus, and mild ventricular septal hypertrophy. Brain magnetic resonance imaging showed mild atrophic changes. Chromosomal analysis revealed 46, XX, add(18)(q23). Fluorescence in situ hybridization using subtelomere 18q and whole chromosome painting 18 showed subtelomere deletion in 18q, and the add segment was not derived from chromosome 18. Microarray-based comparative genomic hybridization detected a 22 Mb duplication of chromosome 11p15.5p14.3 and a 3.7 Mb deletion of chromosome 18q23. The phenotype of the chromosomal rearrangements is probably resulted from a combination of dosage-sensitive genes. Our patient had clinical manifestations of both 18q deletion and BWS.

Clinical Variability of Pallister-Killian Syndrome in Two Egyptian Patients.

Pallister-Killian syndrome (PKS) is a rare sporadic genetic disorder caused by a mosaic tetrasomy of chromosome 12p, which mainly manifests with craniofacial dysmorphism, intellectual disability (ID), auditory disturbance, epilepsy, and a variety of congenital malformations. The diagnosis of PKS can be complicated due to the phenotypic variation, and an overlap with other syndromes makes the molecular cytogenetic test necessary for a correct diagnosis. We identified two unrelated patients with typical facial features of PKS, including bitemporal alopecia, hypertelorism, and abnormal ears. Furthermore, the two patients had pigmentary skin anomalies, broad and short hands and fingers, and hypotonia. However, they differed in the degree of ID and ophthalmological findings. Patient 1 showed profound ID and poor macular function, whereas patient 2 had moderate ID and normal fundus. Mosaic tetrasomy of chromosome 12p was found in 40 and 25% of the cells of patients 1 and 2, respectively, by fluorescent in situ hybridization of cultured skin fibroblasts. The higher percentage of mosaic cells with tetrasomy 12p found in patient 1 may explain the severe phenotype. This report expands the clinical manifestations of PKS and highlights the variable expressivity of clinical features in relation to the cytogenetics findings.

Microcephalic osteodysplastic primordial dwarfism type II: Additional nine patients with implications on phenotype and genotype correlation.

PCNT encodes a large coiled- protein localizing to pericentriolar material and is associated with microcephalic osteodysplastic primordial dwarfism type II syndrome (MOPD II). We report our experience of nine new patients from seven unrelated consanguineous Egyptian families with the distinctive clinical features of MOPD II in whom a customized NGS panel showed homozygous truncating variants of PCNT. The NGS panel results were validated thereafter using Sanger sequencing revealing three previously reported and three novel PCNT pathogenic variants. The core phenotype appeared homogeneous to what had been reported before although patients differed in the severity showing inter and intra familial variability. The orodental pattern showed atrophic alveolar ridge (five patients), rootless tooth (four patients), tooth agenesis (three patients), and malformed tooth (three patients). In addition, mesiodens was a novel finding found in one patient. The novel c.9394-1G>T variant was found in two sibs who had tooth agenesis. CNS anomalies with possible vascular sequelae were documented in two male patients (22.2%). Simplified gyral pattern with poor development of the frontal horns of lateral ventricles was seen in four patients and mild thinning of the corpus callosum in two patients. Unilateral coronal craniosynstosis was noted in one patient and thick but short corpus callosum was an unusual finding noted in another. The later has not been reported before. Our results refine the clinical, neuroradiological, and orodental features and expand the molecular spectrum of MOPD II.

Erratum: Clinical Variability of Pallister-Killian Syndrome in Two Egyptian Patients.

[This corrects the article DOI: 10.1055/s-0039-3400489.].

Lenz-Majewski syndrome in a patient from Egypt.

Lenz-Majewski syndrome (LMS) is an extremely rare type of cutis laxa caused by dominant mutations in PTDSS1 gene. We report an Egyptian patient who presented with cutis laxa, brachydactyly, and progeroid features. LMS syndrome was suspected and a previously reported de novo heterozygous missense mutation (c.284G > T, p.R95L) in PTDSS1 was identified. To the best of our knowledge, nine molecularly proven patients with LMS from different ethnicities have been reported. Our patient is the first report from the Middle East and the tenth molecularly proven patient reported to date. His clinical features were in accordance with LMS syndrome. In addition, his hands X-ray images showed hypoplastic or absent middle and proximal phalanges but sparing the thumbs. This hand patterning was similarly observed before. Further, he had relatively large and convex fingernails. Our report highlights this unique hand patterning and suggests these signs should be considered among the diagnostic criteria of LMS. Further reports of patients with PTDSS1 mutations are necessary to further elucidate the detailed clinical features of LMS syndrome.

Phenotypic and molecular insights into PQBP1-related intellectual disability.

We report two discordant clinical and imaging features in four male patients from two unrelated families of Egyptian descent with hemizygous pathogenic variants in PQBP1. The three patients of the first family displayed the typical features underlying PQBP1 such as the long triangular face, bulbous nose, hypoplastic malar region, and micrognathia, which were subsequently confirmed using targeted sequence analysis that showed a previously reported nonsense mutation c.586C>T p.R196*. Whole exome sequencing identified a novel missense PQBP1 variant c.530G>A:p.R177H in the second family, in which the index patient presented with intellectual disability and dysmorphic facial features reminiscent of Kabuki-like syndrome and his brain magnetic resonance imaging revealed partial agenesis of corpus callosum, mild vermis, and brainstem hypoplasia. These imaging features are distinct from the previously described with a well-known phenotype that is already known for PQBP1. This report expands the phenotypic spectrum of PQBP1-related disorders and is the second reported missense PQBP1 variant. Further, it highlights the possible role of PQBP1 in hindbrain development.

Magnetic resonance imaging of developmental facial paresis: a spectrum of complex anomalies.

PURPOSE: Despite its clinical implications, the MRI features of developmental facial paresis (DFP) were described in a few case reports. This study aims to describe MRI features of DFP in relation to the embryological development with a proposed radiological new grading system. METHODS: The clinical records and MRI of the brain and internal auditory canal of 11 children with DFP were retrospectively reviewed. The following sequences were analyzed: axial, oblique sagittal SPACE of the internal auditory canal and brainstem; axial T2, T1WI and coronal T2WI of the brain. The severity of the maldevelopment of the seventh nerve was graded from 0 to 4: 0 = no abnormalities, 1 = unilateral facial nerve hypoplasia, 2 = unilateral facial nerve aplasia, 3 = aplasia or hypoplasia involving facial nerves on both sides, and 4 = facial nerve aplasia or hypoplasia associated with other cranial nerve palsy. RESULTS: Isolated facial nerve palsy was diagnosed in seven patients. It was of grade 1 in five and grade 3 in two. Hypoplasia of the nerve with interrupted course was encountered in two cases. Other associated cranial nerve abnormalities (grade 4) were seen in four patients; two of them were diagnosed previously as Moebius syndrome. In addition to inner ear anomalies, middle and external ear and parotid gland anomalies were described. CONCLUSION: To our knowledge, this is the largest series of patients with DFP that represents a continuum of isolated and combined malformations. Understanding of embryological basis can give insights into the anomalous development of the facial nerve.

Identification of a novel homozygous ALX4 mutation in two unrelated patients with frontonasal dysplasia type-2.

We report two unrelated boys with frontonasal dysplasias type-2 (FND-2) who shared an identical novel homozygous ALX4 mutation c.291delG (p.Q98Sfs*83). Both patients presented with a large skull defect but one had bilateral parietal meningocele-like cysts that lie along with the bony defect and increased in size with age. Scalp alopecia, hypertelorism, and clefted alae nasi were also detected in both of them. Furthermore, impalpable gonads were noted, being unilateral in one and bilateral in the other. Neuroimaging showed small dysplastic occipital lobes with dysgyria and midline subarachnoid cyst. Additional dysplastic corpus callosum and small cerebellar vermis were observed in one patient. Parietal foramina were noted in the parents of one patient. Our findings highlight the dosage effect of ALX4 and underscore the challenges of prenatal genetic counseling. Further, the indirect role of ALX4 in the development of the occipital lobe and posterior fossa is discussed.

Further delineation of the oculoauricular syndrome phenotype: A new family with a novel truncating HMX1 mutation.

Biallelic HMX1 mutations cause a very rare autosomal recessive genetic disorder termed as oculoauricular syndrome (OAS) because it is characterized only by the combination of eye and ear anomalies. We identified a new family bringing to three the total families reported with this disorder. Our proband presented with anteriorly protruded ears and malformed ear pinnae in association with microphthalmia, congenital cataract, microcornea, and iris and optic disc colobomata. Additionally, he had high and broad forehead with asymmetry giving a recognizable facial gestalt. Further, short left mandibular ramus and bifid cingulum in the boy and short right mandibular ramus in his father were observed. Mutation analysis revealed a novel homozygous nonsense mutation c.487G>T in the second exon of the HMX1 that predicted to introduce a premature stop codon at position 163 (p.E163*). Parents showed the heterozygous state of the detected mutation. Investigations in a process as complex as craniofacial development suggest that there are still additional, as yet unidentified, genes that play in orchestrate to determine the final phenotype.

Lipoid proteinosis: A clinical and molecular study in Egyptian patients.

Lipoid proteinosis (LP) is an autosomal recessive disorder caused by the loss of function of ECM1 gene. Clinical features include varying degrees of skin thickening, hoarseness of voice and less frequently neuropsychiatric abnormalities. Twelve patients from ten unrelated families with a clinical diagnosis of lipoid proteinosis were enrolled in this study. Extraction of DNA samples of the 12 patients and their parents from peripheral blood by standard methods was performed. Polymerase chain reaction (PCR) amplification of the ECM1 gene was conducted using eight pairs of primers spanning over the 10 exons and splice junctions. Patients exhibited a variety of clinical manifestations with skin affection and hoarseness of voice being the consistent feature. We identified five novel homozygous insertion, small deletion, missense, and splice site mutations as well as two homozygous previously published splice site mutation c.70+1G>C in intron 1 and c.1305-2A>G in intron 8. The specific mutations were: c.10_11insC in exon 1, c.690_691delAG in exon 6, c.734G>A in exon 7, c.1286_1287delAA in exon 8 and c.1393-1G>T in intron 9. The novel mutations c.1393-1G>T and c.10_11insC occurred in three (30%) and two (20%) unrelated patients of the studied families, respectively. Further studies may designate an increased frequency of these mutations among Egyptian LP patients. Identification of pathogenic ECM1 mutations is important for accurate diagnosis and proper genetic counseling.

Clinical features of SMARCA2 duplication overlap with Coffin-Siris syndrome.

Coffin-Siris syndrome is a rare congenital malformation and intellectual disability syndrome. Mutations in at least seven genes have been identified. Here, we performed copy number analysis in 37 patients with features of CSS in whom no causative mutations were identified by exome sequencing. We identified a patient with a 9p24.3-p22.2 duplication and another patient with the chromosome der(6)t(6;9)(p25;p21)mat. Both patients share a duplicated 15.8-Mb region containing 46 protein coding genes, including SMARCA2. Dominant negative effects of SMARCA2 mutations may contribute to Nicolaides-Baraitser syndrome. We conclude that their features better resemble Coffin-Siris syndrome, rather than Nicolaides-Baraitser syndrome and that these features likely arise from SMARCA2 over-dosage. Pure 9p duplications (not caused by unbalanced translocations) are rare. Copy number analysis in patients with features that overlap with Coffin-Siris syndrome is recommended to further determine their genetic aspects. © 2016 Wiley Periodicals, Inc.

De Novo Mutation in ABCC9 Causes Hypertrichosis Acromegaloid Facial Features Disorder.

A 13-year-old Egyptian girl with generalized hypertrichosis, gingival hyperplasia, coarse facial appearance, no cardiovascular or skeletal anomalies, keloid formation, and multiple labial frenula was referred to our clinic for counseling. Molecular analysis of the ABCC9 gene showed a de novo missense mutation located in exon 27, which has been described previously with Cantu syndrome. An overlap between Cantu syndrome, acromegaloid facial syndrome, and hypertrichosis acromegaloid facial features disorder is apparent at the phenotypic and molecular levels. The patient reported here gives further evidence that these syndromes are an expression of the ABCC9-related disorders, ranging from hypertrichosis and acromegaloid facies to the severe end of Cantu syndrome.

Expanding the mutation and clinical spectrum of Roberts syndrome.

Roberts syndrome and SC phocomelia syndrome are rare autosomal recessive genetic disorders representing the extremes of the spectrum of severity of the same condition, caused by mutations in ESCO2 gene. We report three new patients with Roberts syndrome from three unrelated consanguineous Egyptian families. All patients presented with growth retardation, mesomelic shortening of the limbs more in the upper than in the lower limbs and microcephaly. Patients were subjected to clinical, cytogenetic and radiologic examinations. Cytogenetic analysis showed the characteristic premature separation of centromeres and puffing of heterochromatic regions. Further, sequencing of the ESCO2 gene identified a novel mutation c.244_245dupCT (p.T83Pfs*20) in one family besides two previously reported mutations c.760_761insA (p.T254Nfs*27) and c.764_765delTT (p.F255Cfs*25). All mutations were in homozygous state, in exon 3. The severity of the mesomelic shortening of the limbs and craniofacial anomalies showed variability among patients. Interestingly, patient 1 had abnormal skin hypopigmentation. Serial fetal ultrasound examinations and measurements of long bones diagnosed two affected fetuses in two of the studied families. A literature review and case comparison was performed. In conclusion, we report a novel ESCO2 mutation and expand the clinical spectrum of Roberts syndrome.

Mutation in WDR4 impairs tRNA m(7)G46 methylation and causes a distinct form of microcephalic primordial dwarfism.

BACKGROUND: Primordial dwarfism is a state of extreme prenatal and postnatal growth deficiency, and is characterized by marked clinical and genetic heterogeneity. RESULTS: Two presumably unrelated consanguineous families presented with an apparently novel form of primordial dwarfism in which severe growth deficiency is accompanied by distinct facial dysmorphism, brain malformation (microcephaly, agenesis of corpus callosum, and simplified gyration), and severe encephalopathy with seizures. Combined autozygome/exome analysis revealed a novel missense mutation in WDR4 as the likely causal variant. WDR4 is the human ortholog of the yeast Trm82, an essential component of the Trm8/Trm82 holoenzyme that effects a highly conserved and specific (m(7)G46) methylation of tRNA. The human mutation and the corresponding yeast mutation result in a significant reduction of m(7)G46 methylation of specific tRNA species, which provides a potential mechanism for primordial dwarfism associated with this lesion, since reduced m(7)G46 modification causes a growth deficiency phenotype in yeast. CONCLUSION: Our study expands the number of biological pathways underlying primordial dwarfism and adds to a growing list of human diseases linked to abnormal tRNA modification.