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Spinocerebellar disorders are a vast group of rare neurogenetic conditions, generally characterized by overlapping clinical symptoms including progressive cerebellar ataxia, spastic paraparesis, cognitive deficiencies, skeletal/muscular and ocular abnormalities. The objective of the present study is to identify the underlying genetic causes of the rare spinocerebellar disorders in the Pakistani population. Herein, nine consanguineous families presenting different spinocerebellar phenotypes have been investigated using whole exome sequencing. Sanger sequencing was performed for segregation analysis in all the available individuals of each family. The molecular analysis of these families identified six novel pathogenic/likely pathogenic variants; ZFYVE26: c.1093del, SACS: c.1201C>T, BICD2: c.2156A>T, ALS2: c.2171-3T>G, ALS2: c.3145T>A, and B4GALNT1: c.334_335dup, and three already reported pathogenic variants; FA2H: c.159_176del, APTX: c.689T>G, and SETX: c.5308_5311del. The clinical features of all patients in each family are concurrent with the already reported cases. Hence, the current study expands the mutation spectrum of rare spinocerebellar disorders and implies the usefulness of next-generation sequencing in combination with clinical investigation for better diagnosis of these overlapping phenotypes.

Intellectual disability (ID) is a condition of significant limitation of cognitive functioning and adaptive behavior, with 50% of etiology attributed to genetic predisposition. We recruited two consanguineous Pakistani families manifesting severe ID and developmental delay. The probands were subjected to whole exome sequencing (WES) and variants were further prioritized based on population frequency, predicted pathogenicity and functional relevance. The WES data analysis identified homozygous pathogenic variants in genes MBOAT7 and TRAPPC9. The pathogenicity of the variants was supported by co-segregation analysis and in silico tool. The findings of this study expand mutation spectrum and provide additional evidence to the role of MBOAT7 and TRAPPC9 in causation of ID.

A limiting factor for the identification of disease mechanisms and development of new therapies has been the access to a model system/s that can faithfully recapitulate key features of the disease and more precise clinical translations of new treatments. Stem cells in this regard are very promising, but the ethical issues related to totipotent embryonic stem cells and functional constraints to unipotent somatic stem cells have led to focus on induced pluripotent stem cells to avoid both functional and ethical constraints. The introduction of human Induced Pluripotent Stem Cell (iPSC) technology provides a model system to replicate diseases in humans. In this technology, human somatic cells can be “reprogrammed” by the transgene expression of four transcription factors into stem cells called iPSC. In this chapter, it will be discussed how iPSCs can be used for disease modelling, drug discovery and regenerative medicine.

Intellectual disability (ID) is caused by the disruption of neurodevelopmental processes. Its diagnosis and severity are defined in terms of an Intelligence Quotient score of

Objective: The objective of this study was to evaluate the frequencies and pattern of partial edentulism according to Kennedy’s classification in local population and its association with gender or arch type. Methodology: A cross-sectional study was conducted on 214 patients who visited Outpatient department, Nishtar Institute of Dentistry, Multan from 15-31st January, 2022. Non-probability consecutive sampling was employed. Partially dentate patients of age groups from 21 year onward were included in the study whereas completely edentulous patients or having fixed-prosthesis were not. Pattern of edentulism was evaluated by inspection and visual examination of the patient. Classification of arches was done according to Kennedy’s classification in combination with Applegate’s rules. To avoid complications, modifications were not considered. Data were analyzed using SPSS version 22 was used to analyze data and, frequencies and percentages were calculated along with association between the Kennedy’s class and other variables. Results: Of the 214 subjects, 108 (50.5%) were male and 106 (49.5%) were female. Majority (25.2%, n=54) of the patients were in their 30s followed by 24.8% in their forties (fig 1). In majority (65.4%, n=140) of the patients Kennedy’s class III was seen (fig 2). There was no significant association of Kennedy’s class with arch type (p=0.09) or gender (p=0.78). Conclusion: Kennedy’s class III was the most found partial edentulism pattern. No significant association was found between Kennedy’s class and gender or arch type. Key Words: Partial edentulism, Kennedy’s classification, Applegate’s rule, tooth loss

Jawad syndrome is a multiple congenital anomaly and intellectual disability syndrome with mutation in RBBP8 reported only in two families. Here, we report on two new families from Pakistan and identified a previously reported variant in RBBP8, NM_002894.3:c.1808-1809delTA. We could show that this mutation impairs splicing resulting in two different abnormal transcripts. Finally, we could verify a shared haplotype among all four families and estimate the founder event to have occurred some 24 generations ago.

Schizophrenia is a disabling neuropsychiatric disorder of adulthood onset with high heritability. Worldwide collaborations have identified an association of ~270 common loci, with small individual effects and hence weak clinical implications. The recent technological feasibility of exome sequencing enables the identification of rare variants of high penetrance that refine previous findings and improve risk assessment and prognosis. We recruited two multiplex Pakistani families, having 11 patients and 19 unaffected individuals in three generations. We performed genome-wide SNP genotyping, next-generation mate pairing and whole-exome sequencing of selected members to unveil genetic components. Candidate variants were screened in unrelated cohorts of 508 cases, 300 controls and fifteen families (with 51 affected and 47 unaffected individuals) of Pakistani origin. The structural impact of substituted residues was assessed through in silico modeling using iTASSER. In one family, we identified a rare novel microduplication (5q14.1_q14.2) encompassing critical genes involved in glutamate signaling, such as CMYA5, HOMER and RasGRF2. The second family segregates two ultra-rare, predicted pathogenic variants in the GRIN2A (NM_001134407.3: c.3505C>T, (p.R1169W) and in the NRG3 NM_001010848.4: c.1951G>A, (p.E651K). These genes encode for parts of AMPA and NMDA receptors of glutamatergic neurotransmission, respectively, and the variants are predicted to compromise protein function by destabilizing their structures. The variants were absent in the aforementioned cohorts. Our findings suggest that rare, highly penetrant variants of genes involved in glutamatergic neurotransmission are contributing to the etiology of schizophrenia in these families. It also highlights that genetic investigations of multiplex, multigenerational families could be a powerful approach to identify rare genetic variants involved in complex disorders.

Hereditary Spastic paraplegias (HSPs) are heterogeneous group of degenerative disorders characterized by progressive weakness and spasticity of the lower limbs, combined with additional neurological features. This study aimed to identify causative gene variants in two nonrelated consanguineous Pakistani families segregating HSP. Whole exome sequencing (WES) was performed on a total of five individuals from two families including four affected and one phenotypically normal individual. The variants were validated by Sanger sequencing and segregation analysis. In family A, a novel homozygous variant c.604G > A (p.Glu202Lys) was identified in the CYP2U1 gene with clinical symptoms of SPG56 in 3 siblings. Whereas, a previously reported variant c.5769delT (p.Ser1923Argfs*28) in the SPG11 gene was identified in family B manifesting clinical features of SPG11 in 3 affected individuals. Our combined findings add to the clinical and genetic variability associated with CYP2U1 and SPG11 variants highlighting the complexity of HSPs. These findings further emphasize the usefulness of WES as a powerful diagnostic tool.

PURPOSE: We aimed to define a novel autosomal recessive neurodevelopmental disorder, characterize its clinical features, and identify the underlying genetic cause for this condition.METHODS: We performed a detailed clinical characterization of 19 individuals from nine unrelated, consanguineous families with a neurodevelopmental disorder. We used genome/exome sequencing approaches, linkage and cosegregation analyses to identify disease-causing variants, and we performed three-dimensional molecular in silico analysis to predict causality of variants where applicable.RESULTS: In all affected individuals who presented with a neurodevelopmental syndrome with progressive microcephaly, seizures, and intellectual disability we identified biallelic disease-causing variants in Protocadherin-gamma-C4 (PCDHGC4). Five variants were predicted to induce premature protein truncation leading to a loss of PCDHGC4 function. The three detected missense variants were located in extracellular cadherin (EC) domains EC5 and EC6 of PCDHGC4, and in silico analysis of the affected residues showed that two of these substitutions were predicted to influence the Ca2+-binding affinity, which is essential for multimerization of the protein, whereas the third missense variant directly influenced the cis-dimerization interface of PCDHGC4.CONCLUSION: We show that biallelic variants in PCDHGC4 are causing a novel autosomal recessive neurodevelopmental disorder and link PCDHGC4 as a member of the clustered PCDH family to a Mendelian disorder in humans.

GPR56 gene is best known for its pivotal role in cerebral cortical development. Mutations in GPR56 give rise to cobblestone-like brain malformation, white matter changes and cerebellar dysplasia. This study aimed to identify causative variant in a consanguineous family having five individuals affected with developmental delay, mild to severe intellectual disability, speech impairment, strabismus and seizures. Whole exome sequencing was performed to identify mutation in affected individuals. Variants were filtered and further validated by Sanger sequencing and segregation analysis. A novel frameshift variant c.1601dupT leading to p.Ala535GlyfsTer17) was identified in GPR56 gene by whole exome sequencing and subsequent filtering. All five affected individuals were homozygous for the mutant allele while four asymptomatic individuals carried the variant in heterozygous state. Radiological findings of a representative patient presented features of GPR56-associated cobblestone like brain malformation. MRI findings suggested paucity of sulci, dilated ventricular system and brainstem atrophy. The microgyria were observed in a simplified gyral pattern (cobblestone). This single bp insertion, and the consequent frameshift, results in the truncation of GPR56 protein. This could result in a malformed cortex giving the brain a cobblestone like shape. Our study identified a 7th novel frameshift variant from Pakistani population in GPR56 gene, thus broadening mutation spectrum.

Congenital microcephaly is the clinical presentation of significantly reduced head circumference at birth. It manifests as both non-syndromic—microcephaly primary hereditary (MCPH)—and syndromic forms and shows considerable inter- and intrafamilial variability. It has been hypothesized that additional genetic variants may be responsible for this variability, but data are sparse. We have conducted deep phenotyping and genotyping of five Pakistani multiplex families with either MCPH (n = 3) or Seckel syndrome (n = 2). In addition to homozygous causal variants in ASPM or CENPJ, we discovered additional heterozygous modifier variants in WDR62, CEP63, RAD50 and PCNT—genes already known to be associated with neurological disorders. MCPH patients carrying an additional heterozygous modifier variant showed more severe phenotypic features. Likewise, the phenotype of Seckel syndrome caused by a novel CENPJ variant was aggravated to microcephalic osteodysplastic primordial dwarfism type II (MOPDII) in conjunction with an additional PCNT variant. We show that the CENPJ missense variant impairs splicing and decreases protein expression. We also observed centrosome amplification errors in patient cells, which were twofold higher in MOPDII as compared to Seckel cells. Taken together, these observations advocate for consideration of additional variants in related genes for their role in modifying the expressivity of the phenotype and need to be considered in genetic counseling and risk assessment. Higher Education of Commission (HEC) of Pakistan Center for Molecular Medicine Cologne - 38-RP Center for Molecular Medicine Cologne - 2635/8029/01 Center for Molecular Medicine Cologne- 2635/8326/01 Koeln Fortune Program, Faculty of Medicine, University of Cologne - 381/2020 WOS:000653928700001 PMID: 34068194 Q2

Congenital microcephaly is the clinical presentation of significantly reduced head circumference at birth. It manifests as both non-syndromic—microcephaly primary hereditary (MCPH)—and syndromic forms and shows considerable inter- and intrafamilial variability. It has been hypothesized that additional genetic variants may be responsible for this variability, but data are sparse. We have conducted deep phenotyping and genotyping of five Pakistani multiplex families with either MCPH (n = 3) or Seckel syndrome (n = 2). In addition to homozygous causal variants in ASPM or CENPJ, we discovered additional heterozygous modifier variants in WDR62, CEP63, RAD50 and PCNT—genes already known to be associated with neurological disorders. MCPH patients carrying an additional heterozygous modifier variant showed more severe phenotypic features. Likewise, the phenotype of Seckel syndrome caused by a novel CENPJ variant was aggravated to microcephalic osteodysplastic primordial dwarfism type II (MOPDII) in conjunction with an additional PCNT variant. We show that the CENPJ missense variant impairs splicing and decreases protein expression. We also observed centrosome amplification errors in patient cells, which were twofold higher in MOPDII as compared to Seckel cells. Taken together, these observations advocate for consideration of additional variants in related genes for their role in modifying the expressivity of the phenotype and need to be considered in genetic counseling and risk assessment.

International audience; Neurochondrin (NCDN) is a cytoplasmatic neural protein of importance for neural growth, glutamate receptor (mGluR) signaling, and synaptic plasticity. Conditional loss of Ncdn in mice neural tissue causes depressive-like behaviors, impaired spatial learning, and epileptic seizures. We report on NCDN missense variants in six affected individuals with variable degrees of developmental delay, intellectual disability (ID), and seizures. Three siblings were found homozygous for a NCDN missense variant, whereas another three unrelated individuals carried different de novo missense variants in NCDN. We assayed the missense variants for their capability to rescue impaired neurite formation in human neuroblastoma (SH-SY5Y) cells depleted of NCDN. Overexpression of wild-type NCDN rescued the neurite-phenotype in contrast to expression of NCDN containing the variants of affected individuals. Two missense variants, associated with severe neurodevelopmental features and epilepsy, were unable to restore mGluR5-induced ERK phosphorylation. Electrophysiological analysis of SH-SY5Y cells depleted of NCDN exhibited altered membrane potential and impaired action potentials at repolarization, suggesting NCDN to be required for normal biophysical properties. Using available transcriptome data from human fetal cortex, we show that NCDN is highly expressed in maturing excitatory neurons. In combination, our data provide evidence that bi-allelic and de novo variants in NCDN cause a clinically variable form of neurodevelopmental delay and epilepsy, highlighting a critical role for NCDN in human brain development.

Different mutations in the Growth/Differentiation Factor 5 gene (GDF5) have been associated with varying types of skeletal dysplasia, including Grebe type chondrodysplasia (GTC), Hunter-Thompson syndrome, Du Pan Syndrome and Brachydactyly type C (BDC). Heterozygous pathogenic mutations exert milder effects, whereas homozygous mutations are known to manifest more severe phenotypes. In this study, we report a GDF5 frameshift mutation (c.404delC) segregating over six generations in an extended consanguineous Pakistani family. The family confirmed that both GTC and BDC are part of the GDF5 mutational spectrum, with severe GTC associated with homozygosity, and with a wide phenotypic variability among heterozygous carriers, ranging from unaffected non-penetrant carriers, to classical BDC and to novel unclassified types of brachydactylies.

CDK5RAP2 gene encodes a centrosomal protein, highly expressed in fetal brain and essentially indispensable for its normal development, as biallelic mutations in it lead to primary microcephaly (MCPH). Despite being known as MCPH linked gene for more than a decade, the phenotypic spectrum of CDK5RAP2 mutations is still under explored as only eleven families have been reported worldwide. Here, we analyzed a consanguineous Pakistani MCPH family, characterized by moderate to severe intellectual disability, speech impairment, moderately short stature and sparse eyebrows. Whole exome sequencing of the proband identified a 2bp duplication in exon 34 of CDK5RAP2 that causes frame-shift, leading to a premature stop codon. The resultant transcript is resistant to nonsense mediated decay, suggesting that the mutation leads to a truncated protein lacking C-terminal domains; CDK5R1, and Cnn motif 2 (CM2), required for its localization to centrosome and Golgi Apparatus. Clinical variability observed in the family highlights the importance of further detailed clinical description of patients with CDK5RAP2 mutations.

Objective: Autosomal recessive primary microcephaly (MCPH) is a rare condition characterized by a reduced cerebral cortex accompanied with intellectual disability. Mutations in 17 genes have been shown to cause this phenotype. Recently, mutations in CIT, encoding CRIK (Citron Rho-interacting kinase) — a component of the central spindle matrix, were added. We aimed at identifying novel MCPH-associated genes and exploring their functional role in pathogenesis. Methods: Linkage analysis and whole-exome sequencing were performed in consanguineous and nonconsanguineous MCPH families to identify disease-causing variants. Functional consequences were investigated by RNA studies and on cellular level using immunofluorescence and microscopy. Results: We identified homozygous mutations in KIF14 (NM_014875.2;c.263T>A;pLeu88*, c.2480_2482delTTG;p.Val827del and c.4071G>A;p.Gln1357=) as the likely cause in three MCPH families. Further, in a patient presenting with a severe form of primary microcephaly and short stature, we identified compound heterozygous missense mutations in KIF14 (NM_014875.2;c.2545C>G;p.His849Asp and c.3662G>T;p.Gly1221Val). Three of the five identified mutations impaired splicing and two resulted in a truncated protein. Intriguingly, Kif14 knockout mice also showed primary microcephaly. Human kinesin-like protein KIF14, a microtubule motor protein, localizes at the midbody to finalize cytokinesis by interacting with CRIK. We found impaired localization of both KIF14 and CRIK at the midbody in patient-derived fibroblasts. Further, we observed a large number of binucleated and apoptotic cells — signs of failed cytokinesis that we also observed in experimentally KIF14-depleted cells. Interpretation: Our data corroborate the role of an impaired cytokinesis for the etiology of primary and syndromic microcephaly as has been proposed by recent findings on CIT mutations. This article is protected by copyright. All rights reserved.

Aim: Neuronal ceroid lipofuscinosis (NCLs) are the most common neurodegenerative disorders, with global incidence of 1 in 100,000 live births. NCLs affect central nervous system, primarily cerebellar and cerebral cortices. Juvenile neuronal ceroid lipofuscinosis (JNCL), also known as Batten disease, is the most common form of NCLs. JNCL is primarily caused by pathogenic mutations in CLN3 gene, which encodes a transporter transmembrane protein of uncertain function. The 1.02 kb deletion is the most common mutation in CLN3 that results in frame shift and a premature termination leading to nonfunctional protein. Here, we invetigated a large consanguineous family consisting of four affected individuals with clincal symptoms suggestive of Juvenile neuronal ceroid lipofuscinosis. Materials and methods: We conducted clinial and radilogical investigation of the family and performed NGS based Gene Panel sequencing comprising of five hundred and forty five candidate genes to characterize it at genetic level. Results: We identified a novel homozygous c.181_183delGAC mutation in the CLN3 gene seggregating witht the disorder in the family. The mutation induces in-frame deletion, deleting one amino acid (p.Asp61del) in CLN3 protein. The deleted amino acid aspartic acid plays an important role as general acid in enzymes active centers as well as in maintaining the ionic character of proteins. Conclusion: Our finding adds to genetic variability of Juvenile neuronal ceroid lipofuscinosis associated with CLN3 gene and a predicted CLN3 protein interacting domain site.

Biallelic and pathogenic variants in the RTTN gene, encoding the centrosomal protein Rotatin, are associated with variable degrees of neurodevelopmental abnormalities, microcephaly, and extracranial malformations. To date, no reported case has reached their third decade. Herein, we report on a consanguineous family with three adult members, age 43, 57, and 60 years respectively, with primary microcephaly, developmental delay, primordial dwarfism, and brachydactyly segregating a homozygous splice site variant NM_173630.3:c.5648-5T>A in RTTN. The variant RTTN allele results in a nonhypomorphic skipping of exon 42 and a frameshift [(NP_775901.3:p.Ala1883Glyfs*6)]. Brain MRI of one affected individual showed markedly reduced volume of cerebral lobes and enlarged sulci but without signs of neural migration defects. Our assessment of three adult cases with a biallelic RTTN variant shows that a predicted shortened Rotatin, lacking the C-terminal end, are associated with stationary clinical features into the seventh decade. Furthermore, our report adds brachydactyly to the phenotypic spectrum in this pleiotropic entity.

Primary microcephaly is a disorder characterized by a small head and brain associated with impaired cognitive capabilities. Mutations in 13 different genes encoding centrosomal proteins and cell cycle regulators have been reported to cause the disease. CASC5, a gene encoding a protein important for kinetochore formation and proper chromosome segregation during mitosis, has been suggested to be associated with primary microcephaly-4 (MCPH4). This was based on one mutation only and circumstantial functional evidence. By combining homozygosity mapping and whole-exome sequencing in an MCPH family from Pakistan, we identified a second mutation (NM_170589.4;c.6673-19T>A) in CASC5. This mutation induced skipping of exon 25 of CASC5 resulting in a frameshift and the introduction of a premature stop codon (p.Met2225Ilefs*7). The C-terminally truncated protein lacks 118 amino acids that encompass the region responsible for the interaction with the hMIS12 complex, which is essential for proper chromosome alignment and segregation. Furthermore, we showed a down-regulation of CASC5 mRNA and reduction of the amount of CASC5 protein by quantitative RT-PCR and western blot analysis, respectively. As a further sign of functional deficits, we observed dispersed dots of CASC5 immunoreactive material outside the metaphase plate of dividing patient fibroblasts. Normally, CASC5 is a component of the kinetochore of metaphase chromosomes. A higher mitotic index in patient cells indicated a mitotic arrest in the cells carrying the mutation. We also observed lobulated and fragmented nuclei as well as micronuclei in the patient cells. Moreover, we detected an altered DNA damage response with higher levels of γH2AX and 53BP1 in mutant as compared to control fibroblasts. Our findings substantiate the proposed role of CASC5 for primary microcephaly and suggest that it also might be relevant for genome stability.

Autosomal recessive primary microcephaly (MCPH) is a rare condition characterized by a reduced cerebral cortex accompanied with intellectual disability. Mutations in 17 genes have been shown to cause this phenotype. Recently, mutations in CIT, encoding CRIK (citron rho-interacting kinase)-a component of the central spindle matrix-were added. We aimed at identifying novel MCPH-associated genes and exploring their functional role in pathogenesis.Linkage analysis and whole exome sequencing were performed in consanguineous and nonconsanguineous MCPH families to identify disease-causing variants. Functional consequences were investigated by RNA studies and on the cellular level using immunofluorescence and microscopy.We identified homozygous mutations in KIF14 (NM_014875.2;c.263TA;pLeu88*, c.2480_2482delTTG; p.Val827del, and c.4071GA;p.Gln1357=) as the likely cause in 3 MCPH families. Furthermore, in a patient presenting with a severe form of primary microcephaly and short stature, we identified compound heterozygous missense mutations in KIF14 (NM_014875.2;c.2545CG;p.His849Asp and c.3662GT;p.Gly1221Val). Three of the 5 identified mutations impaired splicing, and 2 resulted in a truncated protein. Intriguingly, Kif14 knockout mice also showed primary microcephaly. Human kinesin-like protein KIF14, a microtubule motor protein, localizes at the midbody to finalize cytokinesis by interacting with CRIK. We found impaired localization of both KIF14 and CRIK at the midbody in patient-derived fibroblasts. Furthermore, we observed a large number of binucleated and apoptotic cells-signs of failed cytokinesis that we also observed in experimentally KIF14-depleted cells.Our data corroborate the role of an impaired cytokinesis in the etiology of primary and syndromic microcephaly, as has been proposed by recent findings on CIT mutations. Ann Neurol 2017;82:562-577.

Objective Schizophrenia is a chronic neuropsychiatric disease afflicting around 1.1% of the population worldwide. Recently, MIR137, CACNA1C, CSMD1, DRD2, and GRM3 have been reported as the most robustly emerging candidates involved in the etiology of schizophrenia. In this case control study, we performed an association analysis of rs1625579 (MIR137), rs1006737, rs4765905 (CACNA1C), rs10503253 (CSMD1), rs1076560 (DRD2), rs12704290, rs6465084, and rs148754219 (GRM3) in Pakistani population. Methods Schizophrenia was diagnosed on the basis of the Diagnostic and Statistical Manual of Mental Disorders 4th ed (DSM-IV). Detailed clinical information, family history of all patients and healthy controls were collected. RFLP based case control association study was performed in a Pakistani cohort of 508 schizophrenia patients and 300 healthy control subjects. Alleles and genotype frequencies were calculated using SPSS. Results A significant difference in the genotype and allele frequencies for rs4765905, rs1076560 and rs6465084 were found between the patients and controls (p=0.000). Conclusion This study provides substantial evidence supporting the role of CACNA1C, GRM3 and DRD2 as schizophrenia susceptibility genes in Pakistani population.

In recent years, several genes have been causally associated with epilepsy. However, making a genetic diagnosis in a patient can still be difficult, since extensive phenotypic and genetic heterogeneity has been observed in many monogenic epilepsies. This study aimed to analyze the genetic basis of a wide spectrum of epilepsies with age of onset spanning from the neonatal period to adulthood. A gene panel targeting 46 epilepsy genes was used on a cohort of 216 patients consecutively referred for panel testing. The patients had a range of different epilepsies from benign neonatal seizures to epileptic encephalopathies (EEs). Potentially causative variants were evaluated by literature and database searches, submitted to bioinformatic prediction algorithms, and validated by Sanger sequencing. If possible, parents were included for segregation analysis. We identified a presumed disease-causing variant in 49 (23%) of the 216 patients. The variants were found in 19 different genes including SCN1A, STXBP1, CDKL5, SCN2A, SCN8A, GABRA1, KCNA2, and STX1B. Patients with neonatal-onset epilepsies had the highest rate of positive findings (57%). The overall yield for patients with EEs was 32%, compared to 17% among patients with generalized epilepsies and 16% in patients with focal or multifocal epilepsies. By the use of a gene panel consisting of 46 epilepsy genes, we were able to find a disease-causing genetic variation in 23% of the analyzed patients. The highest yield was found among patients with neonatal-onset epilepsies and EEs.

Background Cerebral palsy (CP) is a heterogeneous neurodevelopmental disorder associated with intellectual disability in one-third of cases. Recent findings support Mendelian inheritance in subgroups of patients with the disease. The purpose of this study was to identify a novel genetic cause of paraplegic CP with intellectual disability in a consanguineous Pakistani family. Methods We performed whole-exome sequencing (WES) in two brothers with CP and intellectual disability. Analysis of AP4M1 mRNA was performed using quantitative real-time PCR on total RNA from cultured fibroblasts. The brothers were investigated clinically and by MRI. Results We identified a novel homozygous AP4M1 mutation c.194_195delAT, p.Y65Ffs*50 in the affected brothers. Quantitative RT-PCR analysis showed markedly reduced AP4M1 mRNA levels suggesting partial non-sense mediated mRNA decay. Several clinical and MRI features were consistent with AP-4 complex deficiency. However, in contrast to previously reported cases with AP4M1 mutations our patients show an aggressive behavior and a relatively late onset of disease. Conclusion This study shows an AP4M1 mutation associated with aggressive behavior in addition to mild dysmorphic features, intellectual disability, spastic paraparesis and reduced head circumference. Our findings expand the clinical spectrum associated with AP-4 complex deficiency and the study illustrates the importance of MRI and WES in the diagnosis of patients with CP and intellectual disability.

OBJECTIVE: Schizophrenia is a chronic neuropsychiatric disease afflicting around 1.1% of the population worldwide. Recently, MIR137, CACNA1C, CSMD1, DRD2, and GRM3 have been reported as the most robustly emerging candidates involved in the etiology of schizophrenia. In this case control study, we performed an association analysis of rs1625579 (MIR137), rs1006737, rs4765905 (CACNA1C), rs10503253 (CSMD1), rs1076560 (DRD2), rs12704290, rs6465084, and rs148754219 (GRM3) in Pakistani population.METHODS: Schizophrenia was diagnosed on the basis of the Diagnostic and Statistical Manual of Mental Disorders 4th ed (DSM-IV). Detailed clinical information, family history of all patients and healthy controls were collected. RFLP based case control association study was performed in a Pakistani cohort of 508 schizophrenia patients and 300 healthy control subjects. Alleles and genotype frequencies were calculated using SPSS.RESULTS: A significant difference in the genotype and allele frequencies for rs4765905, rs1076560 and rs6465084 were found between the patients and controls (p=0.000).CONCLUSION: This study provides substantial evidence supporting the role of CACNA1C, GRM3 and DRD2 as schizophrenia susceptibility genes in Pakistani population.