Clinical and neurogenetic characterisation of autosomal recessive RBL2-associated progressive neurodevelopmental disorder.

Retinoblastoma (RB) proteins are highly conserved transcriptional regulators that play important roles during development by regulating cell-cycle gene expression. RBL2 dysfunction has been linked to a severe neurodevelopmental disorder. However, to date, clinical features have only been described in six individuals carrying five biallelic predicted loss of function (pLOF) variants. To define the phenotypic effects of RBL2 mutations in detail, we identified and clinically characterized a cohort of 28 patients from 18 families carrying LOF variants in RBL2 , including fourteen new variants that substantially broaden the molecular spectrum. The clinical presentation of affected individuals is characterized by a range of neurological and developmental abnormalities. Global developmental delay and intellectual disability were uniformly observed, ranging from moderate to profound and involving lack of acquisition of key motor and speech milestones in most patients. Frequent features included postnatal microcephaly, infantile hypotonia, aggressive behaviour, stereotypic movements and non-specific dysmorphic features. Common neuroimaging features were cerebral atrophy, white matter volume loss, corpus callosum hypoplasia and cerebellar atrophy. In parallel, we used the fruit fly, Drosophila melanogaster , to investigate how disruption of the conserved RBL2 orthologueue Rbf impacts nervous system function and development. We found that Drosophila Rbf LOF mutants recapitulate several features of patients harboring RBL2 variants, including alterations in the head and brain morphology reminiscent of microcephaly, and perturbed locomotor behaviour. Surprisingly, in addition to its known role in controlling tissue growth during development, we find that continued Rbf expression is also required in fully differentiated post-mitotic neurons for normal locomotion in Drosophila , and that adult-stage neuronal re-expression of Rbf is sufficient to rescue Rbf mutant locomotor defects. Taken together, this study provides a clinical and experimental basis to understand genotype-phenotype correlations in an RBL2 -linked neurodevelopmental disorder and suggests that restoring RBL2 expression through gene therapy approaches may ameliorate aspects of RBL2 LOF patient symptoms.

Insights into the Value of Lyso-Gb1 as a Predictive Biomarker in Treatment-Naïve Patients with Gaucher Disease Type 1 in the LYSO-PROOF Study.

Gaucher disease (GD) is a rare autosomal recessive disorder arising from bi-allelic variants in the GBA1 gene, encoding glucocerebrosidase. Deficiency of this enzyme leads to progressive accumulation of the sphingolipid glucosylsphingosine (lyso-Gb1). The international, multicenter, observational "Lyso-Gb1 as a Long-term Prognostic Biomarker in Gaucher Disease"-LYSO-PROOF study succeeded in enrolling a cohort of 160 treatment-naïve GD patients from diverse geographic regions and evaluated the potential of lyso-Gb1 as a specific biomarker for GD. Using genotypes based on established classifications for clinical presentation, patients were stratified into type 1 GD (n = 114) and further subdivided into mild (n = 66) and severe type 1 GD (n = 48). Due to having previously unreported genotypes, 46 patients could not be classified. Though lyso-Gb1 values at enrollment were widely distributed, they displayed a moderate and statistically highly significant correlation with disease severity measured by the GD-DS3 scoring system in all GD patients (r = 0.602, p < 0.0001). These findings support the utility of lyso-Gb1 as a sensitive biomarker for GD and indicate that it could help to predict the clinical course of patients with undescribed genotypes to improve personalized care in the future.

The Mutational Landscape Of Genetic Cholestatic Diseases In Pakistani Children.

Objectives: To report the mutational landscape of a clinically diagnosed cohort of paediatric patients with cholestasis liver diseases. METHODS: The retrospective study was conducted at the University of Child Health Sciences, The Children Hospital, Lahore, Pakistan, from December 10, 2021, to March 31, 2022, and comprised data collected from the Paediatric Gastroenterology and Hepatology unit on demographics, clinical and laboratory findings related to children of either gender aged <12 years and diagnosed with cholestatic liver disease from July 2018 to June 2021. The diagnosis was based on clinical and biochemical findings, with no evidence of biliary atresia and metabolic liver disease. Molecular characterisation was done through whole exome sequencing. RESULTS: Of the 171 children evaluated, 92(53.8%) were diagnosed with genetic cholestatic disorders. There were 52(56%) boys and 41(44%) girls. The median age at presentation was 19.5 months (interquartile range: 51 months). Consanguinity was found in 82(88.1%) cases, and positive family history with one or more affected siblings was noted in 60(64.5%). Exome sequencing identified pathogenic mutations in 13 genes underlying the hereditary cholestasis; ATP8B1, ABCB11, ABCB4, TJP2, NR1H4, DCDC2, ACOX2, AKR1D1, HSD3B7, ABCC2, USP53, SLC10A1, and SLC51A. Of the 70 variants identified, 50(71.4%) were novel variants. The ABCB11-related hereditary cholestasis was the most frequent 27(29%), followed by ABCB4 (26(27.9%). Homozygosity was frequently seen in all except 8(8.6%) children, who had compound heterozygous pathogenic variants. There was no evidence of phenotypic expression in the carrier parents despite the severe nature of the respective mutations identified in the patients. CONCLUSIONS: Genetic heterogeneity of paediatric intrahepatic cholestasis showed recurrent and novel mutations.

Clinical and Genetic Description of Hereditary Chronic Pancreatitis in Pakistani Children.

BACKGROUND/AIMS: The purpose of this study was to identify the spectrum and frequency of pathogenic variants as well as the clinical and genetic insight of hereditary chronic pancreatitis in Pakistani children. MATERIALS AND METHODS: The deoxyribonucleic acid of affected probands of 44 unrelated Pakistani families, having hereditary chronic pancreatitis-affected children, were subjected to massive parallel sequencing for candidate reported genes (SPINK1, PRSS1, CFTR, CPA1, CTRC, CBS, AGL, PHKB, and LPL). Data were analyzed using different bioinformatics tools for the variants and in-silico analysis. All the identified variants were validated by direct sequencing of the targeted exons in the probands and their parents. RESULTS: There were 50 patients included in this study with confirmed hereditary chronic pancreatitis. Nine known mutations in SPINK1, PRSS1, CFTR, CTRC, CBS, and AGL genes, and 10 novel variants in LPL, CFTR, CTR, and PHKB genes were identified. The identified variants were found in heterozygous, compound heterozygous, and trans-heterozygous forms, with rare allele frequency in the normal population. The novel variants were [c.378C>T(p.Lys126Asn) and c.719G>A(p.Arg240Gln) in CTRC, c.586-3C>A and c.763A>G(p.Arg255Gly) in CPA1, c.1160_1161insT(p.Lys387Asnfs*26), c.784C>T(p.Gln262*), c.1139+1G>A, c.175G>A(p.Gly59Arg) in LPL, c.388C>G(p.leu130val) in CFTR, and c.2327G>A(p.Arg776His in PHKB)]. The phenotypic characteristics were variable and correlated with the relevant variant. CONCLUSIONS: The genetic composition plays a significant role in the predisposition of hereditary chronic pancreatitis. The clinical presentation varies with the genetic determinant involved. This information would help in building up a diagnostic algorithm for our population that can be used for genetic screening services in affected cohorts.

Corticosterone Methyl Oxidase Type 1 (CMO1) Deficiency Due to CYP11B2 Mutation: Two Case Reports.

Aldosterone synthase deficiency (ASD) is a rare autosomal recessive condition due to an inactivating mutation in CYP11B2. There are two types of ASD depending upon level of defect in aldosterone synthesis, corticosterone methyl oxidase type 1 (CMO 1) and type 2 (CMO 2) deficiency. We are reporting two cases of CMO 1 deficiency presented with failure to thrive. Both cases were born to consanguineous parents and presented at around 17 months and 15 months with complaints of repeated vomiting and failure to thrive. They were found to have persistent hyponatremia, hyperkalemia, low aldosterone level, raised renin levels, normal cortisol and normal 17 hydroxyprogesterone level, suggesting the diagnosis of isolated aldosterone deficiency. Whole exome sequencing revealed that Case 1 is carrying a novel homozygous mutation in CYP11B2, c.1391_1393dup p.(Leu464dup) and Case 2 has a homozygous pathogenic variant in CYP11B2, c.922T>C p.(Ser308Pro), confirming the diagnosis of CMO 1 deficiency in both cases. After initial stabilization, both cases were started on oral fludrocortisone. They responded well and showed a good catch-up in growth and development. Aldosterone synthase deficiency is a rare condition, but it shall be suspected in infants presented with failure to thrive, hyponatremia and hyperkalemia without pigmentation and virilization.

Secondary findings in a large Pakistani cohort tested with whole genome sequencing.

Studies on genomic secondary findings (SFs) are diverse in participants' characteristics, sequencing methods, and versions of the ACMG SF list. Based on whole genome sequencing and the version 3.1 of the ACMG SF list, we studied SFs in 863 individuals from five different regions in Pakistan. We identified 24 ACMG SFs in 23 (2.7%) of 863 individuals: 18 of 24 were related to cardiovascular disease and four to cancer syndromes. In addition to ACMG SFs, we identified 16 (1.9%) participants with pathogenic and likely pathogenic variants in genes that were not related to the participants' clinical conditions but with clear medical actionability (non-ACMG SFs): 4 of 16 were related to eye diseases, two to metabolic disorders, and two to urinary system disorders. By testing a large Pakistani cohort with whole genome sequencing, we concluded that in countries such as Pakistan, the ACMG SF list could be expanded, and our non-ACMG SF list is one example.

Clinical spectrum and diagnostic challenges of vitamin D dependent rickets type 1A (VDDR1A) caused by CYP27B1 mutation in resource limited countries.

OBJECTIVES: Vitamin D dependent rickets type 1A (VDDR1A) is a rare autosomal recessive condition due to inactivating mutation of CYP27B1. It mimics clinically, biochemically and rediologically to nutritional and hypophosphatemic rickets. In developing countries like Pakistan, VDDR1A is often misdiagnosed as nutritional rickets or hypophosphatemic rickets due lack of free access to 1,25 (OH) 2 D level and genetic testing. This study was aimed to determine the clinical spectrum and diagnostic challenges of VDDR1A due to CYP27B1 mutation in developing countries. METHODS: Retrospective review of all cases of VDDR1A due to CYP27B1 mutation over a period of two years presenting in the Pediatric Endocrine clinic of Hameed Latif Hospital, Lahore, Pakistan. RESULTS: Six cases of VDDR1A (4 males) were identified. Mean age of clinical manifestation was 14 (9-24) months. Mean age of presentation to endocrine department was 5.5 (1.5-11.8) years. Growth failure and bony deformities were the most common presentation (n=6), followed by repeated diarrheas and abdominal distension (n=3) and recurrent fractures (n=1). All cases shared same biochemical profile of low/normal calcium, hypophosphatemia, raised alkaline phosphatase, raised PTH, normal/high 25(OH)D and tubular reabsorption of phosphate (TRP) <85%. Patients treated with calcitriol showed rapid healing as compared to those treated with 1-alfacalcidol. CONCLUSIONS: We should have a high index of suspicion of VDDR1A in rickets not responding to cholecalciferol therapy.

Management challenges of Rabson Mendenhall syndrome in a resource limited country: a case report.

OBJECTIVES: Rabson Mendenhall syndrome  (RMS) is a rare form of insulin resistance syndrome caused by insulin receptor mutation. In term of severity, it lies at an intermediate point on spectrum of insulin resistance with Donohue syndrome flanking the severe and Type A insulin resistance at the mild end. We are reporting a 3.5-month-old boy with RMS along with its management challenges in a resource limited country. CASE PRESENTATION: An infant presented at 3.5-month of an age with failure to thrive and fluctuating blood glucose level (hyperglycaemia and hypoglycaemia) along with clinical features of insulin resistance. He was found to have raised HbA1C, high insulin and C peptide level and a homozygous mutation in INSR gene c.1049C>T, (p.Ser350 Leu) confirming the diagnosis of RMS. He was managed with long-acting insulin (Detemir) along with frequent feeding. CONCLUSIONS: RMS in resource limited countries could be managed with frequent feeding along with insulin. Early diagnosis and management can improve long term outcome.

Bi-allelic loss-of-function variants in TMEM147 cause moderate to profound intellectual disability with facial dysmorphism and pseudo-Pelger-Huët anomaly.

The transmembrane protein TMEM147 has a dual function: first at the nuclear envelope, where it anchors lamin B receptor (LBR) to the inner membrane, and second at the endoplasmic reticulum (ER), where it facilitates the translation of nascent polypeptides within the ribosome-bound TMCO1 translocon complex. Through international data sharing, we identified 23 individuals from 15 unrelated families with bi-allelic TMEM147 loss-of-function variants, including splice-site, nonsense, frameshift, and missense variants. These affected children displayed congruent clinical features including coarse facies, developmental delay, intellectual disability, and behavioral problems. In silico structural analyses predicted disruptive consequences of the identified amino acid substitutions on translocon complex assembly and/or function, and in vitro analyses documented accelerated protein degradation via the autophagy-lysosomal-mediated pathway. Furthermore, TMEM147-deficient cells showed CKAP4 (CLIMP-63) and RTN4 (NOGO) upregulation with a concomitant reorientation of the ER, which was also witnessed in primary fibroblast cell culture. LBR mislocalization and nuclear segmentation was observed in primary fibroblast cells. Abnormal nuclear segmentation and chromatin compaction were also observed in approximately 20% of neutrophils, indicating the presence of a pseudo-Pelger-Huët anomaly. Finally, co-expression analysis revealed significant correlation with neurodevelopmental genes in the brain, further supporting a role of TMEM147 in neurodevelopment. Our findings provide clinical, genetic, and functional evidence that bi-allelic loss-of-function variants in TMEM147 cause syndromic intellectual disability due to ER-translocon and nuclear organization dysfunction.

Loss of FOCAD, operating via the SKI messenger RNA surveillance pathway, causes a pediatric syndrome with liver cirrhosis.

Cirrhosis is usually a late-onset and life-threatening disease characterized by fibrotic scarring and inflammation that disrupts liver architecture and function. While it is typically the result of alcoholism or hepatitis viral infection in adults, its etiology in infants is much less understood. In this study, we report 14 children from ten unrelated families presenting with a syndromic form of pediatric liver cirrhosis. By genome/exome sequencing, we found recessive variants in FOCAD segregating with the disease. Zebrafish lacking focad phenocopied the human disease, revealing a signature of altered messenger RNA (mRNA) degradation processes in the liver. Using patient's primary cells and CRISPR-Cas9-mediated inactivation in human hepatic cell lines, we found that FOCAD deficiency compromises the SKI mRNA surveillance pathway by reducing the levels of the RNA helicase SKIC2 and its cofactor SKIC3. FOCAD knockout hepatocytes exhibited lowered albumin expression and signs of persistent injury accompanied by CCL2 overproduction. Our results reveal the importance of FOCAD in maintaining liver homeostasis and disclose a possible therapeutic intervention point via inhibition of the CCL2/CCR2 signaling axis.

An integrated multiomic approach as an excellent tool for the diagnosis of metabolic diseases: our first 3720 patients.

To present our experience using a multiomic approach, which integrates genetic and biochemical testing as a first-line diagnostic tool for patients with inherited metabolic disorders (IMDs). A cohort of 3720 patients from 62 countries was tested using a panel including 206 genes with single nucleotide and copy number variant (SNV/CNV) detection, followed by semi-automatic variant filtering and reflex biochemical testing (25 assays). In 1389 patients (37%), a genetic diagnosis was achieved. Within this cohort, the highest diagnostic yield was obtained for patients from Asia (57.5%, mainly from Pakistan). Overall, 701 pathogenic/likely pathogenic unique SNVs and 40 CNVs were identified. In 620 patients, the result of the biochemical tests guided variant classification and reporting. Top five diagnosed diseases were: Gaucher disease, Niemann-Pick disease type A/B, phenylketonuria, mucopolysaccharidosis type I, and Wilson disease. We show that integrated genetic and biochemical testing facilitated the decision on clinical relevance of the variants and led to a high diagnostic yield (37%), which is comparable to exome/genome sequencing. More importantly, up to 43% of these patients (n = 610) could benefit from medical treatments (e.g., enzyme replacement therapy). This multiomic approach constitutes a unique and highly effective tool for the genetic diagnosis of IMDs.

Kleefstra Syndrome with Severe Sensory Neural Deafness and De Novo Novel Mutation.

Kleefstra syndrome is a rare inherited neuro-developmental condition characterised by facial dysmorphism, microcephaly, hypotonia, developmental delay, and intellectual disability. It is a rare syndrome; and less than 100 cases with different genetic mutations are reported so far. We report an eight-month baby boy with Kleefstra syndrome type 2 due to a novel de novo pathogenic mutation in the KMT2C (Lysine methyltransferase 2C) gene. Key Words: Kleefstra syndrome, KMT2C gene, Neurodevelopmental disorder, Deafness.

Tricho-Hepato-Eenteric Syndrome: Same Genotype but Different Phenotypes in Two Pakistani Children.

Tricho-hepato-enteric syndrome (THES) is characterised by infantile diarrhea with characteristic facies, trichorrhexis nodosa and hepatic involvement. The underlying genetic mutation is in tetratricopeptide repeat domain 37 (TTC37) gene. It is a very rare syndrome and only 44 cases have been reported so far in the medical literature. We recently diagnosed two children with THES on genetic analysis, who had same genotype but different phenotypes. Using these cases as a precedent, we reviewed what is known about this rare syndrome, as well as the novelties in our cases and treatment options. Key Words: Chronic diarrhea, Liver disease, Genetic mutation, TTC37.

A disorder clinically resembling cystic fibrosis caused by biallelic variants in the AGR2 gene.

PURPOSE: We sought to describe a disorder clinically mimicking cystic fibrosis (CF) and to elucidate its genetic cause. METHODS: Exome/genome sequencing and human phenotype ontology data of nearly 40 000 patients from our Bio/Databank were analysed. RNA sequencing of samples from the nasal mucosa from patients, carriers and controls followed by transcriptome analysis was performed. RESULTS: We identified 13 patients from 9 families with a CF-like phenotype consisting of recurrent lower respiratory infections (13/13), failure to thrive (13/13) and chronic diarrhoea (8/13), with high morbidity and mortality. All patients had biallelic variants in AGR2, (1) two splice-site variants, (2) gene deletion and (3) three missense variants. We confirmed aberrant AGR2 transcripts caused by an intronic variant and complete absence of AGR2 transcripts caused by the large gene deletion, resulting in loss of function (LoF). Furthermore, transcriptome analysis identified significant downregulation of components of the mucociliary machinery (intraciliary transport, cilium organisation), as well as upregulation of immune processes. CONCLUSION: We describe a previously unrecognised autosomal recessive disorder caused by AGR2 variants. AGR2-related disease should be considered as a differential diagnosis in patients presenting a CF-like phenotype. This has implications for the molecular diagnosis and management of these patients. AGR2 LoF is likely the disease mechanism, with consequent impairment of the mucociliary defence machinery. Future studies should aim to establish a better understanding of the disease pathophysiology and to identify potential drug targets.

Spectrum of Clinical Presentation of Celiac Disease in Pediatric Population.

Background Classic form of celiac disease (CCD) presents with diarrhea and is traditionally taught as malabsorption syndrome. This form of CD is diagnosed with ease but non-classical form presenting without diarrhea is often missed and heavily underdiagnosed. Objective To determine the clinical spectrum of patients with CD. Methods This study was conducted in the Department of Gastroenterology & Hepatology at the Children's Hospital, Lahore. Confirmed CD children according to NASPGHAN (North American Society of Pediatric Gastroenterology, Hepatology & Nutrition) criteria were enrolled in this study from June to September, 2020. Initial positivity followed by small bowel biopsy with Modified Marsh 2 and above is considered consistent with the diagnosis of CD. Results A total of 90 patients were selected according to NASPGHAN criteria, 77 (85.6%) patients had CCD whereas 13 (14.4%) patients had non-classical CD (NCCD). The mean ± SD age at diagnosis of CCD was 2.6 ± 2.3 years whereas mean ± SD in NCCD was 9 ± 1.8 years. Females clearly predominate in our cohort in general. Chronic diarrhea followed by failure to thrive (85%) were the most common symptoms in CCD whereas short stature (69%) was the most frequent feature in NCCD. Among CD patients, tissue transglutaminase-​immunoglobulin A (TTG-IgA) titre was significantly high (>10 times) in 80% of CD patients and the rest had positivity but not up to 10 times. There was no significant difference in titre of anti-TTG between CCD and NCCD. Conclusion Classical CD is still the most common in developing countries like Pakistan. High index of suspicion of CD should be maintained for patients who present with short stature, recurrent abdominal pain and refractory anemia.

Combining exome/genome sequencing with data repository analysis reveals novel gene-disease associations for a wide range of genetic disorders.

PURPOSE: Within this study, we aimed to discover novel gene-disease associations in patients with no genetic diagnosis after exome/genome sequencing (ES/GS). METHODS: We followed two approaches: (1) a patient-centered approach, which after routine diagnostic analysis systematically interrogates variants in genes not yet associated to human diseases; and (2) a gene variant centered approach. For the latter, we focused on de novo variants in patients that presented with neurodevelopmental delay (NDD) and/or intellectual disability (ID), which are the most common reasons for genetic testing referrals. Gene-disease association was assessed using our data repository that combines ES/GS data and Human Phenotype Ontology terms from over 33,000 patients. RESULTS: We propose six novel gene-disease associations based on 38 patients with variants in the BLOC1S1, IPO8, MMP15, PLK1, RAP1GDS1, and ZNF699 genes. Furthermore, our results support causality of 31 additional candidate genes that had little published evidence and no registered OMIM phenotype (56 patients). The phenotypes included syndromic/nonsyndromic NDD/ID, oral-facial-digital syndrome, cardiomyopathies, malformation syndrome, short stature, skeletal dysplasia, and ciliary dyskinesia. CONCLUSION: Our results demonstrate the value of data repositories which combine clinical and genetic data for discovering and confirming gene-disease associations. Genetic laboratories should be encouraged to pursue such analyses for the benefit of undiagnosed patients and their families.

Indicators Of Hepatopulmonary Syndrome In Patients With Portal Hypertension. Its Various Aetiologies, Clinical Presentations And Outcome.

BACKGROUND: Hepatopulmonary syndrome is severe pulmonary vascular complication of chronic liver disease requiring liver transplant. This study was conducted to evaluate different indicators of HPS in patients with portal hypertension, its varied aetiologies, clinical features & outcome. METHODS: Hospital based descriptive study, 203 patients were enrolled, divided in to 2 groups positive and negative on the basis of presence or absence of HPS as per diagnostic criteria. RESULTS: It included 203 patients with portal Hypertension of varied aetiologies. Age range was 8.76±3.69 years. 54.7% were male & 45.3% female. Commonest diagnosis for portal hypertension was portal vein thrombosis in 48 (23.6%) while Least common was biliary atresia seen in 6 (3%) of cases. Fifteen patients were included in Positive group and 188 in negative group. Clinical & laboratory parameters in order of frequency in positive group were hypoxia & cyanosis in 100% & 93.3% followed by dyspnoea & grade 4 clubbing in 86.6% patients (p<0.001). Child scoring was also done in all patients. In negative group 7 (3.7%) had dyspnoea, I (0.53%) had grade 4 clubbing while none showed evidence of hypoxia or cyanosis (p<0.001). Three patients underwent successful liver transplant. One patient of biliary atresia & another of CHF expired. CONCLUSIONS: In All children with CLD and/or PHT with unexplained dyspnoea, cyanosis and grade 4 clubbing, HPS should be suspected. It is an indication for early LT even in absence of liver failure.

Very early onset inflammatory bowel disease: Spectrum of clinical presentation, diagnostic tools and outcome in children.

OBJECTIVE: To explore the spectrum of presentation, underlying monogenetic defects and outcome in very early onset inflammatory bowel disease (VEO-IBD). METHOD: The prospective, observational study was conducted at the Children's Hospital, Lahore, Pakistan, from January 2017 to December 2018, and comprised children developing features of inflammatory bowel disease aged <6 years. Data included demography, clinical presentation, diagnostic tools and outcome. Data was analysed using SPSS 21. RESULTS: Of the 60 children with relevant symptoms, 26(43.3%) were diagnosed as having very early onset inflammatory bowel disease. Of them, 13(50%) had underlying monogenic defect, and 16(61.5%) had ulcerative colitis. There were 22(84.6%) males with median age of 1.5(11) months in monogenic inflammatory bowel disease versus 24(43) months for non-monogenic inflammatory bowel disease (p<0.05). In the monogenic group, isolated rectal bleeding was the major presentation 13(100%) versus non-monogenic who presented mainly with failure to thrive 13(100%). Upper and lower endoscopies with histopathology had good diagnostic yield and inflammatory infiltrates on the biopsied tissues were the major findings. Mutations detected among the subjects were XIAP, PRKDC, PIK3CD, RAG-1, LRBA, DOCK8, TTC7, MEFV and EPCAM. Mortality was significantly higher in the monogenic group 7(54%) than in the non-monogenic group 2(15%) (p<0.05). CONCLUSIONS: Very early onset inflammatory bowel disease should be suspected when conventional management fails to rectify common disease mimickers. Testing for underlying immunological defect and genetic mutation would be helpful for managing these rare disorders.

Genomic testing in 1019 individuals from 349 Pakistani families results in high diagnostic yield and clinical utility.

We implemented a collaborative diagnostic program in Lahore (Pakistan) aiming to establish the genetic diagnosis, and to asses diagnostic yield and clinical impact in patients with suspected genetic diseases. Local physicians ascertained pediatric patients who had no previous access to genetic testing. More than 1586 genetic tests were performed in 1019 individuals (349 index cases, 670 relatives). Most frequently performed tests were exome/genome sequencing (ES/GS, 284/78 index cases) and specific gene panels (55 index cases). In 61.3% of the patients (n = 214) a genetic diagnosis was established based on pathogenic and likely pathogenic variants. Diagnostic yield was higher in consanguineous families (60.1 vs. 39.5%). In 27 patients, genetic diagnosis relied on additional biochemical testing, allowing rapid assessment of the functional effect of the variants. Remarkably, the genetic diagnosis had a direct impact on clinical management. Most relevant consequences were therapy related such as initiation of the appropriated treatment in a timely manner in 51.9% of the patients (n = 111). Finally, we report 12 candidate genes among 66 cases with no genetic diagnosis. Importantly, three of these genes were validated as 'diagnostic' genes given the strong evidence supporting causality derived from our data repository (CAP2-dilated cardiomyopathy, ITFG2-intellectual disability and USP53-liver cholestasis). The high diagnostic yield, clinical impact, and research findings demonstrate the utility of genomic testing, especially when used as first-line genetic test. For patients with suspected genetic diseases from resource-limited regions, ES can be considered as the test of choice to achieve genetic diagnosis.

Variability of clinical and biochemical phenotype in liver phosphorylase kinase deficiency with variants in the phosphorylase kinase (PHKG2) gene.

Background PHKG2-related liver phosphorylase kinase deficiency is inherited in autosomal recessive pattern and is a rare type of liver glycogenosis. We demonstrated the clinical presentation and genetic determinants involved in children with PHKG2- related liver phosphorylase kinase deficiency. Methodology Ten Pakistani children with liver phosphorylase kinase from seven different families, were enrolled over a period of 18 months. All regions of the PHKG2 gene spanning exons and splicing sites were evaluated through targeted exome sequencing. Variants were analyzed using different bioinformatics tools. Novel variants were reconfirmed by direct sequencing. Results Seven different variants were identified in PHKG2 gene including five novel variants: three stop codons (c.226C>T [p.R76*], c.454C>T [p.R152*] and c.958C>T [p.R320*]), one missense variant c.107C>T (p.S36F) and one splice site variant (c.557-3C>G). All five novel variants were predicted to be damaging by in Silico analysis. The variants are being transmitted through recessive pattern of inheritance except one family (two siblings) has compound heterozygotes. Laboratory data revealed elevated transaminases and triglycerides, normal creatinine phosphokinase and uric acid levels but with glycogen loaded hepatocytes on liver histology. Conclusion PHKG2 related liver phosphorylase kinase deficiency can mimic both liver glycogenosis type I (glucose-6-phosphatase deficiency) & III(amylo-1,6 glucosidase) and characterized by early childhood onset of hepatomegaly, growth restriction, elevated liver enzymes and triglycerides. Molecular analysis would be helpful in accurate diagnosis and proper treatment. The symptoms and biochemical abnormalities in liver glycogenosis due phosphorylase kinase deficiency tend to improve with proper dietary restrictions but need to be monitored for long-term complications such as liver fibrosis and cirrhosis.