Inborn Errors of Ketogenesis: Novel Variants, Clinical Presentation, and Follow-Up in a Series of Four Patients.

Inborn errors of ketogenesis are rare disorders that result in acute and fulminant decompensation during lipolytic stress, particularly in infants and children. These include mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase (HMGCS) deficiency and HMG-CoA lyase (HMGCL) deficiency. In this series, we describe the clinical, biochemical, and molecular profiles of four patients along with dietary interventions and their outcomes on a long-term follow-up. Two patients each of HMGCS and HMGCL deficiency were evaluated with clinical history, biochemical investigations, including tandem mass spectrometry (TMS) and urine gas chromatography-mass spectrometry (GCMS). Molecular analysis was performed by whole-exome sequencing, as well as exon array validated by long-range polymerase chain reaction. All individuals were diagnosed with acute metabolic decompensation in the early infancy period except one with HMGCL deficiency who had the first presentation at 5 years of age. Central nervous system manifestations, severe metabolic acidosis, hyperammonemia, hypoglycemia with a normal lactate, and absence of urinary ketones were observed in all the affected individuals. The disorder was life-threatening in three individuals and one succumbed to the illness. TMS was nonspecific and urine GCMS revealed dicarboxylic aciduria in HMGCS deficiency. Both the patients with HMGCL deficiency demonstrated elevated 3 hydroxyisovaleryl carnitine levels in TMS and metabolites of leucine degradation in urine GCMS. We identified five novel variants that included a large deletion involving exon 2 in HMGCL gene. There was no evidence of long-term neurological sequelae in the living individuals. Diet with moderation of fat intake was followed in two individuals with HMGCS deficiency. Low leucine and protein diet with moderation of fat intake was followed in the individual with HMGCL deficiency. All affected individuals are thriving well with no further major metabolic decompensation.

Fetal Ultrasound Segmentation and Measurements Using Appearance and Shape Prior Based Density Regression with Deep CNN and Robust Ellipse Fitting.

Accurately segmenting the structure of the fetal head (FH) and performing biometry measurements, including head circumference (HC) estimation, stands as a vital requirement for addressing abnormal fetal growth during pregnancy under the expertise of experienced radiologists using ultrasound (US) images. However, accurate segmentation and measurement is a challenging task due to image artifact, incomplete ellipse fitting, and fluctuations due to FH dimensions over different trimesters. Also, it is highly time-consuming due to the absence of specialized features, which leads to low segmentation accuracy. To address these challenging tasks, we propose an automatic density regression approach to incorporate appearance and shape priors into the deep learning-based network model (DR-ASPnet) with robust ellipse fitting using fetal US images. Initially, we employed multiple pre-processing steps to remove unwanted distortions, variable fluctuations, and a clear view of significant features from the US images. Then some form of augmentation operation is applied to increase the diversity of the dataset. Next, we proposed the hierarchical density regression deep convolutional neural network (HDR-DCNN) model, which involves three network models to determine the complex location of FH for accurate segmentation during the training and testing processes. Then, we used post-processing operations using contrast enhancement filtering with a morphological operation model to smooth the region and remove unnecessary artifacts from the segmentation results. After post-processing, we applied the smoothed segmented result to the robust ellipse fitting-based least square (REFLS) method for HC estimation. Experimental results of the DR-ASPnet model obtain 98.86% dice similarity coefficient (DSC) as segmentation accuracy, and it also obtains 1.67 mm absolute distance (AD) as measurement accuracy compared to other state-of-the-art methods. Finally, we achieved a 0.99 correlation coefficient (CC) in estimating the measured and predicted HC values on the HC18 dataset.

Retrospective diagnosis by parental testing in the next generation sequencing era and utility of reanalysis of exome data.

OBJECTIVE: Genetic diseases are an important cause of neonatal and childhood mortality. For couples with a history of demise of previous children, screening for carrier status can be done by exome sequencing (ES) of the parents. Our aim was to describe the clinical utility of "targeted parental ES" in such couples and to assess the utility of reanalysis of parental ES data. METHOD: We analyzed previous records, including ES reports, of 52 families with demise of previous offspring with a suspected genetic disorder. We also retrieved and reanalyzed raw data of parental ES in FASTQ format from the testing lab. RESULTS: A potential diagnosis was obtained in 30/52 (57.7%) of couples. We found 38/70 (54.3%) novel variants in this cohort. Shared carrier status for more than one autosomal or X-linked recessive disorder was identified in 18% of couples. Reanalysis of raw data resulted in a reclassification of variants in 15% of cases. CONCLUSION: Targeted parental ES can be helpful for families with demise of previous offspring with a suspected genetic disorder.

Neurodegeneration with brain iron accumulation: a case series highlighting phenotypic and genotypic diversity in 20 Indian families.

Neurodegeneration with brain iron accumulation (NBIA) is an umbrella term encompassing various inherited neurological disorders characterised by abnormal iron accumulation in basal ganglia. We aimed to study the clinical, radiological and molecular spectrum of disorders with NBIA. All molecular-proven cases of NBIA presented in the last 5 years at 2 tertiary care genetic centres were compiled. Demographic details and clinical and neuroimaging findings were collated. We describe 27 individuals from 20 unrelated Indian families with causative variants in 5 NBIA-associated genes. PLA2G6-associated neurodegeneration (PLAN) was the most common, observed in 13 individuals from 9 families. They mainly presented in infancy with neuroregression and hypotonia. A recurrent pathogenic variant in COASY was observed in two neonates with prenatal-onset severe neurodegeneration. Pathogenic bi-allelic variants in PANK2, FA2H and C19ORF12 genes were observed in the rest, and these individuals presented in late childhood and adolescence with gait abnormalities and extrapyramidal symptoms. No intrafamilial and interfamilial variability were observed. Iron deposition on neuroimaging was seen in only 6/17 (35.3%) patients. A total of 22 causative variants across 5 genes were detected including a multiexonic duplication in PLA2G6. The variants c.1799G > A and c.2370 T > G in PLA2G6 were observed in three unrelated families. In silico assessments of 8 amongst 9 novel variants were also performed. We present a comprehensive compilation of the phenotypic and genotypic spectrum of various subtypes of NBIA from the Indian subcontinent. Clinical presentation of NBIAs is varied and not restricted to extrapyramidal symptoms or iron accumulation on neuroimaging.

Integrated Management Strategies for Epidermolysis Bullosa: Current Insights.

Epidermolysis bullosa (EB) is a group of rare genodermatoses that is characterized by skin fragility resulting from minor trauma. There are four major subtypes, namely, EB simplex, junctional EB, dystrophic EB and Kindler EB, depending upon the localization of defective protein and resulting plane of blister formation. The phenotype is heterogeneous in terms of severity and majority of them present at birth or neonatal period. Currently, the treatment is mainly supportive and requires multidisciplinary care. The complex molecular pathology creates difficulty in discovering a unified curative treatment approach. But with arduous efforts, significant progress has been made in the development of treatment strategies in the last decade. The management strategies range from targeting the underlying causative factor to symptom-relieving approaches, and include gene, mRNA, protein, cell and combination therapies. In this review, we enumerate the promising approaches that are currently under various stages of investigation to provide effective treatment for patients with EB.

Deciphering the molecular landscape of microcephaly in 87 Indian families by exome sequencing.

Microcephaly is a frequent feature of neurodevelopmental disorders (NDDs). Our study presents the heterogeneous spectrum of genetic disorders in patients with microcephaly either in isolated form or in association with other neurological and extra-neural abnormalities. We present data of 91 patients from 87 unrelated families referred to our clinic during 2016-2020 and provide a comprehensive clinical and genetic landscape in the studied cohort. Molecular diagnosis using exome sequencing was made in 45 families giving a yield of 51.7%. In 9 additional families probable causative variants were detected. We identified disease causing variations in 49 genes that are involved in different functional pathways Among these, 36 had an autosomal recessive pattern, 8 had an autosomal dominant pattern (all inherited de novo), and 5 had an X-linked pattern. In 41 probands where sequence variations in autosomal recessive genes were identified 31 were homozygotes (including 16 from non-consanguineous families). The study added 28 novel pathogenic/likely pathogenic variations. The study also calls attention to phenotypic variability and expansion in spectrum as well as uncovers genes where microcephaly is not reported previously or is a rare finding. We here report phenotypes associated with the genes for ultra-rare NDDs with microcephaly namely ATRIP, MINPP1, PNPLA8, AIMP2, ANKLE2, NCAPD2 and TRIT1.

Meckel Gruber and Joubert Syndrome Diagnosed Prenatally: Allelism between the Two Ciliopathies, Complexities of Mutation Types and Digenic Inheritance.

Background: Antenatally detected occipital encephalocele and polycystic kidneys are a common presentation of ciliopathies like Joubert syndrome and Meckel Gruber syndrome which have considerable genetic and phenotypic overlap. Case reports: We describe 3 cases of antenatally diagnosed occipital encephalocele and enlarged kidneys with fetal autopsy, histopathology & exome sequencing results. A novel nonsense variant in the CEP290 gene was reported in first case (Meckel syndrome). The second case shows the importance of fetal exome where the parents were carriers for 2 ciliopathy genes (TMEM138 & SDCCAG8). Diagnosis in this case was confirmed by fetal exome sequencing (Joubert syndrome). Multiexon deletion in TMEM67 and KIF14 present in trans was identified in the third case (Meckel syndrome), likely resulting in digenic inheritance. Conclusion: We report 2 cases of Meckel syndrome with a novel variant and multiexon deletion, and 1 case of Joubert syndrome which depicts the limitations of preconceptional carrier screening in ciliopathies due to overlapping phenotypes.