Case Report: Infant With Congenital Adrenal Hyperplasia and 47,XXY

Congenital adrenal hyperplasia is a group of autosomal recessive disorders in which enzymes in the cortisol biosynthesis pathways are disrupted by gene mutations. The most common form of congenital adrenal hyperplasia, caused by 21-hydroxylase deficiency, is characterized by decreased cortisol and aldosterone synthesis and excessive androgen production. Adult height is often compromised in affected patients. Intellectual capability remains intact in patients with congenital adrenal hyperplasia caused by 21-hydroxylase deficiency, based on previous studies. 47,XXY (KS) is a sex chromosomal aneuploidy that manifests with hypergonadotropic hypogonadism, tall stature, and variable intellectual and behavioral dysfunction. This clinical report describes an infant with 21-hydroxylase deficiency congenital adrenal hyperplasia and 47,XXY. The results of his neurodevelopmental, endocrine, neurological, and physical therapy evaluations during his first 22 months are included and were normal. This is the first published case investigating the neurodevelopmental profile of a patient with the combination of these two genetic disorders.

A Case of Wilson’s Disease Presenting with Persistant Hemolysis

Wilson’s disease is one the rare autosomal recessive disorders of copper metabolism due to mutation in ATP7B gene located in chromosome 13. The mutations of this gene cause accumulation of copper in different tissues such as brain, liver, and eyes. The clinical presentation usually reflects this tissue distribution and varies from asymptomatic patients to those with hepatic or neuro-psychiatric manifestations. Here, we report an interesting case of Wilson’s disease which presented with mild persistent hemolysis leading to pre hepatic and post hepatic jaundice. He also had hepatocellular jaundice due to liver injury.

Co-occurrence of sickle cell disease and oculocutaneous albinism in a Congolese patient: a case report

Background Sickle cell disease and oculocutaneous albinism are rare autosomal recessive disorders both related to mutations on chromosome 11. The diagnosis of patients suffering from both pathologies is necessary to enable dedicated monitoring of any complications at the ophthalmic and skin level. However, few cases are described in the literature. Case presentation A 14-month-old Congolese male child affected by oculocutaneous albinism, presented with pallor and jaundice. Blood indices revealed severe hemolytic anemia, which led to the diagnosis of sickle cell disease. The patient received a blood transfusion and close follow-up. Conclusions The co-inheritance of sickle cell disease and oculocutaneous albinism is a reality in the Democratic Republic of Congo, although it is rarely described. Given the current state of our knowledge, specific surveillance, specifically regarding cutaneous and ophthalmological complications, should be offered in this particular population. To enable this dedicated follow-up, sensitization to screening for sickle cell anemia in albino individuals should be carried out.

L-Arginine Ameliorates Defective Autophagy in GM2 Gangliosidoses by mTOR Modulation

Aims: Tay–Sachs and Sandhoff diseases (GM2 gangliosidosis) are autosomal recessive disorders of lysosomal function that cause progressive neurodegeneration in infants and young children. Impaired hydrolysis catalysed by β-hexosaminidase A (HexA) leads to the accumulation of GM2 ganglioside in neuronal lysosomes. Despite the storage phenotype, the role of autophagy and its regulation by mTOR has yet to be explored in the neuropathogenesis. Accordingly, we investigated the effects on autophagy and lysosomal integrity using skin fibroblasts obtained from patients with Tay–Sachs and Sandhoff diseases. Results: Pathological autophagosomes with impaired autophagic flux, an abnormality confirmed by electron microscopy and biochemical studies revealing the accelerated release of mature cathepsins and HexA into the cytosol, indicating increased lysosomal permeability. GM2 fibroblasts showed diminished mTOR signalling with reduced basal mTOR activity. Accordingly, provision of a positive nutrient signal by L-arginine supplementation partially restored mTOR activity and ameliorated the cytopathological abnormalities. Innovation: Our data provide a novel molecular mechanism underlying GM2 gangliosidosis. Impaired autophagy caused by insufficient lysosomal function might represent a new therapeutic target for these diseases. Conclusions: We contend that the expression of autophagy/lysosome/mTOR-associated molecules may prove useful peripheral biomarkers for facile monitoring of treatment of GM2 gangliosidosis and neurodegenerative disorders that affect the lysosomal function and disrupt autophagy.

The contribution of common regulatory and protein-coding TYR variants in the genetic architecture of albinism

Genetic diseases have been historically segregated into rare Mendelian and common complex conditions. Large-scale studies using genome sequencing are eroding this distinction and are gradually unmasking the underlying complexity of human traits. We studied a cohort of 1,313 individuals with albinism aiming to gain insights into the genetic architecture of rare, autosomal recessive disorders. We investigated the contribution of regulatory and protein-coding variants at the common and rare ends of the allele-frequency spectrum. We focused on TYR, the gene encoding tyrosinase, and found that a promoter variant, TYR: c.-301C>T [rs4547091], modulates the penetrance of a prevalent, disease-associated missense change, TYR: c.1205G>A [rs1126809]. We also found that homozygosity for a haplotype formed by three common, functional variants, TYR: c.[-301C;575C>A;1205G>A], confers a high risk of albinism (OR>77) and is associated with reduced vision in UK Biobank participants. Finally, we report how the combined analysis of rare and common variants increases diagnostic yield and informs genetic counselling in families with albinism.

Systematic identification of intron retention associated variants from massive publicly available transcriptome sequencing data

Many disease-associated genomic variants disrupt gene function through abnormal splicing. With the advancement of genomic medicine, identifying disease-associated splicing associated variants has become more important than ever. Most bioinformatics approaches to detect splicing associated variants require both genome and transcriptomic data. However, there are not many datasets where both of them are available. In this study, we developed a methodology to detect genomic variants that cause splicing changes (more specifically, intron retention), using transcriptome sequencing data alone. After demonstrating its high sensitivity and precision, we have applied it to 230,988 transcriptome sequencing data from the publicly available repository and identified 27,937 intron retention associated variants (IRAVs). In addition, by exploring positional relationships with variants registered in existing disease databases, we extracted 3,077 putative disease-associated IRAVs, which range from cancer drivers to variants linked with autosomal recessive disorders. The new in-silico screening framework proposed here provides a foundation for a platform that can automatically acquire medical knowledge making the most of massively accumulated publicly available sequencing data. Collections of IRAVs identified in this study are available through IRAVDB (https://iravdb.io/).

Unmet needs and evolving treatment for limb girdle muscular dystrophies

Limb-girdle muscular dystrophies (LGMDs) represent a major group of muscle disorders. Treatment is sorely needed and currently expanding based on safety and efficacy adopting principles of single-dosing gene therapy for monogenic autosomal recessive disorders. Gene therapy has made in-roads for LGMD and this review describes progress that has been achieved for these conditions. This review first provides a background on the definition and classification of LGMDs. The major effort focuses on progress in LGMD gene therapy, from experimental studies to clinical trials. The disorders discussed include the LGMDs where the most work has been done including calpainopathies (LGMD2A/R1), dysferlinopathies (LGMD2B/R2) and sarcoglycanopathies (LGMD2C/R5, LGMD2D/R3, LGMD2E/R4). Early success in clinical trials provides a template to move the field forward and potentially apply emerging technology like CRISPR/Cas9 that may enhance the scope and efficacy of gene therapy applied to patient care.

The prevalence, genetic complexity and population-specific founder effects of human autosomal recessive disorders

Autosomal recessive (AR) disorders pose a significant burden for public health. However, despite their clinical importance, epidemiology and molecular genetics of many AR diseases remain poorly characterized. Here, we analyzed the genetic variability of 508 genes associated with AR disorders based on sequencing data from 141,456 individuals across seven ethnogeographic groups by integrating variants with documented pathogenicity from ClinVar, with stringent functionality predictions for variants with unknown pathogenicity. We first validated our model using 85 diseases for which population-specific prevalence data were available and found that our estimates strongly correlated with the respective clinically observed disease frequencies (r = 0.68; p < 0.0001). We found striking differences in population-specific disease prevalence with 101 AR diseases (27%) being limited to specific populations, while an additional 305 diseases (68%) differed more than tenfold across major ethnogeographic groups. Furthermore, by analyzing genetic AR disease complexity, we confirm founder effects for cystic fibrosis and Stargardt disease, and provide strong evidences for >25 additional population-specific founder mutations. The presented analyses reveal the molecular genetics of AR diseases with unprecedented resolution and provide insights into epidemiology, complexity, and population-specific founder effects. These data can serve as a powerful resource for clinical geneticists to inform population-adjusted genetic screening programs, particularly in otherwise understudied ethnogeographic groups.