Congenital Disorders

This chapter is devoted to specific diseases presenting usually in early infancy or childhood as a result of disruption in the normal development of the cornea and its associated structures. These disorders may develop due to one or a combination of various genetic, infectious, inflammatory, toxic, metabolic, traumatic, or mechanical processes and may occur at any time during tissue induction, differentiation, and maturation. Adjacent structures (anterior chamber angle, iris, and lens) can be impacted too. Congenital limbal stem cell deficiency is usually associated with aniridia and ectodermal dysplasia. Aniridia can occur in a sporadic or familial form. The familial inheritance pattern of aniridia is predominantly autosomal dominant. The aniridia phenotype varies depending on the mutation present. Interesting ocular congenital disorders associated with Neurofibromatosis, Axenfeld-Rieger syndrome, Icthyosis are shown in this chapter. It presents a rare case of porphyria-associated sclerocorneal melting with before and after treatment photos.

Loss of Activity-Induced Mitochondrial ATP Production Underlies the Synaptic Defects in a Drosophila model of ALS

Mutations in the gene encoding VAPB (vesicle-associated membrane protein B) cause a familial form of Amyotrophic Lateral Sclerosis (ALS). Expression of an ALS-related variant of vapb (vapbP58S) in Drosophila motor neurons results in morphological changes at the larval neuromuscular junction (NMJ) characterized by the appearance of fewer, but larger, presynaptic boutons. Although diminished microtubule stability is known to underlie these morphological changes, a mechanism for the loss of presynaptic microtubules has been lacking. Here, we demonstrate the suppression of vapbP58S-induced changes in NMJ morphology by either the loss of ER Ca2+ release channels or the inhibition Ca2+/calmodulin (CaM)-activated kinase II (CaMKII). These data suggest a model in which decreased stability of presynaptic microtubules at vapbP58S NMJs result from hyperactivation of CaMKII due to elevated cytosolic [Ca2+]. We attribute the Ca2+ dyshomeostasis to delayed extrusion of cytosolic Ca2+ stemming from a paucity of activity-induced mitochondrial ATP production coupled with elevated rates of ATP consumption. Taken together, our data point to bioenergetic dysfunction as the root cause for the synaptic defects in vapbP58S-expressing Drosophila motor neurons.

ADULT SECONDARY HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS – A CASE SERIES

Hemophagocytic lymphohistiocytosis is a hyper-inammatory condition that is either Familial (Primary) or Secondary to autoimmune diseases , infection, malignancy or other triggers.It is a cytokine storm syndrome where there inefcient antigen removal that leads to sustained cytokine release.It is a rare phenomenon occuring in adults that has got a specic trigger which is less documented and have a good response to steroids where as Familial form is a childhood disease due to genetic defects, both of which are life threatening and may need Allogenic bone marrow transplant. Macrophage activation syndrome is also a subtype of this entity that occurs in the treatment phase of SLE and Still's disease.We describe here 8 cases of secondary HLH, their primary triggers and treatment response.

Sequestosome 1 Is Part of the Interaction Network of VAPB

VAPB (Vesicle-Associated-membrane Protein-associated protein B) is a tail-anchored membrane protein of the endoplasmic reticulum that can also be detected at the inner nuclear membrane. As a component of many contact sites between the endoplasmic reticulum and other organelles, VAPB is engaged in multiple protein interactions with a plethora of binding partners. A mutant version of VAPB, P56S-VAPB, which results from a single point mutation, is involved in a familial form of amyotrophic lateral sclerosis (ALS8). We performed RAPIDS (rapamycin- and APEX-dependent identification of proteins by SILAC) to identify proteins that interact with or are in close proximity to P56S-VAPB. The mutation abrogates the interaction of VAPB with many known binding partners. Here, we identify Sequestosome 1 (SQSTM1), a well-known autophagic adapter protein, as a major interaction/proximity partner of P56S-VAPB. Remarkably, not only the mutant protein, but also wild-type VAPB interacts with SQSTM1, as shown by proximity ligation assays and co-immunoprecipiation experiments.

Family form of dilated cardiomyopathy

Cardiomyopathy (CMP) is classified into familial and non-familial, which reflects the need to study the genetic basis of the disease. The article describes a clinical case of a familial form of non-compact cardiomyopathy in combination with a dilated form of cardiomyopathy. The article provides data of echocardiographic and MRI studies. The diagnosis was confirmed by genetic research, there was revealed a mutation in the MYH7 gene p.IIe201Thr in a heterozygous state, which is associated with the development of non-compact cardiomyopathy and dilated form of cardiomyopathy.

WDR13: A Novel Gene Implicated in Non-Syndromic Intellectual Disability

Investigating novel genetic variants involved in intellectual disability (ID) development is essential. X-linked intellectual disability (XLID) accounts for over 10% of all cases of ID in males. XLID genes are involved in many cellular pathways and processes. Some of them are not specific to the development and functioning of the neural system. The implementation of exome sequencing simplifies the search for novel variants, especially those less expected. Here, we describe a nonsense variant of the XLID gene, WDR13. The mutation c.757C>T (p.Arg253Ter) was uncovered by X-chromosome exome sequencing in males with a familial form of intellectual disability. Quantitative PCR (qPCR) analysis showed that variant c.757C>T caused a significant decrease in WDR13 expression in the patient's fibroblast. Moreover, it dysregulated other genes linked to intellectual disability, such as FMR1, SYN1, CAMK2A, and THOC2. The obtained results indicate the pathogenic nature of the detected variant and suggest that the WDR13 gene interacts with other genes essential for the functioning of the nervous system, especially the synaptic plasticity process.

RET Proto-Oncogene Mutational Analysis in 45 Iranian Patients Affected with Medullary Thyroid Carcinoma: Report of a New Variant

Background. The aim of this study was to identify germline mutation of the RET (rearranged during transfection) gene in patients with medullary thyroid carcinoma (MTC) and their first-degree relatives to find presymptomatic carriers for possible prophylactic thyroidectomy. Methods/Patients. We examined all six hot spot exons (exons 10, 11, 13, and 14–16) of the RET gene by PCR and bidirectional Sanger sequencing in 45 Iranian patients with MTC (either sporadic or familial form) from 7 unrelated kindred and 38 apparently sporadic cases. First-degree relatives of RET positive cases were also genotyped for index mutation. Moreover, presymptomatic carriers were referred to the endocrinologist for further clinical management and prophylactic thyroidectomy if needed. Results. Overall, the genetic status of all of the participants was determined by RET mutation screening, including 61 affected individuals, 22 presymptomatic carriers, and 29 genetically healthy subjects. In 37.5% (17 of 45) of the MTC referral index patients, 8 distinct RET germline mutations were found, including p.C634R (35.3%), p.M918T (17.6%), p.C634Y (11.8%), p.C634F (5.9%), p.C611Y (5.9%), p.C618R (5.9%), p.C630R (5.9%), p.L790F (5.9%), and one uncertain variant p.V648I (5.9%). Also, we found a novel variant p.H648R in one of our apparently sporadic patients. Conclusion. RET mutation detection is a promising/golden screening test and provides an accurate presymptomatic diagnostic test for at-risk carriers (the siblings and offspring of the patients) to consider prophylactic thyroidectomy. Thus, according to the ATA recommendations, the screening of the RET proto-oncogene is indicated for patients with MTC.

Two Sequences Variations of the E768D Mutation Found in Familial Medullary Thyroid Carcinomas

Medullary thyroid cancer or MTC is present in sporadic form (75% of cases) and in familial form (25% of cases), in this latter situation, the MTC is a part of Multiple Endocrine Neoplasia type 2 (MEN 2). The MEN2 is divided into MEN2A, MEN2B and FMTC or isolated familial MTC. The MEN2 are rare hereditary disease, transmitted as an autosomal dominant mode, linked to mutations of the RET gene. The discovery of a mutation in the RET proto-oncogene by molecular biology techniques in a index case of MTC confirms the diagnosis of familial and allows the genetic testing of healthy clinically related index case: those who carry the genetic mutation, will be offered prophylactic thyroidectomy before any biological or clinical manifestation. The genetic analysis of the RET gene was performed by PCR / sequencing. The E768D mutation was found in the exon 13 of the RET gene in 2 differences sequences forms (GAG/GAC et GAG/GAT). This mutation, already described, found in the FMTC.

Clinical and genetic heterogeneity of micronodular adrenal hyperplasia

Micronodular adrenal hyperplasia is a rare cause of ACTH-independent Cushing syndrome. It can be divided into two entities: primary pigmented nodular adrenocortical disease (PPNAD) and non-pigmented micronodular adrenocortical disease, among which familial and sporadic forms are distinguished. The most common is the genetically determined familial form PPNAD, as one of the components of Carney complex. The vast majority of patients have identifiable pathogenic variants in the PRKAR1A gene. In addition to the PRKAR1A gene mutations, inactivating mutations in the genes encoding phosphodiesterases (PDE11A4 and PDE8B), as well as PRKACA gene amplification, have been described in individuals with isolated forms. Despite the relative antiquity of the description of micronodular adrenal hyperplasia and the Carney comlex, a detailed study of pathophysiological mechanisms, genetic and clinical aspects of this pathology, nowadays, clinicians continue to face «atypical» cases. Thus, the nature of this disease is not well understood and requires further research. This review presents the accumulated data on micronodular adrenal hyperplasia, genetics aspects, and also describes 2 unique clinical cases of isolated PPNAD with unilateral adrenalectomy results.

Description of Joint Alterations Observed in a Family Carrying p.Asn453Ser COMP Variant: Clinical Phenotypes, In Silico Prediction of Functional Impact on COMP Protein and Stability, and Review of the Literature

The role of genetics in the development of osteoarthritis is well established but the molecular bases are not fully understood. Here, we describe a family carrying a germline mutation in COMP (Cartilage Oligomeric Matrix Protein) associated with three distinct phenotypes. The index case was enrolled for a familial form of idiopathic early-onset osteoarthritis. By screening potential causal genes for osteoarthritis, we identified a heterozygous missense mutation of COMP (c.1358C>T, p.Asn453Ser), absent from genome databases, located on a highly conserved residue and predicted to be deleterious. Molecular dynamics simulation suggests that the mutation destabilizes the overall COMP protein structure and consequently the calcium releases from neighboring calcium binding sites. This mutation was once reported in the literature as causal for severe multiple epiphyseal dysplasia (MED). However, no sign of dysplasia was present in the index case. The mutation was also identified in one of her brothers diagnosed with MED and secondary osteoarthritis, and in her sister affected by an atypical syndrome including peripheral inflammatory arthritis of unknown cause, without osteoarthritis nor dysplasia. This article suggests that this mutation of COMP is not only causal for idiopathic early-onset osteoarthritis or severe MED, but can also be associated to a broad phenotypic variability with always joint alterations.