Acid sphingomyelinase (ASM)-deficient Niemann-Pick disease is an autosomal recessive lysosomal storage disorder caused by biallelic mutations in the SMPD1 gene. To date, around 185 mutations have been reported in patients with ASM-deficient NPD world-wide, but the mutation spectrum of this disease in India has not yet been reported. The aim of this study was to ascertain the mutation profile in Indian patients with ASMdeficient NPD. We sequenced SMPD1 in 60 unrelated families affected with ASM-deficient NPD. A total of 45 distinct pathogenic sequence variants were found, of which 14 were known and 31 were novel. The variants included 30 missense, 4 nonsense, and 9 frameshift (7 single base deletions and 2 single base insertions) mutations, 1 indel, and 1 intronic duplication. The pathogenicity of the novel mutations was inferred with the help of the mutation prediction software MutationTaster, SIFT, Polyphen-2, PROVEAN, and HANSA. The effects of the identified sequence variants on the protein structure were studied using the structure modeled with the help of the SWISS-MODEL workspace program. The p. (Arg542 Ã ) (c.1624C>T) mutation was the most commonly identified mutation, found in 22% (26 out of 120) of the alleles tested, but haplotype analysis for this mutation did not identify a founder effect for the Indian population. To the best of our knowledge, this is the largest study on mutation analysis of patients with Festschrift honoring John C. Carey
Parapharyngeal tumors are rare head and neck tumors which can present as an intraoral mass and can pose great challenge to anesthesiologists. The primary concern is the difficult airway due to gross anatomical distortion of the upper airway. Securing the airway in an awake state should be the primary goal of anesthesiologists to avoid catastrophic complications. Herewith, we report the successful use of C-MAC® video laryngoscope with the acute-angle D-BLADE™ in combination with Frova introducer for awake intubation in a patient with parapharyngeal mass after multiple attempts of failed fiber-optic intubation.
Pathogenic variations in SMPD1 lead to acid sphingomyelinase deficiency (ASMD), that is, Niemann‐Pick disease (NPD) type A and B (NPA, NPB), which is a recessive lysosomal storage disease. The knowledge of variant spectrum in Indian patients is crucial for early and accurate NPD diagnosis and genetic counseling of families. In this study, we recruited 40 unrelated pediatric patients manifesting symptoms of ASMD and subnormal ASM enzyme activity. Variations in SMPD1 were studied using Sanger sequencing for all exons, followed by interpretation of variants based on American College of Medical Genetics and Genomics & Association for Molecular Pathology (ACMG/AMP) criteria. We identified 18 previously unreported variants and 21 known variants, including missense, nonsense, deletions, duplications, and splice site variations with disease‐causing potential. Eight missense variants were functionally characterized using in silico molecular dynamic simulation and in vitro transient transfection in HEK293T cells, followed by ASM enzyme assay, immunoblot, and immunofluorescence studies. All the variants showed reduced ASM activity in transfected cells confirming their disease‐causing potential. The study provides data for efficient prenatal diagnosis and genetic counseling of families with NPD type A and B.
Abnormalities of secondary sexual differentiation manifest in varying degrees depending upon the severity of the underlying cause. Primary amenorrhea in phenotypic females is caused by several different factors, including hormonal imbalance, nutritional deficiency and sex differentiation abnormalities. Androgen insensitivity syndrome (AIS) accounts for a large proportion of such cases in phenotypic females but genetically male individuals. Over the past 10 years, we have collected data related to androgen insensitivity from more than 150 cases. The research identified several important but neglected facts about this syndrome; including the identification of mutations in 39% of the cases and the establishment of the cause of pathogenesis in 60% of them. The most intriguing facts were uncovered in relation to late presentation of the AIS cases, little awareness among patients and family members, no consensus on the age of performing gonadectomy, and reluctance of the patients to undergo recommended surgery. These issues need immediate attention to improve healthcare and management of AIS cases. This article summarizes our observations about AIS with an aim to spread awareness among patients and clinicians.
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