NGS-based expanded carrier screening for genetic disorders in North Indian population reveals unexpected results - a pilot study

Background

To determine the carrier frequency and pathogenic variants of common genetic disorders in the north Indian population by using next generation sequencing (NGS).

Methods

After pre-test counselling, 200 unrelated individuals (including 88 couples) were screened for pathogenic variants in 88 genes by NGS technology. The variants were classified as per American College of Medical Genetics criteria. Pathogenic and likely pathogenic variants were subjected to thorough literature-based curation in addition to the regular filters. Variants of unknown significance were not reported. Individuals were counselled explaining the implications of the results, and cascade screening was advised when necessary.

Results

Of the 200 participants, 52 (26%) were found to be carrier of one or more disorders. Twelve individuals were identified to be carriers for congenital deafness, giving a carrier frequency of one in 17 for one of the four genes tested (SLC26A4, GJB2, TMPRSS3 and TMC1 in decreasing order). Nine individuals were observed to be carriers for cystic fibrosis, with a frequency of one in 22. Three individuals were detected to be carriers for Pompe disease (frequency one in 67). None of the 88 couples screened were found to be carriers for the same disorder. The pathogenic variants observed in many disorders (such as deafness, cystic fibrosis, Pompe disease, Canavan disease, primary hyperoxaluria, junctional epidermolysis bullosa, galactosemia, medium chain acyl CoA deficiency etc.) were different from those commonly observed in the West.

Conclusion

A higher carrier frequency for genetic deafness, cystic fibrosis and Pompe disease was unexpected, and contrary to the generally held view about their prevalence in Asian Indians. In spite of the small sample size, this study would suggest that population-based carrier screening panels for India would differ from those in the West, and need to be selected with due care. Testing should comprise the study of all the coding exons with its boundaries in the genes through NGS, as all the variants are not well characterized. Only study of entire coding regions in the genes will detect carriers with adequate efficiency, in order to reduce the burden of genetic disorders in India and other resource poor countries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12881-020-01153-4.

Group B Streptococcus in Indian pregnant women: Its prevalence and risk factors

Purpose

To study the prevalence of group B streptococci (GBS) in Indian pregnant women and associated risk factors.

Methods

Four hundred and fifty pregnant women attending antenatal outpatient/inpatient department between 35-38 weeks of gestation were enrolled in the study. All enrolled subjects were assessed by a predefined proforma for their demographics, socio-economic characteristics, education, toilet habits, obstetric history and clinical outcome. Two cotton swabs each from lower vagina and rectum were collected and plated on selective solid media CHROM agar Strept B (CHROMagarTM) and selective Enrichment Broth LIM RambaQUICK StreptB broth (CHROMagarTM). Presumptive identification of GBS was growth of 1-3 mm grayish white β-hemolytic colonies on BAP or mauve coloured colonies on CHROM agar Strept B. All presumptively identified GBS were confirmed as group B streptococcus by automated identification system-Vitek MS (Bio Merieux).

Results

The recto vaginal colonization rate of GBS in this study was observed as 3.3% (n=15). GBS colonization was significantly associated with nulliparous women (p= 0.026) and use of western style toilet (p=0.017). GBS urinary tract infections was also seen more commonly in women with GBS rectovaginal colonization (p=0.002).

Conclusion

Due to the low GBS prevalence and no significant association with major risk factors, we recommend to institute universal screening of GBS in pregnant women, instead of risk based screening. Since this was a single centric study with low prevalence of GBS, its applicability may be limited, therefore further larger multi-centric prospective studies are required to understand the true GBS prevalence in Indian society.

Indian National Association for the Study of the Liver-Federation of Obstetric and Gynaecological Societies of India Position Statement on Management of Liver Diseases in Pregnancy

Liver diseases occurring during pregnancy can be serious and can progress rapidly, affecting outcomes for both the mother and fetus. They are a common cause of concern to an obstetrician and an important reason for referral to a hepatologist, gastroenterologist, or physician. Liver diseases during pregnancy can be divided into disorders unique to pregnancy, those coincidental with pregnancy, and preexisting liver diseases exacerbated by pregnancy. A rapid differential diagnosis between liver diseases related or unrelated to pregnancy is required so that specialist and urgent management of these conditions can be carried out. Specific Indian guidelines for the management of these patients are lacking. The Indian National Association for the Study of the Liver (INASL) in association with the Federation of Obstetric and Gynaecological Societies of India (FOGSI) had set up a taskforce for development of consensus guidelines for management of patients with liver diseases during pregnancy, relevant to India. For development of these guidelines, a two-day roundtable meeting was held on 26-27 May 2018 in New Delhi, to discuss, debate, and finalize the consensus statements. Only those statements that were unanimously approved by most members of the taskforce were accepted. The primary objective of this review is to present the consensus statements approved jointly by the INASL and FOGSI for diagnosing and managing pregnant women with liver diseases. This article provides an overview of liver diseases occurring in pregnancy, an update on the key mechanisms involved in its pathogenesis, and the recommended treatment options.

Early versus delayed cord clamping in small for gestational age infants and iron stores at 3 months of age - a randomized controlled trial

Background

Delayed cord clamping is the standard of care in infants not requiring resuscitation; however effects of cord clamping strategies have not been evaluated systematically in small for gestational age (SGA) infants. The primary objective was to compare effects of delayed cord clamping (DCC) and early cord clamping (ECC) on serum ferritin at 3 months in SGA infants born at ≥35 weeks. The secondary objectives were to compare hematological parameters, clinical outcomes in neonatal period and growth at 3 months of age.

Methods

All eligible infants with fetal growth restriction were randomized to two groups, DCC at 60 s or ECC group in which the cord was clamped immediately after birth.

Results

Total of 142 infants underwent randomization and subsequently 113 infants underwent definite inclusion. At 3 months, the median (IQR) serum ferritin levels were higher in DCC group, compared to ECC; 86 ng/ml (43.35–134.75) vs 50.5 ng/ml (29.5–83.5), p = 0.01. Fewer infants had iron deficiency in DCC group compared to ECC group; 9 (23.6%) vs 21 (47.7%), p = 0.03 [NNT being 4; 95% CI (2–25)].The proportion of infants with polycythemia was significantly higher in DCC group; 23 (41.81) % vs 12 (20.6%), p = 0.01. There was no difference in proportion of infants with symptomatic polycythemia or those who underwent partial exchange transfusions. Clinical outcomes and mortality were similar.

Conclusions

DCC improves iron stores in SGA infants ≥35 weeks at 3 months of age without increasing the risk of symptomatic polycythemia, need for partial exchange transfusions or morbidities associated with polycythemia.

Trial registration

Our trial was retrospectively registered on 29th May 2015 through Clinical trials registry India. Registration number: CTRI 2015/05/005828.

Growth hormone deficiency and cardiovascular risk factors in childhood cancer survivors

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Background: Childhood cancer survivors (CCS) have a high frequency of growth hormone deficiency (GHD) and risk of early cardiovascular disease (CVD). This study examined the relations between GHD and risk factors for CVD in CCS. Methods: Anthropometrics, blood pressure, lipids, growth hormone (GH) stimulation test, dual-energy x-ray absorptiometry, abdominal CT, and insulin resistance (IR) (euglycemic, hyperinsulinemic clamp - low M/lbm signifies IR) were obtained in 174 CCS, mean age 15±2 years and 89 healthy sibling controls, mean age 13.5±3 years. Linear regression evaluated the relations between GHD and CVD risk factors, adjusted for sex, age, pubertal stage, and body mass index (BMI) or visceral fat. Results: 62 CCS (36%) had GHD. There were no significant measurement differences between non-GHD CCS and controls. Compared to controls, GHD CCS who never received GH (N = 34) had greater BMI (24.8 vs 20.8 kg/m2, p < 0.0001), percent body fat (36.1% vs 25.8%, p < 0.0001), visceral fat (34.8 vs 19.6 cm2, p < 0.0001), and triglycerides (TG) (120.2 vs 83.8 mg/dL, p = 0.001) and were more IR (M/lbm 11.1 vs 14.2 mg/kg/min, p = 0.0006). Adjustment for BMI and visceral fat did not change the IR or TG results. GHD CCS currently on GH had lower BMI (21.9 kg/m2, p = 0.02), percent body fat (31.2%, p = 0.08), and visceral fat (26.5 cm2, p = 0.03) compared to those not treated. IR and TG were not different between treated and not treated GHD CCS. Conclusions: GHD is a common finding in CCS and is significantly associated with adiposity, IR, and elevated TG.There is a suggestion that GH treatment had a positive impact on adiposity, but not IR and TG levels. These study findings imply that CVD risk factors are present in CCS with GHD independent of body fatness, suggesting that the cancer diagnosis or treatments received may lead to early cardiovascular disease in childhood cancer survivors.

No significant financial relationships to disclose.

Cardiometabolic risk in survivors of childhood cancer who received hematopoietic cell transplant (HCT)

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Background: Evidence suggests that survivors of childhood cancer are at increased risk for cardiovascular disease (CVD) and type 2 diabetes with even higher risk in those who received HCT. The purpose of this study was to compare the cardiometabolic risk factor profile in HCT patients and healthy sibling controls. Methods: Measures of insulin resistance (euglycemic hyperinsulinemic clamp adjusted for lean body mass [Mlbm], low Mlbm represents insulin resistance), fasting glucose, insulin, lipids, anthropometry, blood pressure (BP), and carotid artery compliance and distensibility (lower values represent arterial stiffness) were determined in 87 children and young adults (current age 27.3 yr, 57% male) who had received HCT for hematologic malignancy during childhood (mean age at HCT 11.8 yr) and 55 healthy sibling controls (current age=25.2 yr, 51% male). Linear regression models were used to evaluate risk factors between groups after adjusting for age, gender, pubertal stage, body mass index (BMI), and carotid lumen diameter (stiffness measures only). Results: Metabolic syndrome (ATP III criteria for adults, modified criteria for children) was present in 13 (14.9%) HCT survivors and 4 (7.3%) controls (p=0.19). Thirty-one (35.6%) survivors and 9 (16.4%) controls had two or more components of the metabolic syndrome (p=0.11). There were no differences between groups for BMI, waist circumference, percent body fat, or BP. HCT survivors had higher triglycerides, fasting glucose and insulin, lower HDL cholesterol, arterial distensibility, and were more insulin resistant (Table). Conclusions: HCT survivors have increased cardiometabolic risk factors independent of obesity suggesting that cancer itself and/or associated treatment exposures have a direct influence on CVD risk and that early screening and management of cardiometabolic risk factors should be considered in HCT survivors.

[Table: see text]

No significant financial relationships to disclose.

Vertical transmission of Salmonella paratyphi A

Neonatal enteric fever is a rare but life-threatening illness. Patients may present with varying severity, Salmonella enterica serotype Typhi causing more severe illness than Salmonella enterica serotype Paratyphi A. Salmonella enterica serotype Paratyphi A is considered to cause milder infection with fewer complications. We report a rare case of vertical transmission of Salmonella enterica serotype Paratyphi A with severe complications and high mortality. Even though there are case reports of vertical transmission of Salmonella enterica serotype Typhi, to our knowledge, this is the first case report of vertical transmission of Salmonella enterica serotype ParatyphiA. The role of blood culture in accurate diagnosis and treatment is also discussed.

Anaesthetic management of the parturient with protein S deficiency and lumboperitoneal shunt

Protein S, a vitamin K-dependent plasma protein, is a cofactor for protein C, an essential component of the regulatory system of coagulation. We describe the anesthetic management of a parturient with protein S deficiency and an indwelling lumboperitoneal shunt, which was placed following transverse and sagittal sinus thrombosis. She was treated with aspirin and enoxaparin during pregnancy and underwent caesarean section under general anaesthesia without complication.