Neu-Laxova syndrome (NLS) is a rare autosomal-recessive disorder characterized by severe fetal growth restriction, microcephaly, a distinct facial appearance, ichthyosis, skeletal anomalies, and ...perinatal lethality. The pathogenesis of NLS remains unclear despite extensive clinical and pathological phenotyping of the >70 affected individuals reported to date, emphasizing the need to identify the underlying genetic etiology, which remains unknown. In order to identify the cause of NLS, we conducted a positional-mapping study combining autozygosity mapping and whole-exome sequencing in three consanguineous families affected by NLS. Surprisingly, the NLS-associated locus identified in this study was solved at the gene level to reveal mutations in PHGDH, which is known to be mutated in individuals with microcephaly and developmental delay. PHGDH encodes the first enzyme in the phosphorylated pathway of de novo serine synthesis, and complete deficiency of its mouse ortholog recapitulates many of the key features of NLS. This study shows that NLS represents the extreme end of a known inborn error of serine metabolism and highlights the power of genomic sequencing in revealing the unsuspected allelic nature of apparently distinct clinical entities.
Ehlers–Danlos syndrome (EDS) describes a group of clinical entities in which the connective tissue, primarily that of the skin, joint and vessels, is abnormal, although the resulting clinical ...manifestations can vary widely between the different historical subtypes. Many cases of hereditary disorders of connective tissue that do not seem to fit these historical subtypes exist. The aim of this study is to describe a large series of patients with inherited connective tissue disorders evaluated by our clinical genetics service and for whom a likely causal variant was identified. In addition to clinical phenotyping, patients underwent various genetic tests including molecular karyotyping, candidate gene analysis, autozygome analysis, and whole-exome and whole-genome sequencing as appropriate. We describe a cohort of 69 individuals representing 40 families, all referred because of suspicion of an inherited connective tissue disorder by their primary physician. Molecular lesions included variants in the previously published disease genes
B3GALT6
,
GORAB
,
ZNF469
,
B3GAT3
,
ALDH18A1
,
FKBP14
,
PYCR1
,
CHST14
and
SPARC
with interesting variations on the published clinical phenotypes. We also describe the first recessive EDS-like condition to be caused by a recessive
COL1A1
variant. In addition, exome capture in a familial case identified a homozygous truncating variant in a novel and compelling candidate gene,
AEBP1
. Finally, we also describe a distinct novel clinical syndrome of cutis laxa and marked facial features and propose
ATP6V1E1
and
ATP6V0D2
(two subunits of vacuolar ATPase) as likely candidate genes based on whole-genome and whole-exome sequencing of the two families with this new clinical entity. Our study expands the clinical spectrum of hereditary disorders of connective tissue and adds three novel candidate genes including two that are associated with a highly distinct syndrome.
Molecular karyotyping has rapidly become the test of choice in patients with neurocognitive phenotypes, but studies of its clinical utility have largely been limited to outbred populations. In ...consanguineous populations, single-gene recessive causes of neurocognitive phenotypes are expected to account for a relatively high percentage of cases, thus diminishing the yield of molecular karyotyping. The aim of this study was to test the clinical yield of molecular karyotyping in the highly consanguineous population of Saudi Arabia.
We have reviewed the data of 584 patients with neurocognitive phenotypes (mainly referred from pediatric neurology clinics), all evaluated by a single clinical geneticist.
At least 21% of tested cases had chromosomal aberrations that are likely disease-causing. These changes include both known and novel deletion syndromes. The higher yield of molecular karyotyping in this study as compared with the commonly cited 11% can be explained by our ability to efficiently identify single-gene disorders, thus enriching the samples that underwent molecular karyotyping for de novo chromosomal aberrations. We show that we were able to identify a causal mutation in 37% of cases on a clinical basis with the help of autozygome analysis, thus bypassing the need for molecular karyotyping.
Our study confirms the clinical utility of molecular karyotyping even in highly consanguineous populations.
To understand the contribution of Mendelian mutations to the burden of undiagnosed diseases that are suspected to be genetic in origin, we developed a next-generation sequencing-based multiplexing ...assay that encompasses the ~3000 known Mendelian genes. This assay, which we term the Mendeliome, comprises 13 gene panels based on clinical themes, covering the spectrum of pediatric and adult clinical genetic medicine. We explore how these panels compare with clinical whole exome sequencing (WES).
We tested 2357 patients referred with suspected genetic diagnoses from virtually every medical specialty. A likely causal mutation was identified in 1018 patients, with an overall clinical sensitivity of 43 %, comparing favorably with WES. Furthermore, the cost of clinical-grade WES is high (typically more than 4500 US dollars), whereas the cost of running a sample on one of our panels is around 75-150 US dollars, depending on the panel. Of the "negative" cases, 11 % were subsequently found by WES to harbor a likely causal mutation in a known disease gene (largely in genes identified after the design of our assay), as inferred from a representative sample of 178. Although our study population is enriched for consanguinity, 245 (24 %) of solved cases were autosomal dominant and 35 (4 %) were X-linked, suggesting that our assay is also applicable to outbred populations.
Despite missing a significant number of cases, the current version of the Mendeliome assay can account for a large proportion of suspected genetic disorders, and provides significant practical advantages over clinical WES.
Background
The appropriate age and weight for surgical repair of atrioventricular septal defect (AVSD) is an area of controversy. We aimed to study the effect of weight and age at the time of ...surgical repair for complete AVSD in children less than 2 years of age on postoperative outcomes. A retrospective data review was performed for patients who underwent the AVSD repair from 2012 to 2019 at our institutions. Our primary outcome was the postoperative in-hospital length of stay (LOS). Secondary outcomes included total positive pressure ventilation (PPV), ventilation time, maximum vasoactive–inotropic score (max VIS), and other postoperative complications.
Results
The study included fifty patients. The median age was 191 days, and the median weight was 4.38 kg at the time of surgery. Weight < 4 kg was associated with longer PPV time and postoperative in-hospital LOS (
p
value of 0.033 and 0.015, respectively). Additionally, they had higher max VIS at 24 h and 48 h than the other groups with bodyweight 4–5.9 kg or ≥ 6 kg (
p
value of 0.05 and 0.027, respectively). Patients with older age or lower weight at operation had a longer in-hospital LOS and total length of PPV after surgery. There were no postoperative in-hospital deaths.
Conclusions
Older age and lower weight at the time of surgical repair of atrioventricular septal defect could be independent predictors of prolonged postoperative in-hospital length of stay and total length of positive pressure ventilation.
External contamination (“soiling”) of the incident surface is a major limiting factor for solar technologies. A 5-year field glass coupon study was conducted to better understand external ...contamination and its effects; compare cleaning methods and the use of preventative coatings; and explore the abrasion resulting from cleaning to advise on accelerated abrasion testing. Test sites included the cities of Dubai (UAE), Kuwait City (Kuwait), Mesa (AZ), Mumbai (India), and Sacramento (CA). Through the 5-year cumulative study, dry brush, water spray, and wet sponge and squeegee cleaning methods were compared to no cleaning. Optical microscopy was used to obtain images, including representative color images, grayscale images for object analysis, and oblique images for coating integrity assessment. A thresholding protocol was developed to analyze and distinguish specimens using the ImageJ software. Optical performance was quantified using a spectrophotometer, including comprehensive optical characterization (transmittance, reflectance, and absorptance in addition to forward- and back-scattering). Atomic force microscopy was used to verify the abrasion damage morphology, including the width and depth of surface scratches. Analysis of the results included correlation of optical performance and particle area coverage, rank order (by coating or location), and the acceleration factor for abrasion damage. The efficacy of external cleaning was more readily distinguished from the effectiveness of antisoiling coatings. The acceleration factor for dry brush cleaning of a porous silica coating was found to be on the order of unity.
Figure A: An outdoor study (including assessment of the contamination level, optical performance, and scratch morphology) was conducted using fielded coupons (five locations, five materials of interest, and four cleaning methods). A 5-year field glass coupon study was conducted to better understand external contamination and its effects; compare cleaning methods and the use of preventative coatings; and explore the abrasion resulting from cleaning to advise on accelerated abrasion testing. Test sites included the cities of Dubai (UAE), Kuwait City (Kuwait), Mesa (AZ), Mumbai (India), and Sacramento (CA). Through the 5-year cumulative study, dry brush, water spray, and wet sponge and squeegee cleaning methods were compared to no cleaning. Optical microscopy was used to obtain images, including representative color images, grayscale images for object analysis, and oblique images for coating integrity assessment. A thresholding protocol was developed to analyze and distinguish specimens using the ImageJ software. Optical performance was quantified using a spectrophotometer, including comprehensive optical characterization (transmittance, reflectance, and absorptance in addition to forward- and back-scattering). Atomic force microscopy was used to verify the abrasion damage morphology, including the width and depth of surface scratches. Analysis of the results included correlation of optical performance and particle area coverage, rank order (by coating or location), and the acceleration factor for abrasion damage. Display omitted
•Contamination and its effect on transmittance reflect the complexity and stochastic nature of soiling.•Median object size ranged from 2 to 3, 6–20, or 10–30 μm in number, area, and volumetric distributions.•The efficacy of external cleaning was more readily distinguished from the effectiveness of antisoiling coatings.•Damage unique to Mumbai may come from precipitation (the impact and pH of rain).•The acceleration factor for dry brush cleaning of a porous silica coating was found to be on the order of unity.
To evaluate the diagnostic utility of publicly funded clinical exome sequencing (ES) for patients with suspected rare genetic diseases.
We prospectively enrolled 297 probands who met eligibility ...criteria and received ES across 5 sites in Ontario, Canada, and extracted data from medical records and clinician surveys. Using the Fryback and Thornbury Efficacy Framework, we assessed diagnostic accuracy by examining laboratory interpretation of results and assessed diagnostic thinking by examining the clinical interpretation of results and whether clinical-molecular diagnoses would have been achieved via alternative hypothetical molecular tests.
Laboratories reported 105 molecular diagnoses and 165 uncertain results in known and novel genes. Of these, clinicians interpreted 102 of 105 (97%) molecular diagnoses and 6 of 165 (4%) uncertain results as clinical-molecular diagnoses. The 108 clinical-molecular diagnoses were in 104 families (35% diagnostic yield). Each eligibility criteria resulted in diagnostic yields of 30% to 40%, and higher yields were achieved when >2 eligibility criteria were met (up to 45%). Hypothetical tests would have identified 61% of clinical-molecular diagnoses.
We demonstrate robustness in eligibility criteria and high clinical validity of laboratory results from ES testing. The importance of ES was highlighted by the potential 40% of patients that would have gone undiagnosed without this test.
Objective: This study was designed to screen patients who sought medical services in the Pediatric Outpatient Department, Al-Adan Hospital, Kuwait for overweight. Subjects and Methods: Body mass ...index (BMI) was used to screen 361 children (≤10 years old) for risk of overweight and overweight (BMI between 85th and 94th, and ≥95th percentile, respectively). Overweight children were fully examined and abdominal ultrasound was done for each of them. Results: Of the 361 children, 52 (14.41%) and 77 (21.33%) were at risk of overweight and overweight, respectively. There was a slight male predominance for overweight (40 males, 51.95%, compared to 37 females, 48.05%) and within the overweight category; 28 males (70%) and 26 females (70.27%) were above 6 years of age. In overweight children over 6 years, 4 (7.41%) had hepatomegaly with fatty changes and 3 (5.56%) had blood pressure above the 95th percentile for age and sex. Conclusion: Childhood overweight at Al-Adan Hospital was high and increased with age. Hence childhood screening for overweight is recommended at an early age because it is an important risk factor of chronic diseases.
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