Rapid Deployment of Whole Slide Imaging for Primary Diagnosis in Surgical Pathology at Stanford Medicine: Responding to Challenges of the COVID-19 Pandemic.

CONTEXT.­: Stanford Pathology began stepwise subspecialty implementation of whole slide imaging (WSI) in 2018 soon after the first US Food and Drug Administration approval. In 2020, during the COVID-19 pandemic, the Centers for Medicare & Medicaid Services waived the requirement for pathologists to perform diagnostic tests in Clinical Laboratory Improvement Amendments (CLIA)-licensed facilities. This encouraged rapid implementation of WSI across all surgical pathology subspecialties. OBJECTIVE.­: To present our experience with validation and implementation of WSI at a large academic medical center encompassing a caseload of more than 50 000 cases per year. DESIGN.­: Validation was performed independently for 3 subspecialty services with a diagnostic concordance threshold above 95%. Analysis of user experience, staffing, infrastructure, and information technology was performed after department-wide expansion. RESULTS.­: Diagnostic concordance was achieved in 96% of neuropathology cases, 100% of gynecologic pathology cases, and 98% of immunohistochemistry cases. After full implementation, 8 high-capacity scanners were operational, with whole slide images generated on greater than 2000 slides per weekday, accounting for approximately 80% of histologic slides at Stanford Medicine. Multiple modifications in workflow and information technology were needed to improve performance. Within months of full implementation, most attending pathologists and trainees had adopted WSI for primary diagnosis. CONCLUSIONS.­: WSI across all surgical subspecialities is achievable at scale at an academic medical center; however, adoption required flexibility to adjust workflows and develop tailored solutions. WSI at scale supported the health and safety of medical staff while facilitating high-quality patient care and education during COVID-19 restrictions.

Reflections on the constraints and opportunities in therapy in Rett syndrome.

More than 20 years of clinical and research experience with affected people in the British Isles has provided insight into particular challenges for therapists, educators, or parents wishing to facilitate learning and to support the development of skills in people with Rett syndrome. This paper considers the challenges in two groups: those due to constraints imposed by the disabilities associated with the disorder and those stemming from the opportunities, often masked by the disorder, allowing the development of skills that depend on less-affected areas of the brain. Because the disorder interferes with the synaptic links between neurones, the functions of the brain that are most dependent on complex neural networks are the most profoundly affected. These functions include speech, memory, learning, generation of ideas, and the planning of fine movements, especially those of the hands. In contrast, spontaneous emotional and hormonal responses appear relatively intact. Whereas failure to appreciate the physical limitations of the disease leads to frustration for therapist and client alike, a clear understanding of the better-preserved areas of competence offers avenues for real progress in learning, the building of satisfying relationships, and achievement of a quality of life.

NTNG1 mutations are a rare cause of Rett syndrome.

A translocation that disrupted the netrin G1 gene (NTNG1) was recently reported in a patient with the early seizure variant of Rett syndrome (RTT). The netrin G1 protein (NTNG1) has an important role in the developing central nervous system, particularly in axonal guidance, signalling and NMDA receptor function and was a good candidate gene for RTT. We recruited 115 patients with RTT (females: 25 classic and 84 atypical; 6 males) but no mutation in the MECP2 gene. For those 52 patients with epileptic seizure onset in the first 6 months of life, CDKL5 mutations were also excluded. We aimed to determine whether mutations in NTNG1 accounted for a significant subset of patients with RTT, particularly those with the early onset seizure variant and other atypical presentations. We sequenced the nine coding exons of NTNG1 and identified four sequence variants, none of which were likely to be pathogenic. Mutations in the NTNG1 gene appear to be a rare cause of RTT but NTNG1 function demands further investigation in relation to the central nervous system pathophysiology of the disorder.

Predictive value of the early clinical signs in Rett disorder.

The British Isles Survey for Rett has registered 1,159 cases over up to 20 years. Indicators of health and severity, recorded at intervals throughout life, are drawn from clinical examinations, reports and postal questionnaires. This study aimed to establish the stability and predictive value of an early severity score based on muscle tone, locomotor ability, feeding difficulty, scoliosis and epilepsy. Data from people with clinically documented classic or non-classic Rett and health records over 20-30 years indicate that severity scores tend to increase throughout the first 15 years and then to stabilise in mild and severe, classic and non-classic Rett. Severity scores before regression reflect later severity scores within relatively wide inter-quartile ranges. In general, the adult severity level is around 40 points above the pre-regression level for classic Rett and around 20 points for non-classic Rett. High early severity scores are associated with reduced cumulative survival. Used with caution, early signs are helpful in diagnosis and prognosis. The mutations T158M, R255X and R168X are generally associated with more severe and R306C and R133C with less severe disease but exceptions make these unreliable predictors of outcome.

Abnormal general movements in girls with Rett disorder: the first four months of life.

An apparently normal early development was one of the initial criteria for classical Rett syndrome. However, several investigators considered Rett syndrome to be a developmental disorder manifesting very soon after birth. Videos of 14 infants with Rett disorder were carefully assessed for their spontaneous movements, in particular general movements (GMs), during the first 4 months of life. A detailed analysis clearly demonstrated that none of the infants had normal GMs. However, a specific abnormal GM pattern could not be detected for Rett disorder. The abnormal GMs described here, and their individual developmental trajectories are different from the abnormal GMs described in infants with acquired brain lesion. Our study is the first to apply specific standardised measures of early spontaneous movements to infants with Rett syndrome, proving conclusively that the disorder is manifest within the first weeks of life.

Dimensional phenotypic analysis and functional categorisation of mutations reveal novel genotype-phenotype associations in Rett syndrome.

We aimed to improve the understanding of genotype-phenotype correlations in Rett syndrome (RS) by adopting a novel approach to categorising phenotypic dimensions - separating typicality of presentation, outcome severity and age of onset - and by classifying MECP2 mutations strictly by predicted functional attributes. MECP2 mutation screening results were available on 190 patients with a clinical diagnosis of RS (140 cases with classic RS, 50 with atypical RS). 135 cases had identified mutations. Of the 140 patients, 116 with classic RS (82.9%) had an identified mutation compared with 19 of 50 patients (38%) with an atypical presentation. Cases with early onset of regression and seizures, and those with clinical features that might indicate alternative aetiologies, were less likely to have mutations. Individuals with late truncating mutations had a less typical presentation than cases with missense and early truncating mutations, presumably reflecting greater residual function of MECP2 protein. Individuals with early truncating mutations had a more severe outcome than cases with missense and late truncating mutations. These findings held when restricting the analysis to cases over 15 years of age and classic cases only. Previous findings of variation in severity among the common mutations were confirmed. The approach to phenotypic and genotypic classification adopted here allowed us to identify genotype-phenotype associations in RS that may aid our understanding of pathogenesis and also contribute to clinical knowledge on the impact of different types of mutations.

Is the early development of girls with Rett disorder really normal?

An apparently normal early development was one of the initial criteria for classical Rett syndrome. However, several investigators considered Rett syndrome to be a developmental disorder manifesting very soon after birth. Videos of 22 Rett cases were assessed carefully for movements, posture, and behavior during the first 6 mo of life. All signs that deviated from the normal standard were recorded meticulously. Special attention was paid to the face, the hands, and body movements. A detailed analysis clearly demonstrated an abnormal quality of general movements (100%), tongue protrusion (62%), postural stiffness (58%), asymmetric eye opening and closing (56%), abnormal finger movements (52%), hand stereotypies (42%), bursts of abnormal facial expressions (42%), bizarre smile (32%), tremor (28%), and stereotyped body movements (15%). Our study is the first to apply specific standardized measures of early spontaneous movements to Rett infants, proving conclusively that the disorder is manifested within the first months of life. Although not necessarily specific, the signs that we have observed will be of value in alerting clinicians to the possibility of the diagnosis at an early stage, when intervention is likely to be most effective.

Results of surgery for scoliosis in Rett syndrome.

The British Isles Survey for Rett Syndrome stores longitudinal health data from clinical examinations and postal questionnaires to monitor health and severity in Rett syndrome, including the presence and severity of scoliosis and the effects of corrective surgery. Scoliosis is rarely present at birth (3% before regression) but usually appears by 25 years (87%). The degree tends to increase with growth and by 16 to 20 years, 43% (75 of 173) of cases with classic Rett syndrome reported severe or operated scoliosis. Surgical correction was reported in 91 classic cases. Following initial postoperative recovery, families considered that the operation had improved general well-being for 84% of individuals (42 of 50 classic cases with postoperative health reports). Thirteen of 50 patients walked independently before surgery, and 12 patients did so following surgery; 2 stopped walking, and 1 who had not walked began to do so. Scoliosis surgery usually benefited sitting posture (82% better, 10% worse), chest episodes (52% better, 6% worse), and digestion of food (42% better, 6% worse). However, toilet function was improved in only 10% and deteriorated in 20%. Families reported short-term problems at operation in 48% (24 of 50) and minor recurrence of scoliosis in 22% (11 of 50). Surgery in a specialized unit is satisfactory management for severe scoliosis in Rett syndrome. Recommendations include planning for surgery when the curve passes 40 degrees, ensuring optimal nutrition before and after surgery, robust fixture of the whole spine in two stages, familiarization of the surgical team with the individual and the disorder before the operation, and inclusion of the main carer in the hospital care team. Parents form an important part of the management team. Families also require support during and after this stressful major procedure.

The mid-point of passive hip rotation range is an indicator of hip rotation in gait in cerebral palsy.

This study investigated the strength of any linear relationship between femoral anteversion and passive hip rotations, with rotation of the limb during gait. The data of 29 subjects (38 legs) with cerebral palsy (CP) were reviewed. Passive examination data were correlated with hip rotations during the whole gait cycle, and in stance only. Hip rotation in gait correlated significantly with passive external rotation (r=0.51-0.54), femoral anteversion (r=0.43-0.47), and passive internal rotation (r=0.36-0.41). The mid-point of passive hip rotation range correlated best with hip rotation in the stance phase of gait (r=0.57-0.58).

Kinematic and kinetic gait characteristics of normal children walking at a range of clinically relevant speeds.

Kinematic and kinetic data were obtained from 36 normal children who walked at five different clinically relevant speeds, which were mostly slower than normal speed. Speed groups were normalized for body height. Speed significantly affected most of the stride parameters, joint angles, joint moments, and the ground reaction force in all three planes of motion. The effects of speed were not always the same over the whole range of speeds studied. The clinical relevance of these findings is that when comparing pathologic gait characteristics with those of normal children, these should be derived from the same walking speed. This may help to differentiate between effects caused by speed and underlying pathology.