Heterozygous variants in MYH10 associated with neurodevelopmental disorders and congenital anomalies with evidence for primary cilia-dependent defects in Hedgehog signaling.

PURPOSE: Nonmuscle myosin II complexes are master regulators of actin dynamics that play essential roles during embryogenesis with vertebrates possessing 3 nonmuscle myosin II heavy chain genes, MYH9, MYH10, and MYH14. As opposed to MYH9 and MYH14, no recognizable disorder has been associated with MYH10. We sought to define the clinical characteristics and molecular mechanism of a novel autosomal dominant disorder related to MYH10. METHODS: An international collaboration identified the patient cohort. CAS9-mediated knockout cell models were used to explore the mechanism of disease pathogenesis. RESULTS: We identified a cohort of 16 individuals with heterozygous MYH10 variants presenting with a broad spectrum of neurodevelopmental disorders and variable congenital anomalies that affect most organ systems and were recapitulated in animal models of altered MYH10 activity. Variants were typically de novo missense changes with clustering observed in the motor domain. MYH10 knockout cells showed defects in primary ciliogenesis and reduced ciliary length with impaired Hedgehog signaling. MYH10 variant overexpression produced a dominant-negative effect on ciliary length. CONCLUSION: These data presented a novel genetic cause of isolated and syndromic neurodevelopmental disorders related to heterozygous variants in the MYH10 gene with implications for disrupted primary cilia length control and altered Hedgehog signaling in disease pathogenesis.

Atypical idiopathic intracranial hypertension presenting as cyclic vomiting syndrome: a case report.

BACKGROUND: Idiopathic intracranial hypertension is a disorder of increased intracranial pressure in the absence of cerebrospinal outflow obstruction, mass lesion, or other underlying cause. It is a rare phenomenon in prepubertal children and is most typically found in women of childbearing age. The classic presentation consists of headaches, nausea, vomiting, and visual changes; however, children present more atypically. We report a case of idiopathic intracranial hypertension in an otherwise healthy, 4-year-old child with atypical symptoms resembling those of cyclic vomiting syndrome. CASE PRESENTATION: A 4-year-old Caucasian, otherwise healthy, male child presented to our emergency department with episodic intermittent early-morning vomiting occurring once every 1-3 weeks without interepisodic symptoms, starting 10 months prior. With outpatient metabolic, autoimmune, endocrine, allergy, and gastroenterology work-up all unremarkable, he was initially diagnosed with cyclic vomiting syndrome. Discovery of mild optic nerve sheath distension on magnetic resonance imaging of the brain 10 months after symptom onset led to inpatient admission and a lumbar puncture notable for an opening pressure of 47 mmHg, with normal cell count and protein levels. He had no changes in visual acuity or optic disc edema on dilated fundoscopic examination. The patient was started on acetazolamide, with resolution of episodic emesis at his last follow-up visit 12 weeks after discharge. CONCLUSIONS: Idiopathic intracranial hypertension presents atypically in prepubescent children, with about one-fourth presenting asymptomatically, and only 13-52% presenting with "classic" symptoms. With a prevalence of only 0.6-0.7 per 100,000, much remains unknown regarding the underlying pathophysiology in this demographic. Cyclic vomiting syndrome, however, has a much higher prevalence in this age group, with a prevalence of 0.4-1.9 per 100. It is thought to be an idiopathic, periodic disorder of childhood, often linked to neurological conditions such as abdominal migraines, epilepsy, mitochondrial disorders, and structural lesions such as chiari malformation and posterior fossa tumors. While cyclic vomiting syndrome is thought to have a benign course, untreated idiopathic intracranial hypertension can have long-term detrimental effects, such as visual loss or even blindness. We present a case of idiopathic intracranial hypertension presenting with symptoms resembling cyclic vomiting syndrome in a 4-year-old child, diagnosed 10 months after initial onset of symptoms. We aim to demonstrate the need for a high level of clinical suspicion and the need for further investigation into underlying pathophysiology in this vulnerable population.

Loss of function mutations in GEMIN5 cause a neurodevelopmental disorder.

GEMIN5, an RNA-binding protein is essential for assembly of the survival motor neuron (SMN) protein complex and facilitates the formation of small nuclear ribonucleoproteins (snRNPs), the building blocks of spliceosomes. Here, we have identified 30 affected individuals from 22 unrelated families presenting with developmental delay, hypotonia, and cerebellar ataxia harboring biallelic variants in the GEMIN5 gene. Mutations in GEMIN5 perturb the subcellular distribution, stability, and expression of GEMIN5 protein and its interacting partners in patient iPSC-derived neurons, suggesting a potential loss-of-function mechanism. GEMIN5 mutations result in disruption of snRNP complex assembly formation in patient iPSC neurons. Furthermore, knock down of rigor mortis, the fly homolog of human GEMIN5, leads to developmental defects, motor dysfunction, and a reduced lifespan. Interestingly, we observed that GEMIN5 variants disrupt a distinct set of transcripts and pathways as compared to SMA patient neurons, suggesting different molecular pathomechanisms. These findings collectively provide evidence that pathogenic variants in GEMIN5 perturb physiological functions and result in a neurodevelopmental delay and ataxia syndrome.

Doublecortin Mutation in an Adolescent Male.

Doublecortin (DCX) mutations cause abnormal development of the DCX protein that normally aids in neuronal migration during fetal development. These mutations lead to lissencephaly, or the appearance of a "smooth brain," which is varying levels of pachygyria or agyria in severe cases. Many genetic variants of the mutation have been identified, and an even greater range of phenotypic presentations have been described in the literature. The X-linked lissencephaly (DCX) mutation leads to an X-linked gender-dependent condition that causes subcortical heterotopia in females and lissencephaly in males. The authors report the case of a 13-year-old male who presented to our clinic for new-onset seizure disorder. He had a past medical history of developmental delay and features of autism spectrum disorder which was diagnosed at age 5 years at an outside clinic. Magnetic resonance imaging (MRI) brain at age 5 years showed pachygyria of the frontal and temporal lobes. After extensive genetic testing over the course of over a decade, the patient was found to have a de novo mutation in the DCX gene diagnosed via whole-exome sequencing. Specifically, he was found to have a mosaic mutation of the DCX gene as a c.30-31 deletion. His previous MRI findings were consistent with a diagnosis of X-linked sporadic lissencephaly sequence and included mainly a diffuse bilateral pachygyria (isolated lissencephaly sequence X chromosome). Thickening of the cortex and pachygyria or agyria are classic findings of lissencephaly, but do not help specify any mutation in the gene, of which there are over 70 possibilities. Our patient is unique in that most individuals with DCX mutation have infantile seizures, severe intellectual disability, orthopedic complications, and postnatal microcephaly, which our patient does not have.

Post-Trial Sustainability and Scalability of the Benefits of a Medical Home for High-Risk Children with Medical Complexity.

OBJECTIVE: To assess the sustainability of the benefits relative to usual care of a medical home providing comprehensive care for high-risk children with medical complexity (≥2 hospitalizations or ≥1 pediatric intensive care unit [PICU] admission in the year before enrollment) after we made comprehensive care our standard practice and expanded the program. STUDY DESIGN: We conducted pre-post comparisons of the rate of children with serious illness (death, PICU admission, or >7-day hospitalization) and health-system costs observed after program expansion (March 2014-June 2015) to those during the clinical trial (March 2011-August 2013) for each of the trial's treatment groups (usual care, n = 96, and comprehensive care, n = 105; primary analyses), and among all children given comprehensive care (nPost-trial = 233, including trial usual care children who transitioned to comprehensive care post-trial and newly enrolled medically complex children, and nTrial = 105; secondary analyses). We also analyzed the findings for the trial patients as a 2-phase stepped-wedge study. RESULTS: In intent-to-treat analyses, rates of children with serious illness and costs were reduced or unchanged post-trial vs trial for the trial's usual care group (rate ratio [RR], 0.36; 95% CI, 0.20-0.64; cost ratio [CR], 0.68; 95% CI, 0.28-1.68), the trial's comprehensive care group (RR, 0.74; 95% CI, 0.39-1.41; CR, 0.67; 95% CI, 0.51-0.89), and among all children given comprehensive care (RR, 0.97; 95% CI, 0.61-1.52; CR, 0.75; 95% CI, 0.61-0.93). Conservative stepped-wedge analyses identified overall benefits with comprehensive care across both study periods (RR, 0.46; 95% CI, 0.30-0.72; CR, 0.64; 95% CI, 0.43-0.99). CONCLUSIONS: Major benefits of comprehensive care did not diminish with post-trial program expansion.

Glycyl tRNA Synthetase (GARS) Gene Variant Causes Distal Hereditary Motor Neuropathy V.

Distal hereditary motor neuropathies (dHMN) are a rare heterogeneous group of inherited disorders specifically affecting the motor axons, leading to distal limb neurogenic muscular atrophy. The GARS gene has been identified as a causative gene responsible for clinical features of dHMN type V in families from different ethnic origins and backgrounds. We present the first cohort of family members of Nigerian descent with a novel heterozygous p.L272R variant on the GARS gene. We postulate that this variant is the cause of dHMN-V in this family, leading to variable phenotypical expressions that are earlier than reported in previous cases. The exact cause for the observed clinical heterogeneity within the family is unknown. One explanation is that there are modifier genes that affect the phenotype. These cases highlight the possibility of considering pathogenic variants in the GARS gene as a potential cause of early onset axonal polyneuropathy with atypical presentation.

Effect of an enhanced medical home on serious illness and cost of care among high-risk children with chronic illness: a randomized clinical trial.

IMPORTANCE: Patient-centered medical homes have not been shown to reduce adverse outcomes or costs in adults or children with chronic illness. OBJECTIVE: To assess whether an enhanced medical home providing comprehensive care prevents serious illness (death, intensive care unit [ICU] admission, or hospital stay >7 days) and/or reduces costs among children with chronic illness. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial of high-risk children with chronic illness (≥3 emergency department visits, ≥2 hospitalizations, or ≥1 pediatric ICU admissions during previous year, and >50% estimated risk for hospitalization) treated at a high-risk clinic at the University of Texas, Houston, and randomized to comprehensive care (n = 105) or usual care (n = 96). Enrollment was between March 2011 and February 2013 (when predefined stopping rules for benefit were met) and outcome evaluations continued through August 31, 2013. INTERVENTIONS: Comprehensive care included treatment from primary care clinicians and specialists in the same clinic with multiple features to promote prompt effective care. Usual care was provided locally in private offices or faculty-supervised clinics without modification. MAIN OUTCOMES AND MEASURES: Primary outcome: children with a serious illness (death, ICU admission, or hospital stay >7 days), costs (health system perspective). Secondary outcomes: individual serious illnesses, medical services, Medicaid payments, and medical school revenues and costs. RESULTS: In an intent-to-treat analysis, comprehensive care decreased both the rate of children with a serious illness (10 per 100 child-years vs 22 for usual care; rate ratio [RR], 0.45 [95% CI, 0.28-0.73]), and total hospital and clinic costs ($16,523 vs $26,781 per child-year, respectively; cost ratio, 0.58 [95% CI, 0.38-0.88]). In analyses of net monetary benefit, the probability that comprehensive care was cost neutral or cost saving was 97%. Comprehensive care reduced (per 100 child-years) serious illnesses (16 vs 44 for usual care; RR, 0.33 [95% CI, 0.17-0.66]), emergency department visits (90 vs 190; RR, 0.48 [95% CI, 0.34-0.67]), hospitalizations (69 vs 131; RR, 0.51 [95% CI, 0.33-0.77]), pediatric ICU admissions (9 vs 26; RR, 0.35 [95% CI, 0.18-0.70]), and number of days in a hospital (276 vs 635; RR, 0.36 [95% CI, 0.19-0.67]). Medicaid payments were reduced by $6243 (95% CI, $1302-$11,678) per child-year. Medical school losses (costs minus revenues) increased by $6018 (95% CI, $5506-$6629) per child-year. CONCLUSIONS AND RELEVANCE: Among high-risk children with chronic illness, an enhanced medical home that provided comprehensive care to promote prompt effective care vs usual care reduced serious illnesses and costs. These findings from a single site of selected patients with a limited number of clinicians require study in larger, broader populations before conclusions about generalizability to other settings can be reached. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02128776.

Difference in central and peripheral recovery in a patient with severe axonal motor neuropathy and central nervous system involvement and review of literature.

In the literature, the term fulminant Guillain-Barré syndrome is used to refer to patients with Guillain-Barré syndrome with rapidly progressive and severe weakness and/or comatose state mimicking brain death. We present the case of a 53-year-old man with fulminant Guillain-Barré syndrome with discrepancy in central nervous system and peripheral nervous system recovery. Our review of literature confirms that these patients often have good and relatively rapid recovery of central nervous system function, whereas peripheral nervous system function is relatively delayed and often incomplete.

Dysferlinopathy presenting as rhabdomyolysis and acute renal failure.

Dysferlinopathies are a heterogeneous group of autosomal recessive muscle disorders resulting from defects or deficiencies in dysferlin. Reported phenotypes range from isolated hyperCKemia to muscular dystrophy. We present a 15-year-old male adolescent who was diagnosed with a dysferlinopathy after presenting with acute renal failure secondary to rhabdomyolysis.

Secondary erythromelalgia successfully treated with intravenous immunoglobulin.

Erythromelalgia is a rare condition characterized by episodic painful erythema and warmth often affecting, but not limited to, the distal extremities. This condition is notoriously difficult to treat. We report a young female patient with seronegative polyarthritis who presented with a 6-year history of recurrent bouts of painful erythema and swelling often triggered by minor trauma. An extensive evaluation was unremarkable. Several medical therapies provided limited and inconsistent relief of her symptoms over many years. Treatment with intravenous immunoglobulin significantly decreased the frequency and severity of her symptoms.