Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Encephalopathy has been demonstrated to be associated with respiratory syncytial virus bronchiolitis. In this study, the data on all patients less than 14 years of age hospitalized with respiratory syncytial virus bronchiolitis over the past 4 years was reviewed. Patients who had concomitant diagnoses consistent with neurologic disease underwent detailed chart review. There were 964 patients (age 0.1 to 13.6 years) with a diagnosis of respiratory syncytial virus bronchiolitis. Thirty-six of these patients had concurrent neurologic diagnoses. Twenty-four patients were excluded because of preexistent neurologic disorders, probable simple febrile seizures, or a history of epilepsy. Twelve respiratory syncytial virus-positive patients had definite neurologic complications without another recognized cause. Seven of these patients had seizures (predominantly generalized tonic-clonic and one with status epilepticus), three had generalized encephalopathy (marked hypotonia and decreased responsiveness) of whom two also developed esotropia. Two patients developed isolated esotropia. There was an incidence of neurologic complications of 1.2% (0.7% seizures) in a total of 964 patients with respiratory syncytial virus bronchiolitis. This percentage does not include presumed simple febrile seizures or exacerbations of preexisting seizure disorder (further 1.3%). Neurologic complications occur with respiratory syncytial virus bronchiolitis, and physicians and other caregivers should be aware of this entity as well as the favorable prognosis.
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PMID:Neurologic complications associated with respiratory syncytial virus. 1586 30

We describe the second case of congenital disorder of glycosylation type IL (CDG-IL) caused by deficiency of the ALG9 a1,2 mannosyltransferase enzyme. The female infant's features included psychomotor retardation, seizures, hypotonia, diffuse brain atrophy with delayed myelination, failure to thrive, pericardial effusion, cystic renal disease, hepatosplenomegaly, esotropia, and inverted nipples. Lipodystrophy and dysmorphic facial features were absent. Magnetic resonance imaging of the brain showed volume loss in the cerebral hemispheres and cerebellum and delayed myelination. Laboratory investigations revealed low levels of multiple serum proteins including antithrombin III, factor XI, and cholesterol. Hypoglycosylation was confirmed by the typical CDG type 1 pattern of serum transferrin analyzed by isoelectric focusing. A defect in the ALG9 enzyme was suggested by the accumulation of the DolPP-GlcNAc2Man6 and DolPP-GlcNAc2Man8 in the patient's fibroblasts and confirmed by mutation analysis: the patient is homozygous for the ALG9 mutation p.Y286C. The causal effect of the mutation was shown by complementation assays in alg9 deficient yeast cells. The child described here further delineates the clinical spectrum of CDG-IL and confirms the significant clinical overlap amongst CDG subtypes.
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PMID:CDG-IL: an infant with a novel mutation in the ALG9 gene and additional phenotypic features. 1594 70

A boy with chromosome 14 terminal (14q32.3) deletion presented with typical facial dysmorphism, mental retardation, and hypotonia. Ocular examination revealed esotropia, jerk nystagmus, microcornea, and retinal-choroidal colobomas. We report the first case of microcorneas and colobomas in association with chromosome 14 terminal deletion to help further define this clinical syndrome.
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PMID:Ocular manifestations of chromosome 14 terminal deletion. 1659 78

Abnormalities of deep cerebellar nuclei in Joubert syndrome have been previously reported only in rare autopsy cases. Epilepsy in association with Joubert syndrome is also rarely reported. In two new cases of patients with Joubert syndrome, bilateral hypoplasia of deep cerebellar nuclei was detected in vivo by magnetic resonance imaging. One of the patients had drug-resistant epilepsy. Both patients received clinical examination, electroencephalography, neuropsychologic testing, and high-resolution magnetic resonance imaging (1.5 T). Patient 1, a 7-year-old boy, had muscular hypotonia, periodic tachypnea, mild ataxia, global developmental delay, exotropia, and polydactyly. Patient 2, a 23-year-old woman, had muscular hypotonia, epilepsy with pharmacoresistant generalized tonic-clonic seizures, learning disability, esotropia, and mild gait ataxia. Abnormalities of deep cerebellar nuclei might contribute to the pathophysiology of epilepsy in patients with Joubert syndrome.
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PMID:Hypoplasia of deep cerebellar nuclei in joubert syndrome. 1943 86

Prader-Willi syndrome (PWS) is a complex genetic disorder, characterized by neonatal hypotonia, developmental delay, short stature, childhood obesity, hypogonadism, and characteristic facial features. Here we report a 21-year-old male who presented with uncontrolled glycemic status. He was diagnosed to have diabetes mellitus at the age of 15 with osmotic symptoms - polyuria, polydipsia, and polyphagia. In the early period, after diagnosis, his blood sugars were reasonably controlled with oral hypoglycemic agents. However, a year back, he was switched onto insulin therapy due to secondary OHA failure. On examination, his body mass index was 36 kg/m(2). He had bilateral gynecomastia, decreased biparietal diameter, almond shaped eyes with esotropia. He had hypogonadism and also had mild cognitive impairment. He did not have any proximal myopathy or other focal neurological deficits. Hormonal evaluation showed low testosterone and inappropriately normal fluorescence in situ hybridization suggestive of central hypogonadism. With fetal and neonatal hypotonia, delayed developmental milestones, hypogonadism, and early onset diabetes, he fulfilled the clinical criteria for the diagnosis of PWS. Multidisciplinary approach of clinicians together with family and social support are essential to bring out the optimal outcome for such syndromic cases.
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PMID:An unusual case of adolescent type 2 diabetes mellitus: Prader-Willi syndrome. 2745 71

Allan-Herndon-Dudley syndrome is a rare X-linked neurologic condition caused by mutations in monocarboxylate transporter 8 ( MCT8), which leads to deficient thyroid hormone transport. Typical features include severe cognitive impairment, truncal hypotonia, spastic paraplegia, weakness, and speech difficulties. Minimal literature exists describing the ocular findings in patients with Allan-Herndon-Dudley syndrome. We describe 4 male siblings affected with Allan-Herndon-Dudley syndrome with a novel nonsense mutation (Q90X) in the MCT8 protein. All affected siblings presented with classic findings of Allan-Herndon-Dudley syndrome, and each of the siblings also developed intermittent esotropia. This group of affected siblings represents the first consistent documentation of strabismus in Allan-Herndon-Dudley syndrome, suggesting a possible association between this clinical finding and the neurologic syndrome.
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PMID:Intermittent Esotropia in 4 Patients With Allan-Herndon-Dudley Syndrome. 2971 7

Mitochondrial aconitase is the second enzyme in the tricarboxylic acid (TCA) cycle catalyzing the interconversion of citrate into isocitrate and encoded by the nuclear gene ACO2. A homozygous pathogenic variant in the ACO2 gene was initially described in 2012 resulting in a novel disorder termed "infantile cerebellar retinal degeneration" (ICRD, OMIM#614559). Subsequently, additional studies reported patients with pathogenic ACO2 variants, further expanding the genetic and clinical spectrum of this disorder to include milder and later onset manifestations. Here, we report an international multicenter cohort of 16 patients (of whom 7 are newly diagnosed) with biallelic pathogenic variants in ACO2 gene. Most patients present in early infancy with severe truncal hypotonia, truncal ataxia, variable seizures, evolving microcephaly, and ophthalmological abnormalities of which the most dominant are esotropia and optic atrophy with later development of retinal dystrophy. Most patients remain nonambulatory and do no acquire any language, but a subgroup of patients share a more favorable course. Brain magnetic resonance imaging (MRI) is typically normal within the first months but global atrophy gradually develops affecting predominantly the cerebellum. Ten of our patients were homozygous to the previously reported c.336C>G founder mutation while the other six patients were all compound heterozygotes displaying 10 novel mutations of whom 2 were nonsense predicting a deleterious effect on enzyme function. Structural protein modeling predicted significant impairment in aconitase substrate binding in the additional missense mutations. This study provides the most extensive cohort of patients and further delineates the clinical, radiological, biochemical, and molecular features of ACO2 deficiency.
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PMID:Clinical, radiological, and genetic characteristics of 16 patients with ACO2 gene defects: Delineation of an emerging neurometabolic syndrome. 3068 4

Autosomal recessive variants in the adenosine deaminase, tRNA specific 3 ( ADAT3 ) gene cause a syndromic form of intellectual disability due to a loss of ADAT3 function. This disorder is characterized by developmental delay, intellectual disability, speech delay, abnormal brain structure, strabismus, microcephaly, and failure to thrive. A small subset of individuals with ADAT3 deficiency have other structural birth defects including atrial septal defect, patent ductus arteriosus, hypospadias, cryptorchidism, and micropenis. Here, we report a sibling pair with novel compound heterozygous missense variants that affect a conserved amino acid in the deaminase domain of ADAT3. These siblings have many of the features characteristic of this syndrome, including, intellectual disability, hypotonia, esotropia, failure to thrive, and microcephaly. Both had gastroesophageal reflux disease (GERD), feeding problems, and aspiration requiring thickening of feeds. Although they have no words, their communication abilities progressed rapidly when they began to use augmentative and alternative communication (AAC) devices. One of these siblings was born with an anterior congenital diaphragmatic hernia, which has not been reported previously in association with ADAT3 deficiency. We conclude that individuals with ADAT3 deficiency should be monitored for GERD, feeding problems, and aspiration in infancy. They may also benefit from the use of AAC devices and individualized educational programs that take into account their capacity for nonverbal language development. Additional studies in humans or animal models will be needed to determine if ADAT3 deficiency predisposes to the development of structural birth defects.
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PMID:Novel Missense Variants in ADAT3 as a Cause of Syndromic Intellectual Disability. 3168 66

The RNA exosome is an essential ribonuclease complex required for processing and/or degradation of both coding and non-coding RNAs. We identified five patients with biallelic variants in EXOSC5, which encodes a structural subunit of the RNA exosome. The clinical features of these patients include failure to thrive, short stature, feeding difficulties, developmental delays that affect motor skills, hypotonia and esotropia. Brain MRI revealed cerebellar hypoplasia and ventriculomegaly. While we ascertained five patients, three patients with distinct variants of EXOSC5 were studied in detail. The first patient had a deletion involving exons 5-6 of EXOSC5 and a missense variant, p.Thr114Ile, that were inherited in trans, the second patient was homozygous for p.Leu206His and the third patient had paternal isodisomy for chromosome 19 and was homozygous for p.Met148Thr. The additional two patients ascertained are siblings who had an early frameshift mutation in EXOSC5 and the p.Thr114Ile missense variant that were inherited in trans. We employed three complementary approaches to explore the requirement for EXOSC5 in brain development and assess consequences of pathogenic EXOSC5 variants. Loss of function for exosc5 in zebrafish results in shortened and curved tails/bodies, reduced eye/head size and edema. We modeled pathogenic EXOSC5 variants in both budding yeast and mammalian cells. Some of these variants cause defects in RNA exosome function as well as altered interactions with other RNA exosome subunits. These findings expand the number of genes encoding RNA exosome subunits linked to human disease while also suggesting that disease mechanism varies depending on the specific pathogenic variant.
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PMID:Biallelic variants in the RNA exosome gene EXOSC5 are associated with developmental delays, short stature, cerebellar hypoplasia and motor weakness. 3250 85

Mosaic genetic mutations may be somatic, germline, or "gonosomal" and have the potential to cause genetic syndromes, disorders, or malformations. Mutations can occur at any point in embryonic development and the timing determines the extent of distribution of the mutation throughout the body and different tissue types. The eye and visual pathway offer a unique opportunity to study somatic and gonosomal mosaic mutations as the eye consists of tissues derived from all three germ layers allowing disease pathology to be assessed with noninvasive imaging. In this review, we describe systemic and ocular manifestations in a child with mosaic Coffin-Siris syndrome. The patient presented with a significant medical history of accommodative esotropia and hyperopia, macrocephaly, polydactyly, global developmental delay, hypotonia, ureteropelvic junction (UPJ) obstruction, and brain MRI abnormalities. The ophthalmic findings in this patient were nonspecific, however, they are consistent with ocular manifestations reported in other patients with Coffin-Siris syndrome. We also review ophthalmic findings of select mosaic chromosomal and single-gene disorders. Ophthalmic assessment alongside clinical genetic testing may play an important role in diagnosis of genetic syndromes as well as understanding disease pathology, particularly when mosaicism plays a role.
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PMID:Systemic and ocular manifestations of a patient with mosaic ARID1A-associated Coffin-Siris syndrome and review of select mosaic conditions with ophthalmic manifestations. 3288 75


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