Aug 2026· Journal of Child Neurology· pp.
8830738261472512
· 0 citations· 10 references
Medicine
TL;DR
Two sisters homozygous for the recurrent TANGO2 variant c.460G>A, identified in a family of Hispanic/Latino ancestry, who exhibited divergent clinical presentations highlight intrafamilial variability within the recognized TDD spectrum and underscore the importance of early recognition of neurologic and endocrine features as potential red flags.
Abstract
BackgroundTANGO2-related disorder (TDD) is a rare autosomal recessive condition characterized by episodic metabolic crises, rhabdomyolysis, encephalopathy, and life-threatening cardiac arrhythmias, with marked phenotypic variability that often contributes to delayed diagnosis.Case presentationWe report 2 sisters homozygous for the recurrent TANGO2 variant c.460G>A (p.Gly154Arg), identified in a family of Hispanic/Latino ancestry, who exhibited divergent clinical presentations. The older sibling presented with developmental delay and recurrent fasting-induced hypoglycemia associated with hyperCKemia and episodic weakness, whereas the younger sibling showed early hypotonia, ataxia, behavioral dysregulation, and subclinical hypothyroidism without initial metabolic crises. Brain magnetic resonance imaging studies were normal in both patients. In both cases, routine metabolic testing was largely unremarkable between episodes, and early manifestations were interpreted within isolated subspecialty frameworks, delaying diagnostic integration.ConclusionThese cases highlight intrafamilial variability within the recognized TDD spectrum and underscore the importance of early recognition of neurologic and endocrine features as potential red flags. Prompt molecular diagnosis is essential to guide anticipatory management and reduce morbidity and mortality.
A novel homozygous missense variant in RNF216 gene c.1055T>G (p.(Phe352Cys)) in three siblings with Gordon Holmes syndrome is reported, contributing to the limited knowledge of GHS and highlighting the importance of hypogonadotropic hypogonadism treatment and close observation of neurological symptoms that may develop over time.
A 5.5-year-old girl born to consanguineous parents who presented with refractory early-onset seizures, severe global developmental delay, growth failure, and microcephaly is described, highlighting the critical role of whole-exome sequencing in accurately delineating complex phenotypes in consanguineous populations.
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A retrospective multicenter case series of seven previously unreported individuals with heterozygous FBXW7 variants identified through clinical genetic testing expands the phenotypic spectrum associated with FBXW7-related neurodevelopmental disorder and highlights variable expressivity and incomplete penetrance.
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This study expands the mutational landscape of JS in the Iranian population and underscores the utility of WES as a first-tier diagnostic tool for JS and related ciliopathies.
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TANGO2 deficiency disorder is an ultra-rare autosomal recessive condition characterized by life-threatening metabolic crises with rhabdomyolysis and cardiac arrhythmias. Patients with 22q11.2 deletion syndrome are at increased risk when a pathogenic variant occurs in the remaining allele, yet this dual diagnosis remains underrecognized as clinicians often attribute all manifestations to the primary genetic condition. We report a case of a child with confirmed 22q11.2 deletion syndrome in whom a coexisting variant in the TANGO2 gene was diagnosed at the age of 5 after first metabolic crisis with rhabdomyolysis. A girl with 22q11.2 deletion syndrome diagnosed in infancy exhibited global developmental delay and chronic excessive sleepiness attributed to her established diagnosis. At age 5, she experienced her first metabolic crisis during pneumonia with severe rhabdomyolysis (creatine kinase >100,000 U/L), features inconsistent with isolated 22q11.2 deletion syndrome. Two additional metabolic crises occurred at age 7 before exome sequencing revealed a hemizygous TANGO2 variant c.536G>A, confirming TANGO2 deficiency. A previously unreported hemizygous missense variant c.536G>A (p.Gly138Glu) in the TANGO2 gene (NM_152906.7) was identified and verified by NGS-based deep amplicon sequencing and Sanger direct sequencing; segregation analysis confirmed paternal inheritance with the maternal allele deleted within the 22q11.2 region. Following diagnosis, B-vitamin supplementation, coenzyme Q10, L-carnitine, and gastrostomy tube placement were initiated to ensure consistent hydration and prevent prolonged periods without nutrition, a known crisis trigger. The patient achieved 4 years of crisis-free stability with reduced daytime sleepiness. At age 11, she remains stable without further crises. This case demonstrates that exome sequencing should be pursued early when atypical features emerge in patients with established genetic diagnoses. The sustained crisis-free period following gastrostomy placement supports proactive nutritional intervention in TANGO2 patients with feeding difficulties. Clinicians must recognize that microdeletion syndrome patients can harbor variants unmasking additional autosomal recessive conditions requiring distinct management.
Ewa Grzywna-Rozenek, Ł. Sędek, M. Rydzanicz et al.· BMC Pediatrics· 0 citations
King–Denborough syndrome is a rare RYR1-related congenital myopathy characterized by dysmorphic features, muscle weakness, and susceptibility to malignant hyperthermia, often posing a diagnostic challenge in early infancy. We report a one-year-old female child presenting with developmental delay and generalized hypotonia. Clinical evaluation revealed craniofacial dysmorphism, bilateral ptosis, and esotropia, raising suspicion of an underlying congenital myopathy. Initial laboratory and imaging workup were inconclusive except for transient elevation of creatine kinase. Whole exome sequencing identified a heterozygous missense variant in the RYR1 gene (c.14126C>T; p.Thr4709Met), along with a likely pathogenic FOXP1 variant. In view of the characteristic clinical phenotype, a diagnosis of King–Denborough syndrome was considered. The child was managed with supportive therapy and developmental interventions, and caregivers were counselled regarding the risk of malignant hyperthermia. This case underscores the importance of clinicogenetic correlation in diagnosing rare myopathies and highlights the need for early recognition to enable appropriate counselling and prevention of anaesthetic complications.
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