Mohr-Tranebjaerg syndrome (MTS) is a rare X-linked recessive neurodegenerative disorder caused by pathogenic variants in the TIMM8A gene. TIMM8A, also known as Deafness-Dystonia Peptide-1 (DDP1) is a mitochondrial intermembrane space protein involved in the import and insertion of hydrophobic membrane proteins from the cytoplasm into the mitochondrial inner membrane. MTS typically presents early-onset progressive hearing loss, dystonia, visual impairment, and cognitive decline. Here, we report a case of a male adolescent with a previously undescribed variant in TIMM8A, associated with progressive dystonia but no hearing loss, highlighting the clinical variability of MTS. A 16-year-old male was referred for genetic evaluation due to a 6-year history of progressive dystonia, motor coordination difficulties, and iron deposits in the basal ganglia detected by brain MRI. Family history revealed mild motor abnormalities in his maternal uncle and recurrent muscle spasms in his mother. Whole-exome sequencing (WES) identified a c.98_101dupAGCA variant in TIMM8A in hemizygosity, classified as likely pathogenic. This variant causes a frameshift leading to a truncated protein. The patient inherited the variant from his mother, who is heterozygous for the mutation. Although the patient lacks the characteristic early-onset hearing loss seen in MTS, his neurological presentation and the imaging findings are consistent with the syndrome. This case underscores the phenotypic heterogeneity of Mohr-Tranebjaerg syndrome, where patients may present with prominent neurological symptoms such as dystonia without the hallmark auditory dysfunction. The identification of a novel TIMM8A variant expands the mutational spectrum of this rare disorder and provides insights into genotype-phenotype correlations. The absence of hearing loss in this patient raises important questions about the variability in the expression of the mutated TIMM8A. This report highlights a novel TIMM8A mutation associated with Mohr-Tranebjaerg syndrome, presenting primarily with dystonia and iron accumulation in the basal ganglia. The findings contribute to the understanding of the clinical spectrum of MTS and emphasize the importance of genetic testing in patients with unexplained progressive neurological symptoms.

Background/Objectives: The Mediator (MED) complex is an essential regulator of RNA polymerase II transcription. There is increasing evidence that pathogenic variants in several MED subunits are the cause of neurodegenerative and neurodevelopmental phenotypes, collectively referred to as "MEDopathies". This review aims to summarize current knowledge on the genetic basis, clinical manifestations, and neuroradiological features of MED-related disorders. Methods: We undertook a narrative synthesis of the literature focusing on the MED subunits most commonly associated with neurological disorders, including MED1, MED8, MED11, MED12/MED12L, MED13/MED13L, MED14, MED17, MED20, MED23, MED25, MED27, and CDK8. Sources included peer-reviewed genetic, clinical, and imaging studies, supplemented by relevant case reports and cohort analyses. In addition, representative facial phenotypes associated with selected MED variants (MED11, MED12, MED13, MED13L, MED25) were visualized for educational purposes using artificial intelligence-based image generation derived from standardized clinical descriptors. Results: All MEDopathies show converging clinical patterns: global developmental delay/intellectual disability, hypotonia, epilepsy, speech disorders, and behavioral comorbidity. Non-neurological involvement, such as craniofacial or cardiac anomalies, is subunit-specific. Neuroradiological features include callosal abnormalities (agenesis, thinning, dysmorphia), delayed or hypomyelination, progressive cerebral and cerebellar atrophy, basal ganglia signaling changes, pontine hypoplasia, and, in MED27 deficiency, a "hot cross bun" sign. Gene-specific constellations emphasize catastrophic infantile progression (MED11), X-linked syndromes with callosal defects (MED12/MED12L), language-dominant phenotypes (MED13), and syndromic intellectual disability with systemic features (MED13L). Conclusions: The growing spectrum of MEDopathies argues for their recognition as a unified nosological group with overlapping clinical and radiological signatures. Characteristic MRI constellations may serve as diagnostic clues and guide targeted molecular testing. Future directions include longitudinal imaging to describe disease progression and the integration of genomic data with curated clinical radiological datasets to refine genotype-phenotype correlations.

Mental retardation, X-linked, syndromic, Houge type (MRXSHG) is a form of mental retardation characterized by intellectual disability, speech and language impairments, and early-onset seizures. It has been recently recorded in Online Mendelian Inheritance in Man (OMIM), and only 10 cases have been reported in the literature so far. To highlight the novel neuroimaging findings in the pediatric X-linked intellectual disability with a missense mutation of connector enhancer of kinase suppressor of RAS2 (CNKSR2) gene. We present a case of intellectual disability, refractory epilepsy, speech and language delay with subtle dysmorphism, and behavioral issues in an 11-year-old boy with novel neuroimaging findings in a CNKSR2 gene with missense mutation. Brain MRI revealed involvement of the basal ganglia, predominantly the neostriatum, and along with the subependymal aspects with focal cavitations involving, especially the bilateral caudate heads. There was relative sparing of the globus pallidi and posterior putamina bilaterally. Whole-exome sequencing identified a hemizygous missense pathogenic variant in the CNKSR2 gene. The mother was found to be an asymptomatic carrier. This case report highlights the rare missense mutation in the CNKSR2 gene and abnormal neuroimaging findings, which further provide information about the phenotypic characteristics of X-linked syndromic intellectual disability.

Polygenic score (PGS) computations assume an additive model of gene action because associations between phenotypes and alleles at different loci are compounded, ignoring interactions between alleles or loci let alone between genotype and environment. Consequently, PGSs are subject to the same objections that invalidated traditional heritability analyses in the 1970s. Thus, PGSs should not be used in the social sciences.

Allan-Herndon-Dudley syndrome (AHDS) is a very rare, X-linked psychomotor disability syndrome with delayed myelination, almost exclusively affecting boys. We present a case of a 4-year-old boy with AHDS who was found cyanotic, with intermittent vomiting and paroxysmal convulsions about 4 h after his parents went out, and was then taken to the hospital, where he eventually died the next day. The autopsy revealed foreign bodies in the tiny bronchi and alveoli of the deceased, congestion, and punctate hemorrhage in multiple organs, consistent with the diagnosis of asphyxia. Compared with a normally developing 4-year-old boy, the deceased showed cerebral atrophy and cerebral edema, and Luxol Fast Blue (LFB) stain indicated delayed cerebellar, hippocampal, and basal ganglia development and myelination. A novel frameshift mutation c.584delG in the SLC16A2 gene was detected. Family lineage investigation showed that the mutation was also detected in the deceased's 8-year-old brother and biological mother. The present work enriches the profile mutations in SLC16A2 related to AHDS and emphasizes the importance of autopsy and postmortem genetic analysis in such cases.