Heterozygous loss-of-function mutations in the X-linked CASK gene cause progressive microcephaly with pontine and cerebellar hypoplasia (MICPCH) and severe intellectual disability (ID) in females. Different CASK mutations have also been reported in males. The associated phenotypes range from nonsyndromic ID to Ohtahara syndrome with cerebellar hypoplasia. However, the phenotypic spectrum in males has not been systematically evaluated to date. We identified a CASK alteration in 8 novel unrelated male patients by targeted Sanger sequencing, copy number analysis (MLPA and/or FISH) and array CGH. CASK transcripts were investigated by RT-PCR followed by sequencing. Immunoblotting was used to detect CASK protein in patient-derived cells. The clinical phenotype and natural history of the 8 patients and 28 CASK-mutation positive males reported previously were reviewed and correlated with available molecular data. CASK alterations include one nonsense mutation, one 5-bp deletion, one mutation of the start codon, and five partial gene deletions and duplications; seven were de novo, including three somatic mosaicisms, and one was familial. In three subjects, specific mRNA junction fragments indicated in tandem duplication of CASK exons disrupting the integrity of the gene. The 5-bp deletion resulted in multiple aberrant CASK mRNAs. In fibroblasts from patients with a CASK loss-of-function mutation, no CASK protein could be detected. Individuals who are mosaic for a severe CASK mutation or carry a hypomorphic mutation still showed detectable amount of protein. Based on eight novel patients and all CASK-mutation positive males reported previously three phenotypic groups can be distinguished that represent a clinical continuum: (i) MICPCH with severe epileptic encephalopathy caused by hemizygous loss-of-function mutations, (ii) MICPCH associated with inactivating alterations in the mosaic state or a partly penetrant mutation, and (iii) syndromic/nonsyndromic mild to severe ID with or without nystagmus caused by CASK missense and splice mutations that leave the CASK protein intact but likely alter its function or reduce the amount of normal protein. Our findings facilitate focused testing of the CASK gene and interpreting sequence variants identified by next-generation sequencing in cases with a phenotype resembling either of the three groups.

(1) Parents caring for children and adolescents with rare diseases fear the long-term progression of the child’s disease and the loss of their parental role. The aim of this study was to examine the quality of life, mental health and associated protective factors of mothers and fathers caring for children with rare diseases requiring mechanical long-term ventilation. (2) In a cross-sectional design, data on quality of life, mental health, coping mechanisms, social support and family functioning from n = 75 affected families were collected using standardized psychometric questionnaires. (3) Mothers compared to fathers were significantly more impaired in their quality of life and mental health. Protective factors significantly associated with the respective outcomes for mothers were coping mechanisms, social support and family functioning, whereas for fathers solely the latter was found to be significant. Multiple regression analyses showed that family functioning may be the most important predictor of quality of life and mental health. (4) The results support the need for family-oriented care in parents of children with rare diseases. To reach optimal efficiency, health care providers should not only screen parents for psychosocial impairment but also provide interventions that consider gender-specific differences in psychological health.

Objective: Hereditary spastic paraplegia (HSP) is a highly heterogeneous neurologic disorder characterized by lower‐extremity spasticity. Here, we set out to determine the genetic basis of an autosomal dominant, pure, and infantile‐onset form of HSP in a cohort of 8 patients with a uniform clinical presentation.Methods: Trio whole‐exome sequencing was used in 5 index patients with infantile‐onset pure HSP to determine the genetic cause of disease. The functional impact of identified genetic variants was verified using bioinformatics and complementary cellular and biochemical assays.Results: Distinct heterozygous KPNA3 missense variants were found to segregate with the clinical phenotype in 8 patients; in 4 of them KPNA3 variants had occurred de novo. Mutant karyopherin‐α3 proteins exhibited a variable pattern of altered expression level, subcellular distribution, and protein interaction.Interpretation: Our genetic findings implicate heterozygous variants in KPNA3 as a novel cause for autosomal dominant, early‐onset, and pure HSP. Mutant karyopherin‐α3 proteins display varying deficits in molecular and cellular functions, thus, for the first time, implicating dysfunctional nucleocytoplasmic shuttling as a novel pathomechanism causing HSP. ANN NEUROL 2021;90:738–750

Spinal muscular atrophy (SMA) is a neurodegenerative disorder that is characterized by progressive weakness, respiratory insufficiency, and dysphagia. Due to symptom burden and disease progress, its care management and impact on daily life can severely burden the families of affected children. The objectives of this study are (1) to explore the health care experiences and (2) to investigate the psychosocial needs of the parents of children with SMA. In total, 29 parents of patients with SMA participated in our study. All children received supportive therapy (e.g., physiotherapy) and most were dependent on medical equipment. Parents perceived the health care positively regarding team quality, communication and access to medical care. An assessment of the impact of the child’s health on the family (e.g., stressors, burden, consequences) is not routinely integrated into care. On average, parents reported low to medium levels of psychosocial needs. Due to the complex health care needs of SMA patients, the health care experiences of parents can provide relevant information on care delivery. To enhance the inclusion of psychosocial and emotional issues, as well as family impact, into routine health care, health care providers should be sensitive towards parental needs for consistency in the health care team and emotional aspects and, if applicable, address them proactively.

Mucolipidosis type II (MLII), an ultra-rare lysosomal storage disorder, manifests as a fatal multi-systemic disease. Mental inhibition and progressive neurodegeneration are commonly reported disease manifestations. Nevertheless, longitudinal data on neurocognitive testing and neuroimaging lack in current literature. This study aimed to provide details on central nervous system manifestations in MLII. All MLII patients with at least one standardized developmental assessment performed between 2005 and 2022 were included by retrospective chart review. A multiple mixed linear regression model was applied. Eleven patients with a median age of 34.0 months (range 1.6–159.6) underwent 32 neurocognitive and 28 adaptive behaviour assessments as well as 14 brain magnetic resonance imagings. The scales used were mainly BSID-III (42%) and VABS-II (47%). Neurocognitive testing (per patient: mean 2.9, standard deviation (SD) 2.0) performed over 0–52.1 months (median 12.1) revealed profound impairment with a mean developmental quotient of 36.7% (SD 20.4) at last assessment. The patients showed sustained development; on average, they gained 0.28 age-equivalent score points per month (confidence interval 0.17–0.38). Apart from common (63%) cervical spinal stenosis, neuroimaging revealed unspecific, non-progressive abnormalities (i.e., mild brain atrophy, white matter lesions). In summary, MLII is associated with profound developmental impairment, but not with neurodegeneration and neurocognitive decline.

Background: Leukodystrophies are a group of rare genetic diseases that primarily affect the white matter of the central nervous system. The broad spectrum of metabolic and pathological causes leads to manifestations at any age, most often in childhood and adolescence, and a variety of symptoms. Leukodystrophies are usually progressive, resulting in severe disabilities and premature death. Progressive visual impairment is a common symptom. Currently, no overview of the manifold neuro-ophthalmologic manifestations and visual impact of leukodystrophies exists. Methods: Data from 217 patients in the Hamburg leukodystrophy cohort were analyzed retrospectively for neuro-ophthalmologic manifestations, age of disease onset, and magnetic resonance imaging, visual evoked potential, and optical coherence tomography findings and were compared with data from the literature. Results: In total, 68% of the patients suffered from neuro-ophthalmologic symptoms, such as optic atrophy, visual neglect, strabismus, and nystagmus. Depending on the type of leukodystrophy, neuro-ophthalmologic symptoms occurred early or late during the course of the disease. Magnetic resonance imaging scans revealed pathologic alterations in the visual tract that were temporally correlated with symptoms. Conclusions: The first optical coherence tomography findings in Krabbe disease and metachromatic leukodystrophy allow retinal assessments. Comprehensive literature research supports the results of this first overview of neuro-ophthalmologic findings in leukodystrophies.