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.

• MeSH
• alfa karyoferiny genetika   MeSH
• dospělí MeSH
• fenotyp MeSH
• heterozygot MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• předškolní dítě MeSH
• rodokmen MeSH
• sekvenování exomu metody   MeSH
• spastická paraplegie dědičná genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alfa karyoferiny MeSH
• KPNA3 protein, human MeSH Prohlížeč

CONTEXT: 4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date. OBJECTIVE: To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy. DESIGN: An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated. SETTING: This was a multicenter retrospective study using information collected from 3 predominant centers. PATIENTS: A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included. MAIN OUTCOME MEASURES: Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts. RESULTS: The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients. CONCLUSIONS: Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder.

• Klíčová slova
• 4H leukodystrophy, POLR3-related leukodystrophy, hypogonadotropic hypogonadism, hypomyelination,
• MeSH
• biologická variabilita populace MeSH
• dědičné demyelinizační nemoci CNS komplikace   epidemiologie   genetika   MeSH
• dítě MeSH
• DNA řízené RNA-polymerasy genetika   MeSH
• dospělí MeSH
• genetická heterogenita MeSH
• hypogonadismus epidemiologie   etiologie   MeSH
• kohortové studie MeSH
• kojenec MeSH
• lidé MeSH
• mitochondriální nemoci komplikace   epidemiologie   genetika   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace MeSH
• nemoci endokrinního systému epidemiologie   etiologie   genetika   MeSH
• novorozenec MeSH
• poruchy růstu epidemiologie   etiologie   genetika   MeSH
• předškolní dítě MeSH
• průřezové studie MeSH
• retrospektivní studie MeSH
• RNA-polymerasa III genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• DNA řízené RNA-polymerasy MeSH
• POLR1C protein, human MeSH Prohlížeč
• POLR3A protein, human MeSH Prohlížeč
• POLR3B protein, human MeSH Prohlížeč
• RNA-polymerasa III MeSH

In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.

• Klíčová slova
• DENN, HSAN, intellectual disability, multisystem, whole-exome sequencing,
• MeSH
• fenotyp MeSH
• lidé MeSH
• mutace MeSH
• nemoci nervového systému genetika   MeSH
• signální adaptorové proteiny receptorové domény smrti genetika   MeSH
• signální transdukce genetika   MeSH
• transport proteinů genetika   MeSH
• výměnné faktory guaninnukleotidů genetika   MeSH
• vývojové poruchy u dětí genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• MADD protein, human MeSH Prohlížeč
• signální adaptorové proteiny receptorové domény smrti MeSH
• výměnné faktory guaninnukleotidů MeSH

3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMGCLD) is a rare inborn error of ketone body synthesis and leucine degradation, caused by mutations in the HMGCL gene. In order to obtain a comprehensive view on this disease, we have collected clinical and biochemical data as well as information on HMGCL mutations of 37 patients (35 families) from metabolic centers in Belgium, Germany, The Netherlands, Switzerland, and Turkey. All patients were symptomatic at some stage with 94% presenting with an acute metabolic decompensation. In 50% of the patients, the disorder manifested neonatally, mostly within the first days of life. Only 8% of patients presented after one year of age. Six patients died prior to data collection. Long-term neurological complications were common. Half of the patients had a normal cognitive development while the remainder showed psychomotor deficits. We identified seven novel HMGCL mutations. In agreement with previous reports, no clear genotype-phenotype correlation could be found. This is the largest cohort of HMGCLD patients reported so far, demonstrating that HMGCLD is a potentially life-threatening disease with variable clinical outcome. Our findings suggest that the clinical course of HMGCLD cannot be predicted accurately from HMGCL genotype. The overall outcome in HMGCLD appears limited, thus rendering early diagnosis and strict avoidance of metabolic crises important.

• Klíčová slova
• Enzyme activity, Fatty acid metabolism, Ketogenesis, Ketone body synthesis, Leucine degradation, Organic aciduria,
• MeSH
• acetyl-CoA-C-acetyltransferasa nedostatek   MeSH
• dítě MeSH
• dospělí MeSH
• genetické asociační studie MeSH
• hodnocení výsledků pacienta MeSH
• ketolátky metabolismus   MeSH
• kojenec MeSH
• leucin metabolismus   MeSH
• lidé MeSH
• lyasy oxokyselin genetika   MeSH
• mastné kyseliny metabolismus   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace MeSH
• předškolní dítě MeSH
• vrozené poruchy metabolismu aminokyselin * komplikace   diagnóza   dietoterapie   patofyziologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• Geografické názvy
• Belgie MeSH
• Německo MeSH
• Nizozemsko MeSH
• Švýcarsko MeSH
• Turecko MeSH
• Názvy látek
• 3-hydroxy-3-methylglutaryl-coenzyme A lyase MeSH Prohlížeč
• acetyl-CoA-C-acetyltransferasa MeSH
• ketolátky MeSH
• leucin MeSH
• lyasy oxokyselin MeSH
• mastné kyseliny MeSH