Rett spectrum disorder is a progressive neurological disease and the most common genetic cause of intellectual disability in females. MECP2 is the major causative gene. In addition, CDKL5 and FOXG1 mutations have been reported in Rett patients, especially with the atypical presentation. Each gene and different mutations within each gene contribute to variability in clinical presentation, and several groups worldwide performed genotype-phenotype correlation studies using cohorts of patients with classic and atypical forms of Rett spectrum disorder. The Rett Networked Database is a unified registry of clinical and molecular data of Rett patients, and it is currently one of the largest Rett registries worldwide with several hundred records provided by Rett expert clinicians from 13 countries. Collected data revealed that the majority of MECP2-mutated patients present with the classic form, the majority of CDKL5-mutated patients with the early-onset seizure variant, and the majority of FOXG1-mutated patients with the congenital form. A computation of severity scores further revealed significant differences between groups of patients and correlation with mutation types. The highly detailed phenotypic information contained in the Rett Networked Database allows the grouping of patients presenting specific clinical and genetic characteristics for studies by the Rett community and beyond. These data will also serve for the development of clinical trials involving homogeneous groups of patients.

Sarcoglycanopathies include four subtypes of autosomal recessive limb-girdle muscular dystrophies (LGMDR3, LGMDR4, LGMDR5 and LGMDR6) that are caused, respectively, by mutations in the SGCA, SGCB, SGCG and SGCD genes. Delta-sarcoglycanopathy (LGMDR6) is the least frequent and is considered an ultra-rare disease. Our aim was to characterize the clinical and genetic spectrum of a large international cohort of LGMDR6 patients and to investigate whether or not genetic or protein expression data could predict a disease’s severity. This is a retrospective study collecting demographic, genetic, clinical and histological data of patients with genetically confirmed LGMDR6 including protein expression data from muscle biopsies. We contacted 128 paediatric and adult neuromuscular units around the world that reviewed genetic data of patients with a clinical diagnosis of a neuromuscular disorder. We identified 30 patients with a confirmed diagnosis of LGMDR6 of which 23 patients were included in this study. Eighty-seven per cent of the patients had consanguineous parents. Ninety-one per cent of the patients were symptomatic at the time of the analysis. Proximal muscle weakness of the upper and lower limbs was the most common presenting symptom. Distal muscle weakness was observed early over the course of the disease in 56.5% of the patients. Cardiac involvement was reported in five patients (21.7%) and four patients (17.4%) required non-invasive ventilation. Sixty per cent of patients were wheelchair-bound since early teens (median age of 12.0 years). Patients with absent expression of the sarcoglycan complex on muscle biopsy had a significant earlier onset of symptoms and an earlier age of loss of ambulation compared to patients with residual protein expression. This study confirmed that delta-sarcoglycanopathy is an ultra-rare neuromuscular condition and described the clinical and molecular characteristics of the largest yet-reported collected cohort of patients. Our results showed that this is a very severe and quickly progressive disease characterized by generalized muscle weakness affecting predominantly proximal and distal muscles of the limbs. Similar to other forms of sarcoglycanopathies, the severity and rate of progressive weakness correlates inversely with the abundance of protein on muscle biopsy.

Tuberous sclerosis complex (TSC) is a multisystem disorder characterized by seizures, neuropsychiatric disorders, and tumors of the heart, brain, skin, lungs, and kidneys. We present a three-year follow-up of a patient with TSC-associated rhabdomyoma detected in utero. Genetic examination of the fetus and the parents revealed a de novo variant in the TSC2 gene (c.3037delG, p.Asp1013IlefsTer3). Oral everolimus was initiated in the pregnant mother to regress the fetal tumor, which was successful. To the best of our knowledge, there is very little information regarding the use of everolimus therapy during pregnancy. West-syndrome was diagnosed when the proband was four months old. The symptoms were well-manageable, however temporarily. Therapy-resistant focal seizures were frequent. The patient had good vitals and was under regular cardiological control, showed a balanced circulation, and did not require any medication. Subependymal giant cell astrocytoma (SEGA) identified by regular neuroimaging examinations remained unchanged, which may be a consequence of early intrauterine treatment. Early detection of the pathogenic TSC2 variant, followed by in utero administration of everolimus and early vigabatrin therapy, allowed the detection of a milder developmental delay of the proband. Our study emphasizes how early genetic testing and management of epilepsy are pivotal for proper neurodevelopmental impacts and therapeutic strategies.

Kleefstra syndrome is a rare genetic disorder, with core phenotypic features encompassing developmental delay/intellectual disability, characteristic facial features – brachy(micro)cephaly, unusual shaped eyebrows, flat face with hypertelorism, short nose with anteverted nostrils, thickened lower lip, carpmouth with macroglossia - and childhood hypotonia. Some additional symptoms are observed in different percentage of the patients. Epilepsy is common symptom as well. The underlying cause of the syndrome is a submicroscopic deletion in the chromosomal region 9q34.3 or disruption of the euchromatin histone methyl transferase 1. We describe two Hungarian Kleefstra syndrome patients, one with the classic phenotype of the syndrome, the diagnosis was confirmed by subtelomeric FISH. Meanwhile in our second patient beside the classic phenotype a new symptom – abnormal antiepileptic drug metabolic response – could be observed. Subtelomere FISH confirmed the 9q34.3 terminal deletion. Because of the abnormal drug metabolism in our second patient, we performed array CGH analysis as well searching for other rearrangements. Array CGH analysis indicated a large – 1.211 Mb -, deletion only in the 9q subtelomeric region with breakpoints ch9:139,641,471-140,852,911. This is the first report on Kleefstra syndrome in patients describing a classical and a complex phenotype involving altered drug metabolism.

The 4q deletion syndrome shows a broad spectrum of clinical manifestations consisting of key features comprising growth failure, developmental delay, craniofacial dysmorphism, digital anomalies, and cardiac and skeletal defects. We have identified a de novo interstitial distal deletion in a 9 month-old girl with growth failure, developmental delay, ventricular septum defect in the subaortic region, patent foramen ovale and patent ductus arteriosus, vascular malformation of the lung, dysgenesis of the corpus callosum and craniofacial dysmorphism using array-comparative genomic hybridization. This de novo deletion is located at 4q28.3-31.23 (136,127,048 - 150,690,325), its size is 14.56 Mb, and contains 8 relevant genes (PCDH18, SETD7, ELMOD2, IL15, GAB1, HHIP, SMAD1, NR3C2) with possible contributions to the phenotype. Among other functions, a role in lung morphogenesis and tubulogenesis can be attributed to the deleted genes in our patient, which may explain the unique feature of vascular malformation of the lung leading to pulmonary hypertension. With the detailed molecular characterization of our case with 4q- syndrome we hope to contribute to the elucidation of the genetic spectrum of this disorder.

Background: Facial angiofibromas (FAs) are a major feature of tuberous sclerosis complex (TSC). Topical rapamycin can successfully treat FAs. A new stabilized cream formulation that protects rapamycin from oxidation has been developed in 0.5% and 1% concentrations. Objectives: To assess the efficacy and safety of a novel, stabilized topical rapamycin cream formulation. Methods: This multicentre double-blind randomized placebo-controlled dose–response phase II/III study with a parallel design included participants aged 6–65 years with FAs of mild or moderate severity according to the Investigator’s Global Assessment (IGA) scale. Participants were randomized to one of three treatment arms: topical rapamycin 0.5%, topical rapamycin 1% or placebo. Treatment was applied once daily for 26 weeks. Safety and efficacy measures were assessed at days 14, 56, 98, 140 and 182. The primary endpoint was the percentage of participants achieving IGA scores of ‘clear’ or ‘almost clear’ after 26 weeks of treatment. Secondary measures included Facial Angiofibroma Severity Index (FASI) and participant- and clinician-reported percentage-based improvement. Safety measures included the incidence of treatment-emergent adverse events and blood rapamycin concentration changes over time. Results: Participants (n = 107) were randomized to receive either rapamycin 1% (n = 33), rapamycin 0.5% (n = 36) or placebo (n = 38). All treated participants were included in the final analysis. The percentage of participants with a two-grade IGA improvement was greater in the rapamycin 0.5% treatment group (11%) and rapamycin 1% group (9%) than in the placebo group (5%). However, this was not statistically significant [rapamycin 0.5%: odds ratio (OR) 1.71, 95% confidence interval (CI) 0.36–8.18 (P = 0.50); rapamycin 1%: OR 1.68, 95% CI 0.33–8.40 (P = 0.53)]. There was a statistically significant difference in the proportion of participants treated with rapamycin cream that achieved at least a one-grade improvement in IGA [rapamycin 0.5%: 56% (OR 4.73, 95% CI 1.59–14.10; P = 0.005); rapamycin 1%: 61% (OR 5.14, 95% CI 1.70–15.57; P = 0.004); placebo: 24%]. Skin adverse reactions were more common in patients following rapamycin application (64%) vs. placebo (29%). Conclusions: Both rapamycin cream formulations (0.5% and 1%) were well tolerated, and either strength could lead to clinical benefit in the treatment of FA.