Adult phenotype in Koolen-de Vries/KANSL1 haploinsufficiency syndrome.

BACKGROUND: Koolen-de Vries syndrome (KdVS) is a multisystem neurodevelopmental disorder caused by 17q21.31 deletions or mutations in KANSL1. It was mainly described in children. METHODS: A retrospective study on 9 subjects aged 19-45 years and revision of 18 literature patients, with the purpose to get insights into the phenotypic evolution with time, and into the clinical manifestations in adulthood. RESULTS: Seven patients had a 17q21.31 deletion and two a point mutation in KANSL1. All had intellectual disability, which was mild in five (56%) and moderate in four (44%). Epilepsy was diagnosed in four subjects (44%), with onset from 1 to 7 years and full remission before 9 years in 3/4 patients. Scoliosis affected seven individuals (77.7%) and it was substantially stable with age in 5/7 patients, allowing for simple daily activities. Two subjects had severely progressive scoliosis, which was surgically corrected. Overweight or true obesity did occur after puberty in six patients (67%). Behaviour abnormalities were recorded in six patients (67%). The facial phenotype slightly evolved with time to include thick eyebrows, elongated nose and pronounced pointed chin. Despite behaviour abnormalities, happy disposition and sociable attitudes were common. Half of patients had fluent language and were good at writing and reading. Rich language, although limited to single words or short sentences, and very limited or absent skills in writing and reading were observed in the remaining patients. Autonomy in daily activities and personal care was usually limited. CONCLUSIONS: Distinctive features in adult KdVS subjects include intellectual disability, overweight/obesity, behaviour abnormalities with preserved social interest, ability in language, slight worsening of the facial phenotype and no seizures.

Endocrinological manifestations in RASopathies.

The evaluation of endocrine involvement in RASopathies is important for the care and follow-up of patients affected by these conditions. Short stature is a cardinal feature of RASopathies and correlates with multiple factors. Growth hormone treatment is a therapeutic possibility to improve height and quality of life. Assessment of growth rate and growth laboratory parameters is routine, but age at start of therapy, dose and effects of growth hormone on final height need to be clarified. Puberty disorders and gonadal dysfunction, in particular in males, are other endocrinological areas to evaluate for their effects on growth and development. Thyroid dysfunction, autoimmune disease and bone involvement have also been reported in RASopathies. In this brief review, we describe the current knowledge on growth, growth hormone therapy, endocrinological involvement in patients affected by RASopathies.

The Discovery of a LEMD2-Associated Nuclear Envelopathy with Early Progeroid Appearance Suggests Advanced Applications for AI-Driven Facial Phenotyping.

Over a relatively short period of time, the clinical geneticist's "toolbox" has been expanded by machine-learning algorithms for image analysis, which can be applied to the task of syndrome identification on the basis of facial photographs, but these technologies harbor potential beyond the recognition of established phenotypes. Here, we comprehensively characterized two individuals with a hitherto unknown genetic disorder caused by the same de novo mutation in LEMD2 (c.1436C>T;p.Ser479Phe), the gene which encodes the nuclear envelope protein LEM domain-containing protein 2 (LEMD2). Despite different ages and ethnic backgrounds, both individuals share a progeria-like facial phenotype and a distinct combination of physical and neurologic anomalies, such as growth retardation; hypoplastic jaws crowded with multiple supernumerary, yet unerupted, teeth; and cerebellar intention tremor. Immunofluorescence analyses of patient fibroblasts revealed mutation-induced disturbance of nuclear architecture, recapitulating previously published data in LEMD2-deficient cell lines, and additional experiments suggested mislocalization of mutant LEMD2 protein within the nuclear lamina. Computational analysis of facial features with two different deep neural networks showed phenotypic proximity to other nuclear envelopathies. One of the algorithms, when trained to recognize syndromic similarity (rather than specific syndromes) in an unsupervised approach, clustered both individuals closely together, providing hypothesis-free hints for a common genetic etiology. We show that a recurrent de novo mutation in LEMD2 causes a nuclear envelopathy whose prognosis in adolescence is relatively good in comparison to that of classical Hutchinson-Gilford progeria syndrome, and we suggest that the application of artificial intelligence to the analysis of patient images can facilitate the discovery of new genetic disorders.

Chondrodysplasia and growth failure in children after early hematopoietic stem cell transplantation for non-oncologic disorders.

Bone dysplasias (osteochondrodysplasias) are a large group of conditions associated with short stature, skeletal disproportion, and radiographic abnormalities of skeletal elements. Nearly all are genetic in origin. We report a series of seven children with similar findings of chondrodysplasia and growth failure following early hematopoietic stem cell transplantation (HSCT) for pediatric non-oncologic disease: hemophagocytic lymphohistiocytosis or HLH (five children, three with biallelic HLH-associated variants [in PRF1 and UNC13D] and one with HLH secondary to visceral Leishmaniasis), one child with severe combined immunodeficiency and one with Omenn syndrome (both children had biallelic RAG1 pathogenic variants). All children had normal growth and no sign of chondrodysplasia at birth and prior to their primary disease. After HSCT, all children developed growth failure, with standard deviation scores for height at or below -3. Radiographically, all children had changes in the spine, metaphyses and epiphyses, compatible with a spondyloepimetaphyseal dysplasia. Genomic sequencing failed to detect pathogenic variants in genes associated with osteochondrodysplasias. We propose that such chondrodysplasia with growth failure is a novel, rare, but clinically important complication following early HSCT for non-oncologic pediatric diseases. The pathogenesis is unknown but could possibly involve loss or perturbation of the cartilage-bone stem cell population.

Delineation of phenotypes and genotypes related to cohesin structural protein RAD21.

RAD21 encodes a key component of the cohesin complex, and variants in RAD21 have been associated with Cornelia de Lange Syndrome (CdLS). Limited information on phenotypes attributable to RAD21 variants and genotype-phenotype relationships is currently published. We gathered a series of 49 individuals from 33 families with RAD21 alterations [24 different intragenic sequence variants (2 recurrent), 7 unique microdeletions], including 24 hitherto unpublished cases. We evaluated consequences of 12 intragenic variants by protein modelling and molecular dynamic studies. Full clinical information was available for 29 individuals. Their phenotype is an attenuated CdLS phenotype compared to that caused by variants in NIPBL or SMC1A for facial morphology, limb anomalies, and especially for cognition and behavior. In the 20 individuals with limited clinical information, additional phenotypes include Mungan syndrome (in patients with biallelic variants) and holoprosencephaly, with or without CdLS characteristics. We describe several additional cases with phenotypes including sclerocornea, in which involvement of the RAD21 variant is uncertain. Variants were frequently familial, and genotype-phenotype analyses demonstrated striking interfamilial and intrafamilial variability. Careful phenotyping is essential in interpreting consequences of RAD21 variants, and protein modeling and dynamics can be helpful in determining pathogenicity. The current study should be helpful when counseling families with a RAD21 variation.

A novel mutation in SPART gene causes a severe neurodevelopmental delay due to mitochondrial dysfunction with complex I impairments and altered pyruvate metabolism.

Loss-of-function mutations in the SPART gene cause Troyer syndrome, a recessive form of spastic paraplegia resulting in muscle weakness, short stature, and cognitive defects. SPART encodes for Spartin, a protein linked to endosomal trafficking and mitochondrial membrane potential maintenance. Here, we identified with whole exome sequencing (WES) a novel frameshift mutation in the SPART gene in 2 brothers presenting an uncharacterized developmental delay and short stature. Functional characterization in an SH-SY5Y cell model shows that this mutation is associated with increased neurite outgrowth. These cells also show a marked decrease in mitochondrial complex I (NADH dehydrogenase) activity, coupled to decreased ATP synthesis and defective mitochondrial membrane potential. The cells also presented an increase in reactive oxygen species, extracellular pyruvate, and NADH levels, consistent with impaired complex I activity. In concordance with a severe mitochondrial failure, Spartin loss also led to an altered intracellular Ca2+ homeostasis that was restored after transient expression of wild-type Spartin. Our data provide for the first time a thorough assessment of Spartin loss effects, including impaired complex I activity coupled to increased extracellular pyruvate. In summary, through a WES study we assign a diagnosis of Troyer syndrome to otherwise undiagnosed patients, and by functional characterization we show that the novel mutation in SPART leads to a profound bioenergetic imbalance.-Diquigiovanni, C., Bergamini, C., Diaz, R., Liparulo, I., Bianco, F., Masin, L., Baldassarro, V. A., Rizzardi, N., Tranchina, A., Buscherini, F., Wischmeijer, A., Pippucci, T., Scarano, E., Cordelli, D. M., Fato, R., Seri, M., Paracchini, S., Bonora, E. A novel mutation in SPART gene causes a severe neurodevelopmental delay due to mitochondrial dysfunction with complex I impairments and altered pyruvate metabolism.

HDAC8 Loss of Function and SHOX Haploinsufficiency: Two Independent Genetic Defects Responsible for a Complex Phenotype.

We report a patient with developmental delay, brachydactyly type E, short stature, and tetralogy of Fallot. Brachydactyly-mental retardation syndrome (BDMR) was suspected based on the phenotype; however, array CGH excluded a 2q37 deletion, but identified a deletion encompassing the SHOX gene. BDMR is characterized by cognitive impairment, skeletal abnormalities involving hands and feet, short stature, and overweight. Most affected individuals carry relatively large 2q37 deletions encompassing HDAC4. This gene encodes a histone deacetylase involved in epigenetic regulation of cell growth and differentiation, specifically during endochondral bone formation in chondrocyte hypertrophy. Since SHOX haploinsufficiency can cause skeletal defects and short stature but would not fully explain the clinical picture of this patient, exome sequencing was performed, and a heterozygous HDAC8 frameshift mutation was identified. HDAC8 is a distinct histone deacetylase involved in cohesin recycling and is responsible for an X-linked dominant Cornelia de Lange-like phenotype. A new blended clinical phenotype may be explained by the result of a dual molecular diagnosis, which represents a combination of 2 independent genetic defects, with relevant implications for genetic counseling, clinical management, and prognosis.

Anthropometric characteristics of newborns with Prader-Willi syndrome.

This is a retrospective multicenter nationwide Italian study collecting neonatal anthropometric data of Caucasian subjects with Prader-Willi syndrome (PWS) born from 1988 to 2018. The aim of the study is to provide percentile charts for weight and length of singletons with PWS born between 36 and 42 gestational weeks. We collected the birth weight and birth length of 252 male and 244 female singleton live born infants with both parents of Italian origin and PWS genetically confirmed. Percentile smoothed curves of birth weight and length for gestational age were built through Cole's lambda, mu, sigma method. The data were compared to normal Italian standards. Newborns with PWS showed a lower mean birth weight, by 1/2 kg, and a shorter mean birth length, by 1 cm, than healthy neonates. Females with a 15q11-13 deletion were shorter than those with maternal uniparental maternal disomy of chromosome 15 (p < .0001). The present growth curves may be useful as further traits in supporting a suspicion of PWS in a newborn. Because impaired prenatal growth increases risk of health problems later in life, having neonatal anthropometric standards could be helpful to evaluate possible correlations between the presence or absence of small gestational age and some clinical and metabolic aspects of PWS.

From Whole Gene Deletion to Point Mutations of EP300-Positive Rubinstein-Taybi Patients: New Insights into the Mutational Spectrum and Peculiar Clinical Hallmarks.

Rubinstein-Taybi syndrome (RSTS) is a rare congenital neurodevelopmental disorder characterized by growth deficiency, skeletal abnormalities, dysmorphic features, and intellectual disability. Causative mutations in CREBBP and EP300 genes have been identified in ∼55% and ∼8% of affected individuals. To date, only 28 EP300 alterations in 29 RSTS clinically described patients have been reported. EP300 analysis of 22 CREBBP-negative RSTS patients from our cohort led us to identify six novel mutations: a 376-kb deletion depleting EP300 gene; an exons 17-19 deletion (c.(3141+1_3142-1)_(3590+1_3591-1)del/p.(Ile1047Serfs*30)); two stop mutations, (c.3829A>T/p.(Lys1277*) and c.4585C>T/p.(Arg1529*)); a splicing mutation (c.1878-12A>G/p.(Ala627Glnfs*11)), and a duplication (c.4640dupA/p.(Asn1547Lysfs*3)). All EP300-mutated individuals show a mild RSTS phenotype and peculiar findings including maternal gestosis, skin manifestation, especially nevi or keloids, back malformations, and a behavior predisposing to anxiety. Furthermore, the patient carrying the complete EP300 deletion does not show a markedly severe clinical picture, even if a more composite phenotype was noticed. By characterizing six novel EP300-mutated patients, this study provides further insights into the EP300-specific clinical presentation and expands the mutational repertoire including the first case of a whole gene deletion. These new data will enhance EP300-mutated cases identification highlighting distinctive features and will improve the clinical practice allowing a better genotype-phenotype correlation.

Response to long-term growth hormone therapy in patients affected by RASopathies and growth hormone deficiency: Patterns of growth, puberty and final height data.

RASopathies are developmental disorders caused by heterozygous germline mutations in genes encoding proteins in the RAS-MAPK signaling pathway. Reduced growth is a common feature. Several studies generated data on growth, final height (FH), and height velocity (HV) after growth hormone (GH) treatment in patients with these disorders, particularly in Noonan syndrome, the most common RASopathy. These studies, however, refer to heterogeneous cohorts in terms of molecular information, GH status, age at start and length of therapy, and GH dosage. This work reports growth data in 88 patients affected by RASopathies with molecularly confirmed diagnosis, together with statistics on body proportions, pubertal pattern, and FH in 33, including 16 treated with GH therapy for proven GH deficiency. Thirty-three patients showed GH deficiency after pharmacological tests, and were GH-treated for an average period of 6.8 ± 4.8 years. Before starting therapy, HV was -2.6 ± 1.3 SDS, and mean basal IGF1 levels were -2.0 ± 1.1 SDS. Long-term GH therapy, starting early during childhood, resulted in a positive height response compared with untreated patients (1.3 SDS in terms of height-gain), normalizing FH for Ranke standards but not for general population and Target Height. Pubertal timing negatively affected pubertal growth spurt and FH, with IGF1 standardized score increased from -2.43 to -0.27 SDS. During GH treatment, no significant change in bone age velocity, body proportions, or cardiovascular function was observed.

Loss-of-function variants in ERF are associated with a Noonan syndrome-like phenotype with or without craniosynostosis.

Pathogenic, largely truncating variants in the ETS2 repressor factor (ERF) gene, encoding a transcriptional regulator negatively controlling RAS-MAPK signaling, have been associated with syndromic craniosynostosis involving various cranial sutures and Chitayat syndrome, an ultrarare condition with respiratory distress, skeletal anomalies, and facial dysmorphism. Recently, a single patient with craniosynostosis and a phenotype resembling Noonan syndrome (NS), the most common disorder among the RASopathies, was reported to carry a de novo loss-of-function variant in ERF. Here, we clinically profile 26 individuals from 15 unrelated families carrying different germline heterozygous variants in ERF and showing a phenotype reminiscent of NS. The majority of subjects presented with a variable degree of global developmental and/or language delay. Their shared facial features included absolute/relative macrocephaly, high forehead, hypertelorism, palpebral ptosis, wide nasal bridge, and low-set/posteriorly angulated ears. Stature was below the 3rd centile in two-third of the individuals, while no subject showed typical NS cardiac involvement. Notably, craniosynostosis was documented only in three unrelated individuals, while a dolichocephalic aspect of the skull in absence of any other evidence supporting a premature closing of sutures was observed in other 10 subjects. Unilateral Wilms tumor was diagnosed in one individual. Most cases were familial, indicating an overall low impact on fitness. Variants were nonsense and frameshift changes, supporting ERF haploinsufficiency. These findings provide evidence that heterozygous loss-of-function variants in ERF cause a "RASopathy" resembling NS with or without craniosynostosis, and allow a first dissection of the molecular circuits contributing to MAPK signaling pleiotropy.

Endocrine features of Prader-Willi syndrome: a narrative review focusing on genotype-phenotype correlation.

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by three different types of molecular genetic abnormalities. The most common defect is a deletion on the paternal 15q11-q13 chromosome, which is seen in about 60% of individuals. The next most common abnormality is maternal disomy 15, found in around 35% of cases, and a defect in the imprinting center that controls the activity of certain genes on chromosome 15, seen in 1-3% of cases. Individuals with PWS typically experience issues with the hypothalamic-pituitary axis, leading to excessive hunger (hyperphagia), severe obesity, various endocrine disorders, and intellectual disability. Differences in physical and behavioral characteristics between patients with PWS due to deletion versus those with maternal disomy are discussed in literature. Patients with maternal disomy tend to have more frequent neurodevelopmental problems, such as autistic traits and behavioral issues, and generally have higher IQ levels compared to those with deletion of the critical PWS region. This has led us to review the pertinent literature to investigate the possibility of establishing connections between the genetic abnormalities and the endocrine disorders experienced by PWS patients, in order to develop more targeted diagnostic and treatment protocols. In this review, we will review the current state of clinical studies focusing on endocrine disorders in individuals with PWS patients, with a specific focus on the various genetic causes. We will look at topics such as neonatal anthropometry, thyroid issues, adrenal problems, hypogonadism, bone metabolism abnormalities, metabolic syndrome resulting from severe obesity caused by hyperphagia, deficiencies in the GH/IGF-1 axis, and the corresponding responses to treatment.

GH Therapy and first final height data in Noonan-like syndrome with loose anagen hair (Mazzanti syndrome).

Noonan-like syndrome with loose anagen hair (NS/LAH or Mazzanti Syndrome) is caused by a single missense mutation in SHOC2 promoting tN-myristoylation of the encoded protein. Cardinal features include facial features resembling NS, short stature often associated with proven growth hormone deficiency (GHD), typical ectodermal anomalies, and distinctive behavior. Overall, the clinical features are more severe than those generally observed in NS, even though the phenotype improves with age. We report on growth and pubertal trend in seven patients heterozygous for a mutated SHOC2 allele, treated with long-term GH-therapy, and final height (FH) in three of them. They were approximately -3 SDS below the Italian general population standards, they had very low IGF1 levels at baseline and GHD at pharmacological tests. All patients were treated with GH (0.035 mg/kg/day) for a mean period of 8.49 ± 5.72 years. After the 1st year of GH-therapy, IGF1 level and height velocity had increased. Three of 7 patients reached the FH (-2.34 ± 0.12 SDS) at 18.25 ± 0.73 years, after GH administration for 12.39 ± 2.12 years. Pubertal development was variable, showing a prolonged and delayed puberty or rapid pubertal progression that could impair the FH. Overall, our data in this small cohort suggest that NS/LAH patients benefit from long-term GH-therapy, although they do not show the characteristic catch-up growth of isolated GHD. While the observed growth and pubertal behavior is consistent with a dysfunction of the hypothalamic-pituitary-gonadal axis, the functional link between SHOC2 and the GH/IGF signaling pathways remains to be clarified.

Chromosomal Microarray Analysis Identifies a Novel SALL1 Deletion, Supporting the Association of Haploinsufficiency with a Mild Phenotype of Townes-Brocks Syndrome.

SALL1 heterozygous pathogenic variants cause Townes-Brocks syndrome (TBS), a condition with variable clinical presentation. The main features are a stenotic or imperforate anus, dysplastic ears, and thumb malformations, and other common concerns are hearing impairments, foot malformations, and renal and heart defects. Most of the pathogenic SALL1 variants are nonsense and frameshift, likely escaping nonsense-mediated mRNA decay and causing disease via a dominant-negative mechanism. Haploinsufficiency may result in mild phenotypes, but only four families with distinct SALL1 deletions have been reported to date, with a few more being of larger size and also affecting neighboring genes. We report on a family with autosomal dominant hearing impairment and mild anal and skeletal anomalies, in whom a novel 350 kb SALL1 deletion, spanning exon 1 and the upstream region, was identified by array comparative genomic hybridization. We review the clinical findings of known individuals with SALL1 deletions and point out that the overall phenotype is milder, especially when compared with individuals who carry the recurrent p.Arg276Ter mutation, but with a possible higher risk of developmental delay. Chromosomal microarray analysis is still a valuable tool in the identification of atypical/mild TBS cases, which are likely underestimated.

Lipid profile in Noonan syndrome and related disorders: trend by age, sex and genotype.

Background: RASopathies are developmental disorders caused by dysregulation of the RAS-MAPK signalling pathway, which contributes to the modulation of multiple extracellular signals, including hormones and growth factors regulating energetic metabolism, including lipid synthesis, storage, and degradation. Subjects and methods: We evaluated the body composition and lipid profiles of a single-centre cohort of 93 patients with a molecularly confirmed diagnosis of RASopathy by assessing height, BMI, and total cholesterol, HDL, triglycerides, apolipoprotein, fasting glucose, and insulin levels, in the context of a cross sectional and longitudinal study. We specifically investigated and compared anthropometric and haematochemistry data between the Noonan syndrome (NS) and Mazzanti syndrome (NS/LAH) groups. Results: At the first evaluation (9.5 ± 6.2 years), reduced growth (-1.80 ± 1.07 DS) was associated with a slightly reduced BMI (-0.34 DS ± 1.15 DS). Lipid profiling documented low total cholesterol levels (< 5th percentile) in 42.2% of the NS group; in particular, in 48.9% of PTPN11 patients and in 28.6% of NS/LAH patients compared to the general population, with a significant difference between males and females. A high proportion of patients had HDL levels lower than the 26th percentile, when compared to the age- and sex-matched general population. Triglycerides showed an increasing trend with age only in NS females. Genotype-phenotype correlations were also evident, with particularly reduced total cholesterol in about 50% of patients with PTPN11 mutations with LDL-C and HDL-C tending to decrease during puberty. Similarly, apolipoprotein A1 and apolipoprotein B deficits were documented, with differences in prevalence associated with the genotype for apolipoprotein A1. Fasting glucose levels and HOMA-IR were within the normal range. Conclusion: The present findings document an unfavourable lipid profile in subjects with NS, in particular PTPN11 mutated patients, and NS/LAH. Further studies are required to delineate the dysregulation of lipid metabolism in RASopathies more systematically and confirm the occurrence of previously unappreciated genotype-phenotype correlations involving the metabolic profile of these disorders.

Real-life long-term efficacy and safety of recombinant human growth hormone therapy in children with short stature homeobox-containing deficiency.

Objective: This Italian survey aims to evaluate real-life long-term efficacy and safety of recombinant human growth hormone (rhGH) therapy in children with short stature homeobox-containing gene deficiency disorders (SHOX-D) and to identify potential predictive factors influencing response to rhGH therapy. Design and methods: This is a national retrospective observational study collecting anamnestic, anthropometric, clinical, instrumental and therapeutic data in children and adolescents with a genetic confirmation of SHOX-D treated on rhGH. Data were collected at the beginning of rhGH therapy (T0), yearly during the first 4 years of rhGH therapy (T1, T2, T3 and T4) and at near-final height (nFH) (T5), when available. Results: One hundred and seventeen SHOX-D children started rhGH therapy (initial dose 0.23 ± 0.04 mg/kg/week) at a mean age of 8.67 ± 3.33 years (74% prepubertal), 99 completed the first year of treatment and 46 reached nFH. During rhGH therapy, growth velocity (GV), standard deviation score (SDS) and height (H) SDS improved significantly. Mean H SDS gain from T0 was +1.14 ± 0.58 at T4 and +0.80 ± 0.98 at T5. Both patients carrying mutations involving intragenic SHOX region (group A) and ones with regulatory region defects (group B) experienced a similar beneficial therapeutic effect. The multiple regression analysis identified the age at the start of rhGH treatment (ß = -0.31, P = 0.030) and the GV during the first year of rhGH treatment (ß = 0.45, P = 0.008) as main independent predictor factors of height gain. During rhGH therapy, no adverse event of concern was reported. Conclusions: Our data confirm the efficacy and safety of rhGH therapy in SHOX-D children, regardless the wide variety of genotype. Significance Statement: Among children with idiopathic short stature, the prevalence of SHOX-D is near to 1/1000-2000 (1.1-15%) with a wide phenotypic spectrum. Current guidelines support rhGH therapy in SHOX-D children, but long-term data are still few. Our real-life data confirm the efficacy and safety of rhGH therapy in SHOX-D children, regardless of the wide variety of genotypes. Moreover, rhGH therapy seems to blunt the SHOX-D phenotype. The response to rhGH in the first year of treatment and the age when rhGH was started significantly impact the height gain.

Epilepsy is an important feature of KBG syndrome associated with poorer developmental outcome.

OBJECTIVE: The aim of this study was to describe the epilepsy phenotype in a large international cohort of patients with KBG syndrome and to study a possible genotype-phenotype correlation. METHODS: We collected data on patients with ANKRD11 variants by contacting University Medical Centers in the Netherlands, an international network of collaborating clinicians, and study groups who previously published about KBG syndrome. All patients with a likely pathogenic or pathogenic ANKRD11 variant were included in our patient cohort and categorized into an "epilepsy group" or "non-epilepsy group". Additionally, we included previously reported patients with (likely) pathogenic ANKRD11 variants and epilepsy from the literature. RESULTS: We included 75 patients with KBG syndrome of whom 26 had epilepsy. Those with epilepsy more often had moderate to severe intellectual disability (42.3% vs 9.1%, RR 4.6 [95% CI 1.7-13.1]). Seizure onset in patients with KBG syndrome occurred at a median age of 4 years (range 12 months - 20 years), and the majority had generalized onset seizures (57.7%) with tonic-clonic seizures being most common (23.1%). The epilepsy type was mostly classified as generalized (42.9%) or combined generalized and focal (42.9%), not fulfilling the criteria of an electroclinical syndrome diagnosis. Half of the epilepsy patients (50.0%) were seizure free on anti-seizure medication (ASM) for at least 1 year at the time of last assessment, but 26.9% of patients had drug-resistant epilepsy (failure of ≥2 ASM). No genotype-phenotype correlation could be identified for the presence of epilepsy or epilepsy characteristics. SIGNIFICANCE: Epilepsy in KBG syndrome most often presents as a generalized or combined focal and generalized type. No distinctive epilepsy syndrome could be identified. Patients with KBG syndrome and epilepsy had a significantly poorer neurodevelopmental outcome compared with those without epilepsy. Clinicians should consider KBG syndrome as a causal etiology of epilepsy and be aware of the poorer neurodevelopmental outcome in individuals with epilepsy.

Clinical and molecular description of the first Italian cohort of 33 subjects with hypophosphatasia.

Introduction: Hypophosphatasia (HPP) is a rare genetic disease caused by inactivating variants of the ALPL gene. Few data are available on the clinical presentation in Italy and/or on Italian HPP surveys. Methods: There were 30 suspected HPP patients recruited from different Italian tertiary cares. Biological samples and related clinical, biochemical, and anamnestic data were collected and the ALPL gene sequenced. Search for large genomic deletions at the ALPL locus (1p36) was done. Phylogenetic conservation and modeling were applied to infer the effect of the variants on the protein structure. Results: There were 21 ALPL variants and one large genomic deletion found in 20 out of 30 patients. Unexpectedly, NGS-driven differential diagnosis allowed uncovering three hidden additional HPP cases, for a total of 33 HPP subjects. Eight out of 24 coding variants were novel and classified as "pathogenic", "likely pathogenic", and "variants of uncertain significance". Bioinformatic analysis confirmed that all the variants strongly destabilize the homodimer structure. There were 10 cases with low ALP and high VitB6 that resulted negative to genetic testing, whereas two positive cases have an unexpected normal ALP value. No association was evident with other biochemical/clinical parameters. Discussion: We present the survey of HPP Italian patients with the highest ALPL mutation rate so far reported and confirm the complexity of a prompt recognition of the syndrome, mostly for HPP in adults. Low ALP and high VitB6 values are mandatory for the genetic screening, this latter remaining the gold standard not only to confirm the clinical diagnosis but also to make differential diagnosis, to identify carriers, to avoid likely dangerous therapy in unrecognized cases.

The Italian registry for patients with Prader-Willi syndrome.

BACKGROUND: Prader-Willi syndrome (PWS) is a rare and complex genetic disease, with numerous implications on metabolic, endocrine, neuropsychomotor systems, and with behavioural and intellectual disorders. Rare disease patient registries are important scientific tools (1) to collect clinical and epidemiologic data, (2) to assess the clinical management including the diagnostic delay, (3) to improve patients' care and (4) to foster research to identify new therapeutic solutions. The European Union has recommended the implementation and use of registries and databases. The main aims of this paper are to describe the process of setting up the Italian PWS register, and to illustrate our preliminary results. MATERIALS AND METHODS: The Italian PWS registry was established in 2019 with the aims (1) to describe the natural history of the disease, (2) to determine clinical effectiveness of health care services, (3) to measure and monitor quality of care of patients. Information from six different variables are included and collected into this registry: demographics, diagnosis and genetics, patient status, therapy, quality of life and mortality. RESULTS: A total of 165 patients (50.3% female vs 49.7% male) were included into Italian PWS registry in 2019-2020 period. Average age at genetic diagnosis was 4.6 years; 45.4% of patients was less than 17 years old aged, while the 54.6% was in adult age (> 18 years old). Sixty-one percent of subjects had interstitial deletion of the proximal long arm of paternal chromosome 15, while 36.4% had uniparental maternal disomy for chromosome 15. Three patients presented an imprinting centre defect and one had a de novo translocation involving chromosome 15. A positive methylation test was demonstrated in the remaining 11 individuals but the underlying genetic defect was not identified. Compulsive food-seeking and hyperphagia was present in 63.6% of patients (prevalently in adults); 54.5% of patients developed morbid obesity. Altered glucose metabolism was present in 33.3% of patients. Central hypothyroidism was reported in 20% of patients; 94.7% of children and adolescents and 13.3% of adult patients is undergoing GH treatment. CONCLUSIONS: The analyses of these six variables allowed to highlight important clinical aspects and natural history of PWS useful to inform future actions to be taken by national health care services and health professionals.