Background/Objectives: Schuurs–Hoeijmakers syndrome (SHMS), also known as PACS1 neurodevelopmental disorder, is a rare condition characterized by intellectual disability, distinctive craniofacial abnormalities, and congenital malformations. SHMS has already been associated with variants in the PACS1 gene in 63 patients. In this study, we describe 10 new Italian SHMS patients all harboring the common de novo p.(Arg203Trp) variant. Methods: The 10 patients we studied were evaluated by clinical geneticists and child neurologists and a detailed description of clinical features was recorded. Data were then coded using the Human Phenotype Ontology (HPO) terms. The recurrent p.(Arg203Trp) variant in PACS1 was identified by clinical exome sequencing or whole exome sequencing in trio using standard methodologies. To facilitate mutation identification, we designed a new PCR-RFLP strategy adopting the endonuclease DpnII. Results: We define a detailed clinical phenotyping in patients with intellectual disability and facial characteristics (thick eyebrows, down-slanting palpebral fissures, ocular hypertelorism, low-set ears, a thin upper lip, and a wide mouth) that can help clinicians form a more efficient diagnosis of SHMS even through neuroimaging and neuropsychological evaluation. Conclusions: Our series of 10 newly affected Italian children highlights specific clinical features that may help clinicians recognize and better manage this syndrome, contributing to precision medicine approaches in medical genetics.

Background: Silver-Russell Syndrome (SRS, MIM #180860) is a clinically and genetically heterogeneous disorder characterized by intrauterine and postnatal growth retardation; SRS is also accompanied by dysmorphic features such as triangular facial appearance, broad forehead, body asymmetry and significant feeding difficulties. The incidence is unknown but estimated at 1:30,000-100,000 live births. The diagnosis of SRS is guided by specific criteria described in the Netchine–Harbison clinical scoring system (NH-CSS). Case presentation: Hereby we describe four patients with syndromic short stature in whom, despite fitting the criteria for SRS genetic analysis (and one on them even meeting the clinical criteria for SRS), molecular analysis actually diagnosed a different syndrome. Some additional features such as hypotonia, microcephaly, developmental delay and/or intellectual disability, and family history of growth failure, were actually discordant with SRS in our cohort. Conclusions: The clinical resemblance of other short stature syndromes with SRS poses a risk of diagnostic failure, in particular when clinical SRS only criteria are met, allowing SRS diagnosis in the absence of a positive result of a genetic test. The presence of additional features atypical for SRS diagnosis becomes a red flag for a more extensive and thorough analysis. The signs relevant to the differential diagnosis should be valued as much as possible since a correct diagnosis of these patients is the only way to provide the appropriate care pathway, a thorough genetic counselling, prognosis definition, follow up setting, appropriate monitoring and care of possible medical problems.

SATB1 (MIM #602075) is a relatively new gene reported only in recent years in association with neurodevelopmental disorders characterized by variable facial dysmorphisms, global developmental delay, poor or absent speech, altered electroencephalogram (EEG), and brain abnormalities on imaging. To date about thirty variants in forty-four patients/children have been described, with a heterogeneous spectrum of clinical manifestations. In the present study, we describe a new patient affected by mild intellectual disability, speech disorder, and non-specific abnormalities on EEG and neuroimaging. Family studies identified a new de novo frameshift variant c.1818delG (p.(Gln606Hisfs*101)) in SATB1. To better define genotype–phenotype associations in the different types of reported SATB1 variants, we reviewed clinical data from our patient and from the literature and compared manifestations (epileptic activity, EEG abnormalities and abnormal brain imaging) due to missense variants versus those attributable to loss-of-function/premature termination variants. Our analyses showed that the latter variants are associated with less severe, non-specific clinical features when compared with the more severe phenotypes due to missense variants. These findings provide new insights into SATB1-related disorders.

Background: Some chromatinopathies may present with common clinical findings (intellectual disability, brain and limb malformation, facial dysmorphism). Furthermore, one of their cardinal shared features is growth dysregulation.We aimed to assess and deepen this resemblance in three specific conditions, namely Wiedemann-Steiner (WDSTS), Kleefstra (KLEFS1) and Coffin-Siris syndrome (CSS1), with a particular focus on possible metabolic roots. Methods: Eleven patients were enrolled, three with WDSTS, five with KLEFS1 and three with CSS1, referring to Fondazione IRCCS Ca’ Granda Ospedale Maggiore, Milan, Italy. We performed both a physical examination with detailed anthropometric measurements and an evaluation of the patients’ REE (rest energy expenditure) by indirect calorimetry, comparing the results with age- and sex-matched healthy controls. Results: We observed new clinical features and overlap between these conditions suggesting that different disturbances of epigenetic machinery genes can converge on a common effect, leading to overlapping clinical phenotypes. The REE was not distinguishable between the three conditions and healthy controls. Conclusions: Epigenetic machinery plays an essential role both in growth regulation and in neurodevelopment; we recommend evaluating skeletal [craniovertebral junction abnormalities (CVJ) polydactyly], otolaryngological [obstructive sleep apnea syndrome (OSAs), recurrent otitis media], dental [tooth agenesis, talon cusps], and central nervous system (CNS) [olfactory bulbs and cerebellum anomalies] features. These features could be included in monitoring guidelines. Further studies are needed to deepen the knowledge about energy metabolism.