Common clinical findings in patients with 19p13.3 duplication include intrauterine growth restriction, intellectual disability, developmental delay, microcephaly, and distinctive facial features. In this study, we report the case of a patient with 19p13.3 microduplication and novel clinical findings, specifically nephrotic syndrome. A 4-year-old girl was admitted to our hospital in December 2020 with a fever and cough that had persisted for 3 days. A series of treatments, chromosomal microarray analysis (CMA) and whole exome sequencing (WES) were performed. Relevant literature was reviewed using the search terms "19p13.3" and "19p13.3 microduplication syndrome" in the China Knowledge Network, Wanfang Database, Weipu Journal Service Platform, and PubMed (date range: database establishment to September 2023). In addition to common symptoms, such as developmental delay, microcephaly, distinctive facial features, and congenital heart defects, the patient also had nephrotic syndrome, a previously unreported phenomenon. CMA results showed a 3.6 Mb fragment duplication (copy number: 3) in the chr19p13.3 region, containing 127 protein-coding genes (including CELF5, NFIC, SMIM24, PIAS4, ATCAY, MAP2K2, and ZBTB7A). WES revealed a filamin C mutation (p.Glu309Valfs × 11). The mutation status of the patient and her father was heterozygous, whereas the mutation was not detected in the mother. Microduplication in the 19p13.3 region could be one of the genetic factors contributing to the observed clinical phenotypes. However, patients with developmental delay, microcephaly, distinctive facial features, congenital heart defects, and urogenital system disorders may exhibit these manifestations due to various genetic syndromes; therefore, simply considering the possibility of 19p13.3 microduplication syndrome based on these non-specific features is not sufficient. Further comprehensive evaluations, including CMA, should be conducted in conjunction with other genetic tests and detailed clinical examinations to accurately determine the underlying genetic causes.

A small but growing body of scientific literature is emerging about clinical findings in patients with 19p13.3 microdeletion or duplication. Recently, a proximal 19p13.3 microduplication syndrome was described, associated with growth delay, microcephaly, psychomotor delay and dysmorphic features. The aim of our study was to better characterize the syndrome associated with duplications in the proximal 19p13.3 region (prox 19p13.3 dup), and to propose a comprehensive analysis of the underlying genomic mechanism. We report the largest cohort of patients with prox 19p13.3 dup through a collaborative study. We collected 24 new patients with terminal or interstitial 19p13.3 duplication characterized by array-based Comparative Genomic Hybridization (aCGH). We performed mapping, phenotype-genotype correlations analysis, critical region delineation and explored three-dimensional chromatin interactions by analyzing Topologically Associating Domains (TADs). We define a new 377 kb critical region (CR 1) in chr19: 3,116,922-3,494,377, GRCh37, different from the previously described critical region (CR 2). The new 377 kb CR 1 includes a TAD boundary and two enhancers whose common target is PIAS4. We hypothesize that duplications of CR 1 are responsible for tridimensional structural abnormalities by TAD disruption and misregulation of genes essentials for the control of head circumference during development, by breaking down the interactions between enhancers and the corresponding targeted gene.

19p13.3 microduplication syndrome is a newly defined intrauterine onset growth retardation syndrome characterized by microcephaly, moderate intellectual disability, speech delay, and mild dysmorphic features. The PIAS4 gene located in this region plays a crucial role as a transcriptional co-regulator in various cellular pathways including STAT, p53/TP53 and growth hormone (GH) signaling and mutations in this gene are thought to be responsible for clinical features. We present a 10 year-old girl with intrauterine onset growth retardation, microcephaly, and mild facial dysmorphic features. Treatment with GH was started at 4 years and 9 months of age targeting the severe short stature (-3.65 standard deviation score, SDS) since she had significant IGF-1 response to exogenous GH. Microarray study demonstrated a 19p13.3 microduplication of 4.4 Mb. FISH analyses revealed mosaic extra signals (27.5% on blood lymphocytes, and 47% on buccal epithelium) of 19p13.3 region. At the age of 10, her height was at -2.37 SDS, and she had mild intellectual disability which has been described in 19p13.3 microduplication syndrome. We present here a patient with typical findings of 19p13.3 microduplication syndrome and also with a prominent response to GH treatment, which has not been reported previously in this syndrome.

The proximal 19p13.3 microdeletion/microduplication (prox19p13.3del/dup) syndrome is a recently described disorder with common clinical features including developmental delay, intellectual disability, speech delay, facial dysmorphic features with ear defects, anomalies of the hands and feet, umbilical hernia and hypotonia. While deletions are associated with macrocephaly, patients with duplications have microcephaly. The smallest region of overlap in multiple patients (113.5 kb) included three genes and one pseudogene, with a suggested major role of PIAS4 in determination of the phenotype and head size in these patients. Here, we refine the prox19p13.3del/dup with four additional patients: two with microdeletions, one with microduplication and one family with single-nucleotide nonsense variant in PIAS4. The patient with the PIAS4 loss of function variant displayed a phenotype quite similar to deletion patients -including the macrocephaly and many other core features of the syndrome. Patient's SNV was inherited from her mother who is similarly affected. Thus, our data indicate that PIAS4 is a major contributor to the proximal 19p13.3del/dup syndrome phenotype. In summary, we report the first patient with a pathogenic variant in PIAS4- and three additional rearrangements at the proximal 19p13.3 locus. These observations add further evidence about the molecular basis of this microdeletion/microduplication syndrome.

A female patient presented with developmental delay, distinctive facial features, and congenital anomalies, including a heart defect and premature lambdoid synostosis. The patient showed a paternally inherited 16p13.11 microduplication and a de novo 19p13.3 microdeletion involving the mitogen-activated protein kinase kinase 2 gene (MAP2K2), in which mutations cause the cardio-facio-cutaneous (CFC) syndrome. Reports of patients with overlapping 19p13.3 microdeletions of this region describe similar clinical manifestations including distinctive facial features: prominent forehead, horizontal/down-slanting palpebral fissures, long midface, pointed chin/angular jaw, sparse eyebrows, and underdeveloped cheekbones. Some of these findings overlapped to that of the patients with 16p13.11 microduplications and CFC syndrome. Although craniosynostosis was occasionally observed in patients with dominant-negative mutations in RAS/MAP kinase signaling genes (RASopathies) related to CFC syndrome, it was also reported in two patients with 16p13.11 microduplications. Genetic contributions of both chromosomal aberrations were discussed.