Deficiency and overexpression of Rtl1 in the mouse cause distinct muscle abnormalities related to Temple and Kagami-Ogata syndromes.

Temple and Kagami-Ogata syndromes are genomic imprinting diseases caused by maternal and paternal duplication of human chromosome 14, respectively. They exhibit different postnatal muscle-related symptoms as well as prenatal placental problems. Using the mouse models for these syndromes, it has been demonstrated that retrotransposon gag like 1 [Rtl1, also known as paternally expressed 11 (Peg11)] located in the mouse orthologous imprinted region is responsible for the prenatal placental problems because it is an essential placental gene for maintenance of fetal capillary network during gestation. However, the causative imprinted gene for the postnatal muscle-related symptoms remains unknown. Here, we demonstrate that Rtl1 also plays an important role in fetal/neonatal skeletal muscle development: its deletion and overproduction in mice lead to neonatal lethality associated with severe but distinct skeletal muscle defects, similar to those of Temple and Kagami-Ogata syndromes, respectively. Thus, it is strongly suggested that RTL1 is the major gene responsible for the muscle defects in addition to the placental defects in these two genomic imprinting diseases. This is the first example of an LTR retrotransposon-derived gene specific to eutherians contributing to eutherian skeletal muscle development.

Temple syndrome resulting from uniparental disomy is undiagnosed by a methylation assay due to low-level mosaicism for trisomy 14.

We describe a patient with Temple syndrome resulting from maternal uniparental disomy of chromosome 14 who also has low-level mosaicism for trisomy 14. UPD was initially suspected when SNP microarray analysis detected a large region of homozygosity on chromosome 14 and the patient's clinical features were consistent with the phenotype of upd(14)mat. However, SNP arrays cannot prove UPD, as homozygosity may also result from identity by descent. Methylation assays diagnose imprinting disorders such as Prader-Willi, Angelman and Temple syndromes; they detect methylation defects that occur in imprinted loci, which have parent-of-origin-specific expression and have the advantage of making a diagnosis without parental samples. However, in this patient methylation analysis using endpoint PCR detected biparental inheritance. Therefore, sequencing analysis was performed and diagnosed upd(14)mat. Re-examination of the microarray suggested that the explanation for the discrepancy between the array and methylation testing was low-level mosaicism for trisomy 14 and fluorescence in situ hybridization testing detected a trisomic cell line. Thus, this patient's Temple syndrome is a result of a maternal M1 error, which gave a trisomic zygote, followed by loss of the paternal chromosome 14 in an early mitotic division to give maternal UPD with low-level mosaicism for trisomy 14. The methylation assay detected the paternal allele in the trisomic line. The diagnostic failure of the methylation assay in this patient highlights a significant shortcoming of methylation endpoint analysis, especially for Temple syndrome, and underscores the need to use other methods in cases with mosaicism.

Molecular and clinical studies in 8 patients with Temple syndrome.

Temple syndrome (TS14, #616222) is a rare imprinting disorder characterised by phenotypic features including pre- and postnatal growth retardation, muscular hypotonia and feeding difficulties in infancy, early puberty and short stature with small hands and feet and often truncal obesity. It is caused by maternal uniparental disomies, paternal deletions and primary imprinting defects that affect the chromosomal region 14q32 and lead to a disturbed expression of imprinted genes in this region. Here, we present detailed clinical data of 8 patients with Temple syndrome, 4 with an imprinting defect, 2 with an imprinting defect in a mosaic state as well as 1 complete and 1 segmental maternal uniparental disomy of chromosome 14.

Temple syndrome as a differential diagnosis to Prader-Willi syndrome: Identifying three new patients.

The two imprinting syndromes Temple syndrome (TS14) and Prader-Willi syndrome (PWS) share many features in infancy and childhood. TS14 is an important, yet often neglected, differential diagnosis to PWS. We wanted to assess the frequency of TS14 among patients tested for PWS. In all samples submitted to our lab for genetic PWS testing during 2014 and 2015, we consecutively conducted additional analyses for TS14. A total of 143 samples were included. The most frequent indications for testing were developmental delay, overweight, and hypotonia. For TS14 testing, we performed a methylation-sensitive MLPA-kit detecting deletions and methylation aberrations in chromosomal region 14q32. TS14 was confirmed in 3 out of 143 patients (2.1%). In comparison, PWS was also confirmed in three patients. Brief clinical descriptions of the TS14 patients are presented. Temple syndrome is presumably underdiagnosed, and should be considered when testing children for PWS.

NSD1 duplication in Silver-Russell syndrome (SRS): molecular karyotyping in patients with SRS features.

Silver-Russell syndrome (SRS) is a growth retardation syndrome characterized by intrauterine and postnatal growth retardation, relative macrocephaly and protruding forehead, body asymmetry and feeding difficulties. Nearly 50% of cases show a hypomethylation in 11p15.5, in 10% maternal uniparental disomy of chromosome 7 is present. A significant number of patients with SRS features also exhibit chromosomal aberrations. We analyzed 43 individuals referred for SRS genetic testing by molecular karyotyping. Pathogenic variants could be detected in five of them, including a NSD1 duplication in 5q35 and a 14q32 microdeletion. NSD1 deletions are detectable in overgrowth disorders (Sotos syndrome and Beckwith-Wiedemann syndrome), whereas NSD1 duplications are associated with growth retardation. The 14q32 deletion is typically associated with Temple syndrome (TS14), but the identification of a patient in our cohort reflects the clinical overlap between TS14 and SRS. As determination of molecular subtypes is the basis for a directed counseling and therapy, the identification of pathogenic variants in >10% of the total cohort of patients referred for SRS testing and in >16% of characteristic individuals with the characteristic SRS phenotype confirms the need to apply molecular karyotyping in this cohort.

Examinations of maternal uniparental disomy and epimutations for chromosomes 6, 14, 16 and 20 in Silver-Russell syndrome-like phenotypes.

BACKGROUND: Silver-Russell syndrome (SRS) is a growth retardation disorder with a very broad molecular and clinical spectrum. Whereas the association of SRS with imprinting disturbances of chromosomes 11p15.5 and 7 is generally accepted, there are controversial discussions on the involvement of other molecular changes. The recent reports on the occurrence of maternal uniparental disomies of chromosomes 6, 16 and 20 (upd(6, 16, 20)mat), as well as 14q32 imprint alterations in patients with SRS phenotypes raise the question on the involvement of these mutations in the etiology of SRS. METHODS: A cohort of 54 growth retarded patients with SRS features was screened for aberrant methylation patterns of chromsomes 6, 14, 16 and 20. RESULTS: One carrier of a 14q32 epimutation was identified whereas epimutations and maternal UPD for chromosomes 6, 16 and 20 were excluded. CONCLUSIONS: Our data and those from the literature confirm that 14q32 disturbances significantly contribute to the mutation spectrum in this cohort. Furthermore, maternal uniparental disomy of chromosomes 6, 16 and 20 can be observed, but are rare. In case they occur they can be regarded as causative for clinical features.

Temple syndrome as a result of isolated hypomethylation of the 14q32 imprinted DLK1/MEG3 region.

We present a Caucasian female, who was diagnosed at 13 years of age with Temple syndrome (formerly referred to as "maternal UPD 14 phenotype") due to an epigenetic loss of methylation at IG-DMR/MEG3-DMR at the chromosome 14q32 imprinted locus. Clinical features were typical and included intra-uterine growth retardation (IUGR), low birth weight, hypotonia, and poor feeding in the neonatal period; and failure to thrive and developmental delay--particularly in relation to speech--in early childhood. Premature puberty, with short stature and truncal obesity, but normal intelligence, were the key features in teenage years. To date only eight patients with Temple syndrome due to an epigenetic error have been described and the etiology of the methylation defect is currently undetermined. In view of a tendency towards central obesity, patients are at potential risk of early-onset type 2 diabetes mellitus, as well as cardiovascular disease and they, therefore, require appropriate monitoring.

New patients with Temple syndrome caused by 14q32 deletion: Genotype-phenotype correlations and risk of thyroid cancer.

Temple syndrome (TS) is caused by abnormal expression of genes at the imprinted locus 14q32. A subset of TS patients carry 14q32 deletions of paternal origin. We aimed to define possible genotype-phenotype correlations and to highlight the prevalence of thyroid dysfunction, which is a previously unreported feature of TS. We described four new patients who carry deletions of paternal origin at 14q32 detected by array-CGH and reviewed nine patients reported in the medical literature. We compared clinical features with respect to deletion size and position. Expression of DLK1 is altered in all the patients with TS, but intellectual disability (ID) is present only in patients with larger deletions extending proximally to the imprinted locus. This study led to the identification of an ID "critical region" containing four annotated genes including YY1 as the strongest candidate. Furthermore, we described three patients with thyroid dysfunction, which progressed to papillary carcinoma at a very young age in two of them. We conclude that DLK1 loss of function is likely to be responsible for the core features of TS, while haploinsufficiency of a gene outside the imprinted region causes ID. Thyroid cancer may be an unrecognized feature and monitoring for thyroid dysfunction should thus be considered in TS patients.

Temple syndrome: improving the recognition of an underdiagnosed chromosome 14 imprinting disorder: an analysis of 51 published cases.

Chromosome 14 harbours an imprinted locus at 14q32. Maternal uniparental disomy of chromosome 14, paternal deletions and loss of methylation at the intergenic differentially methylated region (IG-DMR) result in a human phenotype of low birth weight, hypotonia, early puberty and markedly short adult stature. The analysis of the world literature of 51 cases identifies the key features that will enhance diagnosis and potentially improve treatment. We found a median birth weight SD score (SDS) of -1.88 and median adult final height of -2.04 SDS. Hypotonia and motor delay were reported in 93% and 83% of cases, respectively. Early puberty was reported in 86% of cases with the mean age of menarche at 10 years and 2 months of age. Small hands and feet were reported frequently (87% and 96%, respectively). Premature birth was common (30%) and feeding difficulties frequently reported (n = 22). There was evidence of mildly reduced intellectual ability (measured IQ 75-95). Obesity was reported in 49% of cases, and three patients developed type 2 diabetes mellitus. Two patients were reported to have recurrent hypoglycaemia, and one of these patients was subsequently demonstrated to be growth hormone deficient and started replacement therapy. We propose the use of the name 'Temple syndrome' for this condition and suggest that improved diagnosis and long-term monitoring, especially of growth and cardiovascular risk factors, is required.

Novel 14q32.2 paternal deletion encompassing the whole DLK1 gene associated with Temple syndrome.

BACKGROUND: Temple syndrome (TS14) is a rare imprinting disorder caused by maternal UPD14, imprinting defects or paternal microdeletions which lead to an increase in the maternal expressed genes and a silencing the paternally expressed genes in the 14q32 imprinted domain. Classical TS14 phenotypic features include pre- and postnatal short stature, small hands and feet, muscular hypotonia, motor delay, feeding difficulties, weight gain, premature puberty along and precocious puberty. METHODS: An exon array comparative genomic hybridization was performed on a patient affected by psychomotor and language delay, muscular hypotonia, relative macrocephaly, and small hand and feet at two years old. At 6 years of age, the proband presented with precocious thelarche. Genes dosage and methylation within the 14q32 region were analyzed by MS-MLPA. Bisulfite PCR and pyrosequencing were employed to quantification methylation at the four known imprinted differentially methylated regions (DMR) within the 14q32 domain: DLK1 DMR, IG-DMR, MEG3 DMR and MEG8 DMR. RESULTS: The patient had inherited a 69 Kb deletion, encompassing the entire DLK1 gene, on the paternal allele. Relative hypermethylation of the two maternally methylated intervals, DLK1 and MEG8 DMRs, was observed along with normal methylation level at IG-DMR and MEG3 DMR, resulting in a phenotype consistent with TS14. Additional family members with the deletion showed modest methylation changes at both the DLK1 and MEG8 DMRs consistent with parental transmission. CONCLUSION: We describe a girl with clinical presentation suggestive of Temple syndrome resulting from a small paternal 14q32 deletion that led to DLK1 whole-gene deletion, as well as hypermethylation of the maternally methylated DLK1-DMR.

A long way to syndromic short stature.

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.

The genetic etiology is a relevant cause of central precocious puberty.

OBJECTIVES: The etiology of central precocious puberty (CPP) has expanded with identification of new genetic causes, including the monogenic deficiency of Makorin-Ring-Finger-Protein-3 (MKRN3). We aimed to assess the prevalence of CPP causes and the predictors of genetic involvement in this phenotype. DESIGN: A retrospective cohort study for an etiological survey of patients with CPP from a single academic center. METHODS: All patients with CPP had detailed medical history, phenotyping, and brain magnetic resonance imaging (MRI); those with negative brain MRI (apparently idiopathic) were submitted to genetic studies, mainly DNA sequencing studies, genomic microarray, and methylation analysis. RESULTS: We assessed 270 patients with CPP: 50 (18.5%) had CPP-related brain lesions (34 [68%] congenital lesions), whereas 220 had negative brain MRI. Of the latter, 174 (165 girls) were included for genetic studies. Genetic etiologies were identified in 22 patients (20 girls), indicating an overall frequency of genetic CPP of 12.6% (22.2% in boys and 12.1% in girls). The most common genetic defects were MKRN3, Delta-Like-Non-Canonical-Notch-Ligand-1 (DLK1), and Methyl-CpG-Binding-Protein-2 (MECP2) loss-of-function mutations, followed by 14q32.2 defects (Temple syndrome). Univariate logistic regression identified family history (odds ratio [OR] 3.3; 95% CI 1.3-8.3; P = .01) and neurodevelopmental disorders (OR 4.1; 95% CI 1.3-13.5; P = .02) as potential clinical predictors of genetic CPP. CONCLUSIONS: Distinct genetic causes were identified in 12.6% patients with apparently idiopathic CPP, revealing the genetic etiology as a relevant cause of CPP in both sexes. Family history and neurodevelopmental disorders were suggested as predictors of genetic CPP. We originally proposed an algorithm to investigate the etiology of CPP including genetic studies.

Comprehensive study on central precocious puberty: molecular and clinical analyses in 90 patients.

CONTEXT: Defects in MKRN3, DLK1, KISS1, and KISS1R and some disorders, such as Temple syndrome (TS14), cause central precocious puberty (CPP). Recently, pathogenic variants (PVs) in MECP2 have been reported to be associated with CPP. OBJECTIVE: We aimed to clarify the contribution of (epi)genetic abnormalities to CPP and clinical and hormonal features in each etiology. SUBJECTS AND METHODS: We conducted targeted sequencing for MKRN3, DLK1, MECP2, KISS1, and KISS1R and methylation analysis for screening of imprinting disorders such as TS14 associated with CPP in 90 patients with CPP (no history of brain injuries and negative brain MRI) and collected their clinical and laboratory data. We measured serum DLK1 levels in three patients with TS14 and serum MKRN3 levels in two patients with MKRN3 genetic defects, together with some etiology-unknown patients with CPP and controls. RESULTS: We detected eight patients with TS14 (six, epimutation; one, mosaic maternal uniparental disomy chromosome 14; one, microdeletion) and three patients with MKRN3 genetic defects (one, PV; one, 13-bp deletion in the 5'-untranslated region (5'-UTR); one, microdeletion) with family histories of paternal early puberty. There were no patients with PVs identified in MECP2, KISS1, or KISS1R. We confirmed low serum MKRN3 level in the patient with a deletion in 5'-UTR. The median height at initial evaluation of TS14 patients was lower than that of all patients. Six patients with TS14 were born small for gestational age (SGA). CONCLUSION: (Epi)genetic causes were identified in 12.2% of patients with CPP at our center. For patients with CPP born SGA or together with family histories of paternal early puberty, (epi)genetic testing for TS14 and MKRN3 genetic defects should be considered. (271/250).

A Male Japanese Patient with Temple Syndrome Complicated by Type 2 Diabetes Mellitus.

We herein present the case of a 21-year-old male Japanese diabetic patient with Temple syndrome, caused by maternal uniparental disomy of chromosome 14. The patient was overweight and had type 2 diabetes, dyslipidemia, metabolic dysfunction-associated steatotic liver disease, and microalbuminuria. He had an increased fat mass in the truncal region and a decreased lean mass throughout the body. This may lead to insulin resistance due to the absence of delta-like homolog 1 (DLK1) and retrotransposon gag-like 1 (RTL1). The patient had experienced social withdrawal at home (hikikomori in Japanese), had poorly controlled type 2 diabetes, and was overweight despite receiving diet therapy and oral hypoglycemic agents.

A Long-term Follow-up of a Late Diagnosed Patient with Temple Syndrome - a Case Report.

Temple syndrome (TS) is a rare imprinting disorder, caused by alterations in the critical imprinted region 14q32 of chromosome 14. It is characterized by pre- and postnatal growth retardation, truncal hypotonia and facial dysmorphism in the neonatal period. We report a 18-year-old girl with a late diagnosis presenting all typical signs and symptoms of Temple syndrome - small for gestational age at birth, feeding difficulties, muscle hypotonia and delayed developmental milestones, central precocious puberty, truncal obesity and reduced growth. The patient is the second reported in the literature with signs of clinical and biochemical hyperandrogenism and the first treated with Dehydrocortisone®, with a good response. The clinical diagnosis of this patient was achieved after a long-term follow up at a single center of rare endocrine diseases, and a molecular genetics diagnosis of complete hypomethylation of 14q32 chromosome imprinting center (DLK/GTL2) was recently established. Growth hormone (GH) treatment was not given and although precocious puberty was treated in line with standard protocols, patient's final height remained below the target range. Increased awareness of Temple syndrome and timely molecular diagnosis enables improvement of clinical care of these patients as well as prevention of inherent metabolic consequences.

The Effects of 5 Years of Growth Hormone Treatment on Growth and Body Composition in Patients with Temple Syndrome.

INTRODUCTION: Temple syndrome (TS14) is a rare imprinting disorder caused by maternal uniparental disomy of chromosome 14, paternal deletion of 14q32.2, or an isolated methylation defect. Most patients with TS14 develop precocious puberty. Some patients with TS14 are treated with growth hormone (GH). However, evidence for the effectiveness of GH treatment in patients with TS14 is limited. METHODS: This study describes the effect of GH treatment in 13 children and provides a subgroup analysis of 5 prepubertal children with TS14. We studied height, weight, body composition by dual-energy X-ray absorptiometry, resting energy expenditure (REE), and laboratory parameters during 5 years of GH treatment. RESULTS: In the entire group, mean (95% CI) height SDS increased significantly during 5 years of GH treatment from -1.78 (-2.52; -1.04) to 0.11 (-0.66; 0.87). Fat mass percentage SDS decreased significantly during the first year of GH, and lean body mass (LBM) SDS and LBM index increased significantly during 5 years of treatment. IGF-1 and IGF-BP3 levels rose rapidly during GH treatment, and the IGF-1/IGF-BP3 molar ratio remained relatively low. Thyroid hormone levels, fasting serum glucose, and insulin levels remained normal. In the prepubertal group, median (interquartile range [IQR]) height SDS, LBM SDS, and LBM index also increased. REE was normal at start and did not change during 1 year of treatment. Five patients reached adult height and their median (IQR) height SDS was 0.67 (-1.83; -0.01). CONCLUSION: GH treatment in patients with TS14 normalizes height SDS and improves body composition. There were no adverse effects or safety concerns during GH treatment.

The Spectrum of the Prader-Willi-like Pheno- and Genotype: A Review of the Literature.

Prader-Willi syndrome (PWS) is a rare genetic syndrome, caused by the loss of expression of the paternal chromosome 15q11-q13 region. Over the past years, many cases of patients with characteristics similar to PWS, but without a typical genetic aberration of the 15q11-q13 region, have been described. These patients are often labelled as Prader-Willi-like (PWL). PWL is an as-yet poorly defined syndrome, potentially affecting a significant number of children and adults. In the current clinical practice, patients labelled as PWL are mostly left without treatment options. Considering the similarities with PWS, children with PWL might benefit from the same care and treatment as children with PWS. This review gives more insight into the pheno- and genotype of PWL and includes 86 papers, containing 368 cases of patients with a PWL phenotype. We describe mutations and aberrations for consideration when suspicion of PWS remains after negative testing. The most common genetic diagnoses were Temple syndrome (formerly known as maternal uniparental disomy 14), Schaaf-Yang syndrome (truncating mutation in the MAGEL2 gene), 1p36 deletion, 2p deletion, 6q deletion, 6q duplication, 15q deletion, 15q duplication, 19p deletion, fragile X syndrome, and Xq duplication. We found that the most prevalent symptoms in the entire group were developmental delay/intellectual disability (76%), speech problems (64%), overweight/obesity (57%), hypotonia (56%), and psychobehavioral problems (53%). In addition, we propose a diagnostic approach to patients with a PWL phenotype for (pediatric) endocrinologists. PWL comprises a complex and diverse group of patients, which calls for multidisciplinary care with an individualized approach.

Maintenance of methylation profile in imprinting control regions in human induced pluripotent stem cells.

BACKGROUND: Parental imprinting is an epigenetic mechanism that leads to monoallelic expression of a subset of genes depending on their parental origin. Imprinting disorders (IDs), caused by disturbances of imprinted genes, are a set of rare congenital diseases that mainly affect growth, metabolism and development. To date, there is no accurate model to study the physiopathology of IDs or test therapeutic strategies. Human induced pluripotent stem cells (iPSCs) are a promising cellular approach to model human diseases and complex genetic disorders. However, aberrant hypermethylation of imprinting control regions (ICRs) may appear during the reprogramming process and subsequent culture of iPSCs. Therefore, we tested various conditions of reprogramming and culture of iPSCs and performed an extensive analysis of methylation marks at the ICRs to develop a cellular model that can be used to study IDs. RESULTS: We assessed the methylation levels at seven imprinted loci in iPSCs before differentiation, at various passages of cell culture, and during chondrogenic differentiation. Abnormal methylation levels were found, with hypermethylation at 11p15 H19/IGF2:IG-DMR and 14q32 MEG3/DLK1:IG-DMR, independently of the reprogramming method and cells of origin. Hypermethylation at these two loci led to the loss of parental imprinting (LOI), with biallelic expression of the imprinted genes IGF2 and DLK1, respectively. The epiPS™ culture medium combined with culturing of the cells under hypoxic conditions prevented hypermethylation at H19/IGF2:IG-DMR (ICR1) and MEG3/DLK1:IG-DMR, as well as at other imprinted loci, while preserving the proliferation and pluripotency qualities of these iPSCs. CONCLUSIONS: An extensive and quantitative analysis of methylation levels of ICRs in iPSCs showed hypermethylation of certain ICRs in human iPSCs, especially paternally methylated ICRs, and subsequent LOI of certain imprinted genes. The epiPS™ culture medium and culturing of the cells under hypoxic conditions prevented hypermethylation of ICRs in iPSCs. We demonstrated that the reprogramming and culture in epiPS™ medium allow the generation of control iPSCs lines with a balanced methylation and ID patient iPSCs lines with unbalanced methylation. Human iPSCs are therefore a promising cellular model to study the physiopathology of IDs and test therapies in tissues of interest.

Temple Syndrome: Clinical Findings, Body Composition and Cognition in 15 Patients.

BACKGROUND: Temple syndrome (TS14) is an imprinting disorder caused by a maternal uniparental disomy of chromosome 14 (UPD(14)mat), paternal deletion of 14q32 or an isolated methylation defect of the MEG3-DMR. Studies on phenotypical characteristics in TS14 are scarce and patients with TS14 often experience delay in diagnosis, which has adverse effects on their health. TS14 is often characterized as either Prader-Willi-like, Silver-Russell-like or as a Silver-Russell spectrum disorder. METHODS: This study describes 15 patients with TS14 who visited the Dutch Reference Center for Prader-Willi-like from December 2018 to January 2022. RESULTS: Eight patients had UPD(14)mat and seven a methylation defect. The most common symptoms were intra-uterine growth retardation (IUGR) (100%), hypotonia (100%), precocious puberty (89%), small for gestational age (SGA) birth (67%), tube feeding after birth (53%) and psycho-behavioral problems (53%). Median (interquartile range (IQR)) IQ was 91.5 (84.25; 100.0), whilst many patients were enrolled in special education (54%). The median (IQR) fat mass % (FM%) SDS was 2.53 (2.26; 2.90) and lean body mass (LBM) SDS -2.03 (-3.22; -1.28). There were no significant differences in clinical characteristics between patients with a UPD(14)mat and a methylation defect. CONCLUSIONS: Our patients share a distinct phenotype consisting of IUGR, SGA birth, precocious puberty, hypotonia, tube feeding after birth, psycho-behavioral problems and abnormal body composition with a high FM% and low LBM. Whilst similarities with Prader-Willi syndrome (PWS) and Silver-Russell syndrome (SRS) exist, TS14 is a discernible syndrome, deserving a tailored clinical approach. Testing for TS14 should be considered in patients with a PWS or SRS phenotype in infancy if PWS/SRS testing is negative.

Case report: Prenatal diagnosis of Kagami-Ogata syndrome in a Chinese family.

The aim of this work was to explore the genetic cause of the proband (Ⅲ2) presenting with polyhydramnios and gastroschisis. Copy number variation sequencing (CNV-seq), methylation-specific multiplex PCR (MS-PCR), and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) were used to characterize the genetic etiology. CNV-seq revealed a deletion of 732.26 kb at 14q32.2q32.31 in the proband (Ⅲ2) and its mother (Ⅱ2). MS-PCR showed the maternal allele was missing in the proband, while paternal allele was missing in its mother. MS-MLPA showed deletion of the DLK1, MEG3, MIR380, and RTL1 genes of both the proband and its mother. MEG3 imprinting gene methylation increased in the proband, while decreased in its mother. It was indicated that a maternally transmitted deletion was responsible for Kagami-Ogata syndrome in the proband (Ⅲ2), and the de novo paternal deletion resulted in Temple syndrome in the mother (Ⅱ2). Prenatal diagnosis was provided at 17+3 weeks of pregnancy on the mother's fourth pregnancy (Ⅲ4). Fortunately, the karyotype and single-nucleotide polymorphism array (SNP array) results were normal. The current investigation provided the detection methods for imprinted gene diseases, expanded the phenotype spectrum of the disease, and obtained the insight into the diagnosis, prenatal diagnosis, and genetic counseling of the disease.