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1.
J Med Genet ; 61(2): 132-141, 2024 Jan 19.
Article in English | MEDLINE | ID: mdl-37580113

ABSTRACT

BACKGROUND: Pathogenic variants in the zinc finger protein coding genes are rare causes of intellectual disability and congenital malformations. Mutations in the ZNF148 gene causing GDACCF syndrome (global developmental delay, absent or hypoplastic corpus callosum, dysmorphic facies; MIM #617260) have been reported in five individuals so far. METHODS: As a result of an international collaboration using GeneMatcher Phenome Central Repository and personal communications, here we describe the clinical and molecular genetic characteristics of 22 previously unreported individuals. RESULTS: The core clinical phenotype is characterised by developmental delay particularly in the domain of speech development, postnatal growth retardation, microcephaly and facial dysmorphism. Corpus callosum abnormalities appear less frequently than suggested by previous observations. The identified mutations concerned nonsense or frameshift variants that were mainly located in the last exon of the ZNF148 gene. Heterozygous deletion including the entire ZNF148 gene was found in only one case. Most mutations occurred de novo, but were inherited from an affected parent in two families. CONCLUSION: The GDACCF syndrome is clinically diverse, and a genotype-first approach, that is, exome sequencing is recommended for establishing a genetic diagnosis rather than a phenotype-first approach. However, the syndrome may be suspected based on some recurrent, recognisable features. Corpus callosum anomalies were not as constant as previously suggested, we therefore recommend to replace the term 'GDACCF syndrome' with 'ZNF148-related neurodevelopmental disorder'.


Subject(s)
Intellectual Disability , Leukoencephalopathies , Humans , Child , Corpus Callosum , Facies , Mutation/genetics , Phenotype , Genotype , Intellectual Disability/genetics , Intellectual Disability/diagnosis , Syndrome , Developmental Disabilities/pathology , DNA-Binding Proteins/genetics , Transcription Factors/genetics
2.
Sex Dev ; 2023 Sep 12.
Article in English | MEDLINE | ID: mdl-37699373

ABSTRACT

BACKGROUND: Our Multidisciplinary Team (MDT) is a large specialized team based in Semarang, Indonesia that cares for a wide variety of pediatric and adult individuals with Differences of Sex Development (DSD) from across Indonesia. Here we describe our work over the last 17 years. METHODS: We analyzed phenotypic, hormonal and genetic findings from clinical records for all patients referred to our MDT during the period 2004 to 2020. RESULTS: Among 1184 DSD patients, 10% had sex chromosome DSD, 67% had 46,XY DSD and 23% had 46,XX DSD. The most common sex chromosome anomaly was Turner syndrome (45,X) (55 cases). For patients with 46,XY DSD under-masculinization was the most common diagnosis (311 cases) and for 46,XX DSD a defect of Müllerian development was most common (131 cases) followed by Congenital Adrenal Hyperplasia (CAH) (116 cases). Sanger sequencing, MLPA and targeted gene sequencing of 257 patients with 46,XY DSD found likely causative variants in 21% (55 cases), with 13 diagnostic genes implicated. The most affected gene coded for the Androgen Receptor. Molecular analysis identified a diagnosis for 69 of 116 patients with CAH, with 62 carrying variants in CYP21A2 including four novel variants, and seven patients carrying variants in CYP11B1. In many cases these genetic diagnoses influenced the clinical management of patients and families. CONCLUSIONS: Our work has highlighted the occurrence of different DSDs in Indonesia. By applying sequencing technologies as part of our clinical care, we have delivered a number of genetic diagnoses and identified novel pathogenic variants in some genes, which may be clinically specific to Indonesia. Genetics can inform many aspects of DSD clinical management, and whilst many of our patients remain undiagnosed, we hope that future testing may provide answers for even more.

3.
medRxiv ; 2023 Jun 16.
Article in English | MEDLINE | ID: mdl-37398376

ABSTRACT

Purpose: De novo variants in CUL3 (Cullin-3 ubiquitin ligase) have been strongly associated with neurodevelopmental disorders (NDDs), but no large case series have been reported so far. Here we aimed to collect sporadic cases carrying rare variants in CUL3, describe the genotype-phenotype correlation, and investigate the underlying pathogenic mechanism. Methods: Genetic data and detailed clinical records were collected via multi-center collaboration. Dysmorphic facial features were analyzed using GestaltMatcher. Variant effects on CUL3 protein stability were assessed using patient-derived T-cells. Results: We assembled a cohort of 35 individuals with heterozygous CUL3 variants presenting a syndromic NDD characterized by intellectual disability with or without autistic features. Of these, 33 have loss-of-function (LoF) and two have missense variants. CUL3 LoF variants in patients may affect protein stability leading to perturbations in protein homeostasis, as evidenced by decreased ubiquitin-protein conjugates in vitro . Specifically, we show that cyclin E1 (CCNE1) and 4E-BP1 (EIF4EBP1), two prominent substrates of CUL3, fail to be targeted for proteasomal degradation in patient-derived cells. Conclusion: Our study further refines the clinical and mutational spectrum of CUL3 -associated NDDs, expands the spectrum of cullin RING E3 ligase-associated neuropsychiatric disorders, and suggests haploinsufficiency via LoF variants is the predominant pathogenic mechanism.

4.
Eur J Pediatr ; 182(8): 3789-3793, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37272991

ABSTRACT

This study is aimed at describing the findings of high-resolution nerve ultrasound in children with Noonan syndrome (NS) and related disorders experiencing pain in their legs. This retrospective cohort study was conducted in the NS expert center of the Radboud University Medical Center in the Netherlands. Patients were eligible if they were younger than 18 years, clinically and genetically diagnosed with NS or a NS related disorder, and experienced pain in their legs. Anamneses and physical examination were performed in all children. In addition, high-resolution nerve ultrasound was used to assess nerve hypertrophy and, if needed, complemented spinal magnetic resonance imaging was performed. Over a period of 6 months, four children, three with NS and one child with NS with multiple lentigines, who experienced pain of their legs were eligible for inclusion. Muscle weakness was found in two of them. High-resolution nerve ultrasound showed (localized) hypertrophic neuropathy in all patients. One child underwent additional spinal magnetic resonance imaging, which showed profound thickening of the nerve roots and plexus.  Conclusion: In the four children included with a NS and related disorders, pain was concomitant with nerve hypertrophy, which suggests an association between these two findings. The use of high-resolution nerve ultrasound and spinal magnetic resonance imaging might result in better understanding of the nature of this pain and the possible association to nerve hypertrophy in patients with NS and related disorders. What is Known: • Children with Noonan syndrome and related disorders may report pain in their legs, which is often interpreted as growing pain. • Some adults with Noonan syndrome and related disorders have hypertrophic neuropathy as a possible cause of neuropathic pain. What is New: • This is the first study using high-resolution nerve ultrasound in children with Noonan syndrome and related disorders experiencing pain in their legs. • Hypertrophic neuropathy was diagnosed as possible cause of pain in four children with Noonan syndrome and related disorders.


Subject(s)
Noonan Syndrome , Adult , Humans , Child , Noonan Syndrome/complications , Noonan Syndrome/diagnosis , Retrospective Studies , Hypertrophy/complications , Pain/etiology , Protein Tyrosine Phosphatase, Non-Receptor Type 11
5.
Hum Genomics ; 17(1): 39, 2023 05 03.
Article in English | MEDLINE | ID: mdl-37138343

ABSTRACT

BACKGROUND: Exome and genome sequencing are the predominant techniques in the diagnosis and research of genetic disorders. Sufficient, uniform and reproducible/consistent sequence coverage is a main determinant for the sensitivity to detect single-nucleotide (SNVs) and copy number variants (CNVs). Here we compared the ability to obtain comprehensive exome coverage for recent exome capture kits and genome sequencing techniques. RESULTS: We compared three different widely used enrichment kits (Agilent SureSelect Human All Exon V5, Agilent SureSelect Human All Exon V7 and Twist Bioscience) as well as short-read and long-read WGS. We show that the Twist exome capture significantly improves complete coverage and coverage uniformity across coding regions compared to other exome capture kits. Twist performance is comparable to that of both short- and long-read whole genome sequencing. Additionally, we show that even at a reduced average coverage of 70× there is only minimal loss in sensitivity for SNV and CNV detection. CONCLUSION: We conclude that exome sequencing with Twist represents a significant improvement and could be performed at lower sequence coverage compared to other exome capture techniques.


Subject(s)
Exome , High-Throughput Nucleotide Sequencing , Humans , Exome/genetics , Exome Sequencing , High-Throughput Nucleotide Sequencing/methods , Genome, Human/genetics , Base Sequence , DNA Copy Number Variations/genetics
7.
Prenat Diagn ; 43(4): 527-543, 2023 04.
Article in English | MEDLINE | ID: mdl-36647814

ABSTRACT

OBJECTIVE: We performed a 1-year evaluation of a novel strategy of simultaneously analyzing single nucleotide variants (SNVs), copy number variants (CNVs) and copy-number-neutral Absence-of-Heterozygosity from Whole Exome Sequencing (WES) data for prenatal diagnosis of fetuses with ultrasound (US) anomalies and a non-causative QF-PCR result. METHODS: After invasive diagnostics, whole exome parent-offspring trio-sequencing with exome-wide CNV analysis was performed in pregnancies with fetal US anomalies and a non-causative QF-PCR result (WES-CNV). On request, additional SNV-analysis, restricted to (the) requested gene panel(s) only (with the option of whole exome SNV-analysis afterward) was performed simultaneously (WES-CNV/SNV) or as rapid SNV-re-analysis, following a normal CNV analysis. RESULTS: In total, 415 prenatal samples were included. Following a non-causative QF-PCR result, WES-CNV analysis was initially requested for 74.3% of the chorionic villus (CV) samples and 45% of the amniotic fluid (AF) samples. In case WES-CNV analysis did not reveal a causative aberration, SNV-re-analysis was requested in 41.7% of the CV samples and 17.5% of the AF samples. All initial analyses could be finished within 2 weeks after sampling. For SNV-re-analysis during pregnancy, turn-around-times (TATs) varied between one and 8 days. CONCLUSION: We show a highly efficient all-in-one WES-based strategy, with short TATs, and the option of rapid SNV-re-analysis after a normal CNV result.


Subject(s)
DNA Copy Number Variations , Fetus , Pregnancy , Female , Humans , Exome Sequencing , Heterozygote , Fetus/diagnostic imaging , Fetus/abnormalities , Nucleotides
8.
Eur J Hum Genet ; 31(1): 81-88, 2023 01.
Article in English | MEDLINE | ID: mdl-36114283

ABSTRACT

Genome sequencing (GS) can identify novel diagnoses for patients who remain undiagnosed after routine diagnostic procedures. We tested whether GS is a better first-tier genetic diagnostic test than current standard of care (SOC) by assessing the technical and clinical validity of GS for patients with neurodevelopmental disorders (NDD). We performed both GS and exome sequencing in 150 consecutive NDD patient-parent trios. The primary outcome was diagnostic yield, calculated from disease-causing variants affecting exonic sequence of known NDD genes. GS (30%, n = 45) and SOC (28.7%, n = 43) had similar diagnostic yield. All 43 conclusive diagnoses obtained with SOC testing were also identified by GS. SOC, however, required integration of multiple test results to obtain these diagnoses. GS yielded two more conclusive diagnoses, and four more possible diagnoses than ES-based SOC (35 vs. 31). Interestingly, these six variants detected only by GS were copy number variants (CNVs). Our data demonstrate the technical and clinical validity of GS to serve as routine first-tier genetic test for patients with NDD. Although the additional diagnostic yield from GS is limited, GS comprehensively identified all variants in a single experiment, suggesting that GS constitutes a more efficient genetic diagnostic workflow.


Subject(s)
Neurodevelopmental Disorders , Humans , Neurodevelopmental Disorders/diagnosis , Neurodevelopmental Disorders/genetics , Genetic Testing/methods , Base Sequence , Chromosome Mapping , Exome Sequencing
9.
J Clin Endocrinol Metab ; 107(11): 3035-3044, 2022 11 23.
Article in English | MEDLINE | ID: mdl-36071555

ABSTRACT

OBJECTIVE: The purpose of this study is to report development of a malignant testicular germ cell tumor (GCT) in 2 young adult males with familial male-limited precocious puberty (FMPP) because of LHCGR pathogenic variants in 2 families. Secondarily, to study the possible relation between FMPP and testicular tumors and to investigate whether FMPP might predispose to development of malignant testicular tumors in adulthood a literature review is conducted. METHODS: Data on 6 cases in 2 families are obtained from the available medical records. In addition, a database search is performed in Cochrane, PubMed, and Embase for studies that report on a possible link between FMPP and testicular tumors. RESULTS: The characteristics of 6 males with FMPP based on activating LH receptor (LHCGR) germline pathogenic variants are described, as are details of the testicular GCTs. Furthermore, a literature review identified 4 more patients with signs of FMPP and a (precursor of) testicular GCT in adolescence or adulthood (age 15-35 years). Additionally, 12 patients with signs of precocious puberty and, simultaneously, occurrence of a Leydig cell adenoma or Leydig cell hyperplasia are reported. CONCLUSION: There is a strong suggestion that FMPP might increase the risk of development of testicular GCTs in early adulthood compared with the risk in the general population. Therefore, prolonged patient monitoring from mid-pubertal age onward including instruction for self-examination and periodic testicular ultrasound investigation in patients with a germline LHCGR pathogenic variant might contribute to early detection and thus early treatment of testicular GCT.


Subject(s)
Puberty, Precocious , Testicular Neoplasms , Adolescent , Adult , Humans , Male , Young Adult , Puberty, Precocious/genetics , Testicular Neoplasms/diagnosis , Testicular Neoplasms/genetics , Testicular Neoplasms/pathology
10.
Am J Med Genet A ; 188(11): 3242-3261, 2022 11.
Article in English | MEDLINE | ID: mdl-35979676

ABSTRACT

Noonan syndrome (NS) has been associated with an increased risk of lymphatic anomalies, with an estimated prevalence of 20%. The prevalence of lymphatic anomalies seems to differ between pathogenic variants. Therefore, this study aims to describe the clinical presentation, prevalence and genotype-phenotype correlations of lymphatic anomalies during life in patients with NS. This retrospective cohort study included patients (n = 115) who were clinically and genetically diagnosed with NS and visited the Noonan expertise Center of the Radboud University Medical Center between January 2015 and March 2021. Data on lymphatic anomalies during lifetime were obtained from medical records. Lymphatic anomalies most often presented as an increased nuchal translucency, chylothorax and/or lymphedema. Prenatal lymphatic anomalies increased the risk of lymphatic anomalies during infancy (OR 4.9, 95% CI 1.7-14.6). The lifetime prevalence of lymphatic anomalies was 37%. Genotype-phenotype correlations showed an especially high prevalence of lymphatic anomalies during infancy and childhood in patients with a pathogenic SOS2 variant (p = 0.03 and p < 0.01, respectively). This study shows that patients with NS have a high predisposition for developing lymphatic anomalies during life. Especially patients with prenatal lymphatic anomalies have an increased risk of lymphatic anomalies during infancy. Genotype-phenotype correlations were found in pathogenic variants in SOS2.


Subject(s)
Noonan Syndrome , Female , Genetic Association Studies , Genotype , Humans , Noonan Syndrome/complications , Noonan Syndrome/epidemiology , Noonan Syndrome/genetics , Pregnancy , Retrospective Studies
11.
Article in English | MEDLINE | ID: mdl-35848593

ABSTRACT

Isolated aldosterone synthase deficiency is a rare autosomal recessive disorder caused by pathogenic variants in CYP11B2, resulting in impaired aldosterone synthesis. We report on a neonate with isolated aldosterone synthase deficiency caused by a novel homozygous CYP11B2 variant Chr8:NM_000498.3:c.400G>A p.(Gly134Arg). The patient presented shortly after birth with severe signs of aldosterone deficiency. Interestingly, segregation analysis revealed that the patient's asymptomatic father was also homozygous for the CYP11B2 variant. Biochemical evaluation of the father indicated subclinical enzyme impairment, characterized by elevated aldosterone precursors. Apparently, this homozygous variant led to different clinical phenotypes in two affected relatives. In this manuscript we elaborate on the performed biochemical and genetic work-up and describe potential pitfalls of CYP11B2 sequencing due to its homology to CYP11B2.

12.
Front Endocrinol (Lausanne) ; 13: 1015973, 2022.
Article in English | MEDLINE | ID: mdl-36589846

ABSTRACT

Background: Congenital Adrenal Hyperplasia (CAH) due to CYP11B1 is a rare autosomal recessive adrenal disorder that causes a decrease in cortisol production and accumulation of adrenal androgens and steroid precursors with mineralocorticoid activity. Clinical manifestations include cortisol deficiency, ambiguous genitalia in females (differences of sex development (DSD)), and hypertension. Medical treatment recommendations are well defined, consisting of glucocorticoid treatment to substitute glucocorticoid deficiency and consequently normalize adrenal androgen and precursors levels. Current guidelines also emphasize the need for specialized multidisciplinary DSD teams and psychosocial support. In many developing countries, care for DSD patients, especially when caused by an adrenal disease, is challenging due to the lack of infrastructure, knowledge, and medication. Objective: The study aims to report the conflicting decision-making process of medical treatment and sex assignment in late-identified CAH patients in developing countries. Methods: We describe the clinical and biochemical findings and the psychological assessment of five affected but untreated family members with CAH due to CYP11B1 deficiency. Results: All patients had a 46,XX karyotype, ambiguous genitalia, low cortisol levels, and hypertension. Two identified as males, two as females, and one had undecided gender. The patients were counselled that refusing treatment will lead to infertility and the potential risk of developing Addisonian crisis and severe hypertension. However, all 46,XX CAH males refused treatment with glucocorticoids due to the expected lowering of adrenal androgens as their main source of testosterone. None of the patients developed Addisonian crisis, probably due to some residual cortisol activity and glucocorticoid activity of elevated adrenal steroid precursors. Conclusion: Medical treatment and sex assignment in late-identified 46,XX CAH patients in Indonesia may often depend on local and cultural factors. The management of DSD conditions may have to be individualized and integrated into the psychological and social context of the affected family.


Subject(s)
Adrenal Hyperplasia, Congenital , Disorders of Sex Development , Hypertension , Female , Humans , Male , Adrenal Hyperplasia, Congenital/drug therapy , Adrenal Hyperplasia, Congenital/genetics , Androgens/therapeutic use , Developing Countries , Disorders of Sex Development/genetics , Disorders of Sex Development/therapy , Glucocorticoids/therapeutic use , Hydrocortisone/therapeutic use , Hypertension/etiology , Hypertension/genetics , Steroid 11-beta-Hydroxylase/genetics , Steroids/therapeutic use
13.
Eur J Hum Genet ; 29(11): 1669-1676, 2021 11.
Article in English | MEDLINE | ID: mdl-34456334

ABSTRACT

Deletions that include the gene TAB2 and TAB2 loss-of-function variants have previously been associated with congenital heart defects and cardiomyopathy. However, other features, including short stature, facial dysmorphisms, connective tissue abnormalities and a variable degree of developmental delay, have only been mentioned occasionally in literature and thus far not linked to TAB2. In a large-scale, social media-based chromosome 6 study, we observed a shared phenotype in patients with a 6q25.1 deletion that includes TAB2. To confirm if this phenotype is caused by haploinsufficiency of TAB2 and to delineate a TAB2-related phenotype, we subsequently sequenced TAB2 in patients with matching phenotypes and recruited patients with pathogenic TAB2 variants detected by exome sequencing. This identified 11 patients with a deletion containing TAB2 (size 1.68-14.31 Mb) and 14 patients from six families with novel truncating TAB2 variants. Twenty (80%) patients had cardiac disease, often mitral valve defects and/or cardiomyopathy, 18 (72%) had short stature and 18 (72%) had hypermobility. Twenty patients (80%) had facial features suggestive for Noonan syndrome. No substantial phenotypic differences were noted between patients with deletions and those with intragenic variants. We then compared our patients to 45 patients from the literature. All literature patients had cardiac diseases, but syndromic features were reported infrequently. Our study shows that the phenotype in 6q25.1 deletions is caused by haploinsufficiency of TAB2 and that TAB2 is associated not just with cardiac disease, but also with a distinct phenotype, with features overlapping with Noonan syndrome. We propose the name "TAB2-related syndrome".


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Cardiomyopathies/genetics , Dwarfism/genetics , Heart Valve Diseases/genetics , Joint Instability/genetics , Phenotype , Cardiomyopathies/pathology , Chromosomes, Human, Pair 6/genetics , Dwarfism/pathology , Gene Deletion , Heart Valve Diseases/pathology , Humans , Joint Instability/pathology , Mitral Valve/pathology , Syndrome
14.
Int J Mol Sci ; 22(12)2021 Jun 15.
Article in English | MEDLINE | ID: mdl-34203967

ABSTRACT

A substantial proportion of subjects with autosomal recessive retinitis pigmentosa (arRP) or Usher syndrome type II (USH2) lacks a genetic diagnosis due to incomplete USH2A screening in the early days of genetic testing. These cases lack eligibility for optimal genetic counseling and future therapy. USH2A defects are the most frequent cause of USH2 and are also causative in individuals with arRP. Therefore, USH2A is an important target for genetic screening. The aim of this study was to assess unscreened or incompletely screened and unexplained USH2 and arRP cases for (likely) pathogenic USH2A variants. Molecular inversion probe (MIP)-based sequencing was performed for the USH2A exons and their flanking regions, as well as published deep-intronic variants. This was done to identify single nucleotide variants (SNVs) and copy number variants (CNVs) in 29 unscreened or partially pre-screened USH2 and 11 partially pre-screened arRP subjects. In 29 out of these 40 cases, two (likely) pathogenic variants were successfully identified. Four of the identified SNVs and one CNV were novel. One previously identified synonymous variant was demonstrated to affect pre-mRNA splicing. In conclusion, genetic diagnoses were obtained for a majority of cases, which confirms that MIP-based sequencing is an effective screening tool for USH2A. Seven unexplained cases were selected for future analysis with whole genome sequencing.


Subject(s)
Cost-Benefit Analysis , Exons/genetics , Extracellular Matrix Proteins/genetics , Molecular Probes/metabolism , RNA Splice Sites/genetics , Retinitis Pigmentosa/genetics , Sequence Analysis, DNA , Usher Syndromes/genetics , Base Sequence , DNA Copy Number Variations/genetics , Gene Deletion , Humans , Polymorphism, Single Nucleotide/genetics , Retinitis Pigmentosa/economics , Usher Syndromes/economics
15.
Am J Hum Genet ; 108(6): 1053-1068, 2021 06 03.
Article in English | MEDLINE | ID: mdl-33909990

ABSTRACT

Truncating variants in exons 33 and 34 of the SNF2-related CREBBP activator protein (SRCAP) gene cause the neurodevelopmental disorder (NDD) Floating-Harbor syndrome (FLHS), characterized by short stature, speech delay, and facial dysmorphism. Here, we present a cohort of 33 individuals with clinical features distinct from FLHS and truncating (mostly de novo) SRCAP variants either proximal (n = 28) or distal (n = 5) to the FLHS locus. Detailed clinical characterization of the proximal SRCAP individuals identified shared characteristics: developmental delay with or without intellectual disability, behavioral and psychiatric problems, non-specific facial features, musculoskeletal issues, and hypotonia. Because FLHS is known to be associated with a unique set of DNA methylation (DNAm) changes in blood, a DNAm signature, we investigated whether there was a distinct signature associated with our affected individuals. A machine-learning model, based on the FLHS DNAm signature, negatively classified all our tested subjects. Comparing proximal variants with typically developing controls, we identified a DNAm signature distinct from the FLHS signature. Based on the DNAm and clinical data, we refer to the condition as "non-FLHS SRCAP-related NDD." All five distal variants classified negatively using the FLHS DNAm model while two classified positively using the proximal model. This suggests divergent pathogenicity of these variants, though clinically the distal group presented with NDD, similar to the proximal SRCAP group. In summary, for SRCAP, there is a clear relationship between variant location, DNAm profile, and clinical phenotype. These results highlight the power of combined epigenetic, molecular, and clinical studies to identify and characterize genotype-epigenotype-phenotype correlations.


Subject(s)
Abnormalities, Multiple/pathology , Adenosine Triphosphatases/genetics , Craniofacial Abnormalities/pathology , DNA Methylation , Epigenesis, Genetic , Growth Disorders/pathology , Heart Septal Defects, Ventricular/pathology , Mutation , Neurodevelopmental Disorders/pathology , Phenotype , Abnormalities, Multiple/genetics , Case-Control Studies , Cohort Studies , Craniofacial Abnormalities/genetics , Female , Genetic Predisposition to Disease , Growth Disorders/genetics , Heart Septal Defects, Ventricular/genetics , Humans , Infant, Newborn , Male , Neurodevelopmental Disorders/genetics
16.
Eur J Hum Genet ; 29(1): 51-60, 2021 01.
Article in English | MEDLINE | ID: mdl-32788663

ABSTRACT

RASopathies are caused by variants in genes encoding components or modulators of the RAS/MAPK signaling pathway. Noonan syndrome is the most common entity among this group of disorders and is characterized by heart defects, short stature, variable developmental delay, and typical facial features. Heterozygous variants in SOS2, encoding a guanine nucleotide exchange factor for RAS, have recently been identified in patients with Noonan syndrome. The number of published cases with SOS2-related Noonan syndrome is still limited and little is known about genotype-phenotype correlations. We collected previously unpublished clinical and genotype data from 17 individuals carrying a disease-causing SOS2 variant. Most individuals had one of the previously reported dominant pathogenic variants; only four had novel changes at the established hotspots for variants that affect protein function. The overall phenotype of the 17 patients fits well into the spectrum of Noonan syndrome and is most similar to the phenotype observed in patients with SOS1-related Noonan syndrome, with ectodermal anomalies as common features and short stature and learning disabilities as relatively infrequent findings compared to the average Noonan syndrome phenotype. The spectrum of heart defects in SOS2-related Noonan syndrome was consistent with the known spectrum of cardiac anomalies in RASopathies, but no specific heart defect was particularly predominating. Notably, lymphatic anomalies were extraordinarily frequent, affecting more than half of the patients. We therefore conclude that SOS2-related Noonan syndrome is associated with a particularly high risk of lymphatic complications that may have a significant impact on morbidity and quality of life.


Subject(s)
Lymphatic System/pathology , Noonan Syndrome/genetics , Phenotype , Son of Sevenless Proteins/genetics , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Mutation , Noonan Syndrome/pathology
17.
J Med Genet ; 57(9): 581-589, 2020 09.
Article in English | MEDLINE | ID: mdl-32303604

ABSTRACT

We present key points from the updated Dutch-Flemish guideline on comprehensive diagnostics in disorders/differences of sex development (DSD) that have not been widely addressed in the current (inter)national literature. These points are of interest to physicians working in DSD (expert) centres and to professionals who come across persons with a DSD but have no (or limited) experience in this area. The Dutch-Flemish guideline is based on internationally accepted principles. Recent initiatives striving for uniform high-quality care across Europe, and beyond, such as the completed COST action 1303 and the European Reference Network for rare endocrine conditions (EndoERN), have generated several excellent papers covering nearly all aspects of DSD. The Dutch-Flemish guideline follows these international consensus papers and covers a number of other topics relevant to daily practice. For instance, although next-generation sequencing (NGS)-based molecular diagnostics are becoming the gold standard for genetic evaluation, it can be difficult to prove variant causality or relate the genotype to the clinical presentation. Network formation and centralisation are essential to promote functional studies that assess the effects of genetic variants and to the correct histological assessment of gonadal material from DSD patients, as well as allowing for maximisation of expertise and possible cost reductions. The Dutch-Flemish guidelines uniquely address three aspects of DSD. First, we propose an algorithm for counselling and diagnostic evaluation when a DSD is suspected prenatally, a clinical situation that is becoming more common. Referral to ultrasound sonographers and obstetricians who are part of a DSD team is increasingly important here. Second, we pay special attention to healthcare professionals not working within a DSD centre as they are often the first to diagnose or suspect a DSD, but are not regularly exposed to DSDs and may have limited experience. Their thoughtful communication to patients, carers and colleagues, and the accessibility of protocols for first-line management and efficient referral are essential. Careful communication in the prenatal to neonatal period and the adolescent to adult transition are equally important and relatively under-reported in the literature. Third, we discuss the timing of (NGS-based) molecular diagnostics in the initial workup of new patients and in people with a diagnosis made solely on clinical grounds or those who had earlier genetic testing that is not compatible with current state-of-the-art diagnostics.


Subject(s)
Disorders of Sex Development/diagnosis , Pathology, Molecular , Rare Diseases/diagnosis , Sexual Development/genetics , Disorders of Sex Development/epidemiology , Disorders of Sex Development/genetics , Disorders of Sex Development/pathology , Europe , Female , Genetic Testing/trends , Guidelines as Topic , High-Throughput Nucleotide Sequencing , Humans , Pregnancy , Rare Diseases/epidemiology , Rare Diseases/genetics , Rare Diseases/pathology
18.
Prenat Diagn ; 40(8): 972-983, 2020 07.
Article in English | MEDLINE | ID: mdl-32333414

ABSTRACT

OBJECTIVE: The purpose of this study was to explore the diagnostic yield and clinical utility of trio-based rapid whole exome sequencing (rWES) in pregnancies of fetuses with a wide range of congenital anomalies detected by ultrasound imaging. METHODS: In this observational study, we analyzed the first 54 cases referred to our laboratory for prenatal rWES to support clinical decision making, after the sonographic detection of fetal congenital anomalies. The most common identified congenital anomalies were skeletal dysplasia (n = 20), multiple major fetal congenital anomalies (n = 17) and intracerebral structural anomalies (n = 7). RESULTS: A conclusive diagnosis was identified in 18 of the 54 cases (33%). Pathogenic variants were detected most often in fetuses with skeletal dysplasia (n = 11) followed by fetuses with multiple major fetal congenital anomalies (n = 4) and intracerebral structural anomalies (n = 3). A survey, completed by the physicians for 37 of 54 cases, indicated that the rWES results impacted clinical decision making in 68% of cases. CONCLUSIONS: These results suggest that rWES improves prenatal diagnosis of fetuses with congenital anomalies, and has an important impact on prenatal and peripartum parental and clinical decision making.


Subject(s)
Congenital Abnormalities/diagnosis , Congenital Abnormalities/genetics , Exome Sequencing , Ultrasonography, Prenatal , Abnormalities, Multiple/diagnosis , Abnormalities, Multiple/genetics , Adult , Decision Making , Female , Fetus/diagnostic imaging , Genetic Testing/methods , Humans , Male , Pregnancy , Prenatal Diagnosis/methods , Reproducibility of Results , Young Adult
19.
Hum Mutat ; 41(5): 1042-1050, 2020 05.
Article in English | MEDLINE | ID: mdl-32097528

ABSTRACT

Pathogenic variants in ZMYND11, which acts as a transcriptional repressor, have been associated with intellectual disability, behavioral abnormalities, and seizures. Only 11 affected individuals have been reported to date, and the phenotype associated with pathogenic variants in this gene have not been fully defined. Here, we present 16 additional patients with predicted pathogenic heterozygous variants in including four individuals from the same family, to further delineate and expand the genotypic and phenotypic spectrum of ZMYND11-related syndromic intellectual disability. The associated phenotype includes developmental delay, particularly affecting speech, mild-moderate intellectual disability, significant behavioral abnormalities, seizures, and hypotonia. There are subtle shared dysmorphic features, including prominent eyelashes and eyebrows, a depressed nasal bridge with bulbous nasal tip, anteverted nares, thin vermilion of the upper lip, and wide mouth. Novel features include brachydactyly and tooth enamel hypoplasia. Most identified variants are likely to result in premature truncation and/or nonsense-mediated decay. Two ZMYND11 variants located in the final exon-p.(Gln586*) (likely escaping nonsense-mediated decay) and p.(Cys574Arg)-are predicted to disrupt the MYND-type zinc-finger motif and likely interfere with binding to its interaction partners. Hence, the homogeneous phenotype likely results from a common mechanism of loss-of-function.


Subject(s)
Cell Cycle Proteins/genetics , Co-Repressor Proteins/genetics , DNA-Binding Proteins/genetics , Genetic Association Studies , Genetic Predisposition to Disease , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Alleles , Child , Child, Preschool , Facies , Female , Genetic Association Studies/methods , Genotype , Haploinsufficiency , Humans , Male , Mutation , Nonsense Mediated mRNA Decay , Phenotype , Syndrome , Zinc Fingers
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