The Richieri-Costa and Pereira syndrome: report of two Brazilian siblings and review of literature

Richieri-Costa and Pereira syndrome is a rare autosomal recessive disorder characterized specially by Pierre Robin sequence with cleft mandible and limb anomalies. There are a typical laryngeal anomaly which encompass short and round larynx, absent or abnormal epiglottis, and abnormal aryepiglottic folds. Most patients reported were from Brazil. We describe a brother and sister with Richieri-Costa and Pereira syndrome on another Brazilian family documenting their physical findings and laryngeal defects. We also review the literature and discuss the main clinical characteristics and etiology.     

Expanding the genotypic and phenotypic spectrum of severe serine biosynthesis disorders

Serine biosynthesis disorders comprise a spectrum of very rare autosomal recessive inborn errors of metabolism with wide phenotypic variability. Neu–Laxova syndrome represents the most severe expression and is characterized by multiple congenital anomalies and pre‐ or perinatal lethality. Here, we present the mutation spectrum and a detailed phenotypic analysis in 15 unrelated families with severe types of serine biosynthesis disorders. We identified likely disease‐causing variants in the PHGDH and PSAT1 genes, several of which have not been reported previously. Phenotype analysis and a comprehensive review of the literature corroborates the evidence that serine biosynthesis disorders represent a continuum with varying degrees of phenotypic expression and suggest that even gradual differences at the severe end of the spectrum may be correlated with particular genotypes. We postulate that the individual residual enzyme activity of mutant proteins is the major determinant of the phenotypic variability, but further functional studies are needed to explore effects at the enzyme protein level.     

Expanding the phenotypic and genotypic spectrum of Wiedemann–Steiner syndrome: First patient from India

Wiedemann–Steiner syndrome (WWS) is a rare disorder characterized by hypotonia, postnatal growth restriction, striking facial dysmorphism, and hirsutism. It is caused by heterozygous pathogenic variants in KMT2A. This gene has an established role in histone methylation, which explains the overlap of WWS with syndromes caused by genes involved in chromatin remodeling. We describe an infant with a novel single base pair deletion in KMT2A with features consistent with WWS, as well as additional features of stenosis of aqueduct of Sylvius and broad toes. The usefulness of Face2Gene as a tool for identification of dysmorphology syndromes is discussed, as in this patient, it suggested WWS as the top candidate disorder. To the best of our knowledge, this is the first patient of WWS reported from India, with a novel genotype and expanded phenotype.     

Branchio-oto-renal syndrome: the mutation spectrum in EYA1 and its phenotypic consequences

EYA1 mutations cause branchio-oto-renal (BOR) syndrome. These mutations include single nucleotide transitions and transversions, small duplications and deletions, and complex genomic rearrangements. The last cannot be detected by coding sequence analysis of EYA1. We sought to refine the clinical diagnosis of BOR syndrome by analyzing phenotypic data from families segregating EYA1 disease-causing mutations. Based on genotype-phenotype analyses, we propose new criteria for the clinical diagnosis of BOR syndrome. We found that in approximately 40% of persons meeting our criteria, EYA1 mutations were identified. Of these mutations, 80% were coding sequence variants identified by SSCP, and 20% were complex genomic rearrangements identified by a semiquantitative PCR-based screen. We conclude that genetic testing of EYA1 should include analysis of the coding sequence and a screen for complex rearrangements.     

Comprehensive genotype‐phenotype correlation in AP‐4 deficiency syndrome; Adding data from a large cohort of Iranian patients

Mutations in adaptor protein complex‐4 (AP‐4) genes have first been identified in 2009, causing a phenotype termed as AP‐4 deficiency syndrome. Since then several patients with overlapping phenotypes, comprised of intellectual disability (ID) and spastic tetraplegia have been reported. To delineate the genotype‐phenotype correlation of the AP‐4 deficiency syndrome, we add the data from 30 affected individuals from 12 out of 640 Iranian families with ID in whom we detected disease‐causing variants in AP‐4 complex subunits, using next‐generation sequencing. Furthermore, by comparing genotype‐phenotype findings of those affected individuals with previously reported patients, we further refine the genotype‐phenotype correlation in this syndrome. The most frequent reported clinical findings in the 101 cases consist of ID and/or global developmental delay (97%), speech disorders (92.1%), inability to walk (90.1%), spasticity (77.2%), and microcephaly (75.2%). Spastic tetraplegia has been reported in 72.3% of the investigated patients. The major brain imaging findings are abnormal corpus callosum morphology (63.4%) followed by ventriculomegaly (44.5%). Our result might suggest the AP‐4 deficiency syndrome as a major differential diagnostic for unknown hereditary neurodegenerative disorders.     

Oral‐facial‐digital syndrome type 1 in males: Congenital heart defects are included in its phenotypic spectrum

Oral‐facial‐digital syndrome type 1 (OFD1; OMIM# 311200) is an X‐linked dominant ciliopathy caused by mutations in the OFD1 gene. This condition is characterized by facial anomalies and abnormalities of oral tissues, digits, brain, and kidneys. Almost all affected patients are female, as OFD1 is presumed to be lethal in males, mostly in the first or second trimester of pregnancy. Live born males with OFD1 are a rare occurrence, with only five reported patients to date. In four patients the presence of a congenital heart defect (CHD) was observed. Here, we report an affected male fetus with a hemizygous de novo mutation in OFD1 (c.2101C>T; p.(Gln701*)). Ultrasound examination demonstrated severe hydrocephalus, a hypoplastic cerebellum and a hypoplastic left ventricle of the heart. The pregnancy was terminated at 16 weeks of gestation because of poor prognosis. Post‐mortem examination of the fetus confirmed severe hypoplasia of the left ventricle of the heart. We emphasize that CHDs should be included in the phenotypic spectrum of OFD1 in males. This justifies molecular analysis of OFD1 when CHD is encountered prenatally in combination with one or more phenotypic features previously described in the OFD1 gene alteration spectrum. The underlying pathogenesis of CHD in OFD1 (and other ciliopathies) probably involves dysfunction of the primary cilia regarding coordination of left‐right signalling during early heart development. Whether these CHDs wholly or partly result from defective left right signalling, in which different types of cilia are known to play a critical role, remains a topic of research.     

Expansion of the genotypic and phenotypic spectrum of CTCF-related disorder guides clinical management: 43 new subjects and a comprehensive literature review

Monoallelic variants of CTCF cause an autosomal dominant neurodevelopmental disorder with a wide range of features, including impacts on the brain, growth, and craniofacial development. A growing number of subjects with CTCF-related disorder (CRD) have been identified due to the increased application of exome sequencing, and further delineation of the clinical spectrum of CRD is needed. Here, we examined the clinical features, including facial profiles, and genotypic spectrum of 107 subjects with identified CTCF variants, including 43 new and 64 previously described subjects. Among the 43 new subjects, 23 novel variants were reported. The cardinal clinical features in subjects with CRD included intellectual disability/developmental delay (91%) with speech delay (65%), motor delay (53%), feeding difficulties/failure to thrive (66%), ocular abnormalities (56%), musculoskeletal anomalies (53%), and behavioral problems (52%). Other congenital anomalies were also reported, but none of them were common. Our findings expanded the genotypic and phenotypic spectrum of CRD that will guide genetic counseling, management, and surveillance care for patients with CRD. Additionally, a newly built facial gestalt on the Face2Gene tool will facilitate prompt recognition of CRD by physicians and shorten a patient's diagnostic odyssey.     

QRICH1 variants in Ververi‐Brady syndrome—delineation of the genotypic and phenotypic spectrum

Ververi‐Brady syndrome (VBS, # 617982) is a rare developmental disorder, and loss‐of‐function variants in QRICH1 were implicated in its etiology. Furthermore, a recognizable phenotype was proposed comprising delayed speech, learning difficulties and dysmorphic signs. Here, we present four unrelated individuals with one known nonsense variant (c.1954C > T; p.[Arg652*]) and three novel de novo QRICH1 variants, respectively. These included two frameshift mutations (c.832_833del; p.(Ser278Leufs*25), c.1812_1813delTG; p.(Glu605Glyfs*25)) and interestingly one missense mutation (c.2207G > A; p.[Ser736Asn]), expanding the mutational spectrum. Enlargement of the cohort by these four individuals contributes to the delineation of the VBS phenotype and suggests expressive speech delay, moderate motor delay, learning difficulties/mild ID, mild microcephaly, short stature and notable social behavior deficits as clinical hallmarks. In addition, one patient presented with nephroblastoma. The possible involvement of QRICH1 in pediatric cancer assumes careful surveillance a key priority for outcome of these patients. Further research and enlargement of cohorts are warranted to learn about the genetic architecture and the phenotypic spectrum in more detail.     

Expanding the genotypic spectrum of Jalili syndrome: Novel CNNM4 variants and uniparental isodisomy in a north American patient cohort

Jalili syndrome is a rare multisystem disorder with the most prominent features consisting of cone‐rod dystrophy and amelogenesis imperfecta. Few cases have been reported in the Americas. Here we describe a case series of patients with Jalili syndrome examined at the National Eye Institute's Ophthalmic Genetics clinic between 2016 and 2018. Three unrelated sporadic cases were systematically evaluated for ocular phenotype and determined to have cone‐rod dystrophy with bull's eye maculopathy, photophobia, and nystagmus. All patients had amelogenesis imperfecta. Two of these patients had Guatemalan ancestry and the same novel homozygous CNNM4 variant (p.Arg236Trp c.706C > T) without evidence of consanguinity. This variant met likely pathogenic criteria by the American College of Medical Genetics guidelines. An additional patient had a homozygous deleterious variant in CNNM4 (c.279delC p.Phe93Leufs*31), which resulted from paternal uniparental isodisomy for chromosome 2p22‐2q37. This individual had additional syndromic features including developmental delay and spastic diplegia, likely related to mutations at other loci. Our work highlights the genotypic variability of Jalili syndrome and expands the genotypic spectrum of this condition by describing the first series of patients seen in the United States.     

X‐chromosomal inactivation directly influences the phenotypic manifestation of X‐linked protoporphyria

X‐linked protoporphyria (XLP), a rare erythropoietic porphyria, results from terminal exon gain‐of‐function mutations in the ALAS2 gene causing increased ALAS2 activity and markedly increased erythrocyte protoporphyrin levels. Patients present with severe cutaneous photosensitivity and may develop liver dysfunction. XLP was originally reported as X‐linked dominant with 100% penetrance in males and females. We characterized 11 heterozygous females from six unrelated XLP families and show markedly varying phenotypic and biochemical heterogeneity, reflecting the degree of X‐chromsomal inactivation of the mutant gene. ALAS2 sequencing identified the specific mutation and confirmed heterozygosity among the females. Clinical history, plasma and erythrocyte protoporphyrin levels were determined. Methylation assays of the androgen receptor and zinc‐finger MYM type 3 short tandem repeat polymorphisms estimated each heterozygotes X‐chromosomal inactivation pattern. Heterozygotes with equal or increased skewing, favoring expression of the wild‐type allele had no clinical symptoms and only slightly increased erythrocyte protoporphyrin concentrations and/or frequency of protoporphyrin‐containing peripheral blood fluorocytes. When the wild‐type allele was preferentially inactivated, heterozygous females manifested the disease phenotype and had both higher erythrocyte protoporphyrin levels and circulating fluorocytes. These findings confirm that the previous dominant classification of XLP is inappropriate and genetically misleading, as the disorder is more appropriately designated XLP.     

Scapuloiliac dysostosis (Kosenow syndrome,pelvis‐shoulder dysplasia) spectrum: Three additional cases

We report on 3 patients (2 sibs and an unrelated adult woman) with scapuloiliac dysostosis (Kosenow syndrome, Pelvis‐Shoulder Dysplasia) each of whom has additional abnormalities not previously reported in the literature. The clinical spectrum of this entity is discussed along with possible inheritance patterns. Am. J. Med. Genet. 95:505–515, 2000. © 2000 Wiley‐Liss, Inc.     

Kallmann syndrome in three unrelated women and an association with femur‐fibula‐ulna dysostosis in one case

We describe three unrelated women with hypogonadotropic hypogonadism and anosmia; that is, Kallmann syndrome. Absence of olfactory bulbs and tracts and different degrees of asymmetric dysplasia of olfactory sulci were demonstrated by MRI. Both the father of Case 1 and the maternal aunt of Case 3 had anosmia, thus autosomal dominant inheritance seems to be likely. Patient 2 had Kallmann syndrome and FFU (femur‐fibula‐ulna) dysostosis as a sporadic occurrence in her family. Am. J. Med. Genet. 93:176–180, 2000. © 2000 Wiley‐Liss, Inc.     

A novel SPECC1L mutation causing Teebi hypertelorism syndrome: Expanding phenotypic and genetic spectrum

Only eleven SPECC1L mutations have been reported worldwide which were associated with autosomal dominant oblique facial clefts, Opitz G/BBB Syndrome and Teebi hypertelorism syndrome. In this study, we reported the first Chinese patient with Teebi hypertelorism syndrome. Utilizing whole exome sequencing and Sanger sequencing, we identified a de novo missense mutation NM_015330.3: c.1249A > C, p.(Thr417Pro) in SPECC1L gene. With common manifestations in Teebi hypertelorism syndrome such as special facial appearance, umbilical malformations and congenital heart defects, the patient also had unusual symptoms including recurrent infections, febrile seizures and widely opened anterior fontanelle. Furthermore, all the recorded SPECC1L mutations were analyzed by in silico analysis. Coiled-coil domain 2 was the most frequently mutated domain and positions e and g might be more important than other positions. This paper expanded the phenotypic spectrum of Teebi hypertelorism syndrome and elaborated molecular characteristics of SPECC1L mutations.     

Diagnosis and management of the phenotypic spectrum of twins with Beckwith‐Wiedemann syndrome

Beckwith‐Wiedemann syndrome (BWS) is an overgrowth disorder with a heterogeneous phenotypic spectrum. There is an increased prevalence of monozygotic twinning in BWS. Given the epigenetic nature and phenotypic spectrum that defines BWS, twins are often discordant for clinical features, and clinicians are faced with the challenge of diagnosing and managing these twins. We present a cohort of multiple pregnancies in which one or more child from each pregnancy was diagnosed with BWS. We conducted a chart review of monochorionic and dichorionic gestations. Clinical scores for monochorionic twins demonstrated phenotypic discordance between the proband and twin. Based on linear regression analysis, a higher clinical score in the proband correlated with larger phenotypic discordance between twin siblings. Despite phenotypic discordance, however, we observed a consistent additive clinical score for a pregnancy (proband's plus twin's scores from a pregnancy). This idea of a finite degree of affectedness for a pregnancy implies a finite number of epigenetically affected cells. This further corroborates the idea that timing of monozygotic monochorionic twinning correlates with the disruption of establishment and/or maintenance of imprinting. The difference in clinical score between a proband and their twin may be due to diffused mosaicism, whereby there is an asymmetric distribution of affected cells among the multiple fetuses in a monozygotic monochorionic pregnancy, leading to a spectrum of variably affected phenotypes. Based on these findings, we recommend an algorithm for a conservative approach to clinically evaluate all children in a monozygotic multiple gestation affected by BWS.     

Meta‐analysis of genotype‐phenotype associations in Bardet‐Biedl syndrome uncovers differences among causative genes

Bardet‐Biedl syndrome (BBS) is a recessive genetic disease causing multiple organ anomalies. Most patients carry mutations in genes encoding for the subunits of the BBSome, an octameric ciliary transport complex, or accessory proteins involved in the BBSome assembly or function. BBS proteins have been extensively studied using in vitro, cellular, and animal models. However, the molecular functions of particular BBS proteins and the etiology of the BBS symptoms are still largely elusive. In this study, we applied a meta‐analysis approach to study the genotype‐phenotype association in humans using our database of all reported BBS patients. The analysis revealed that the identity of the causative gene and the character of the mutation partially predict the clinical outcome of the disease. Besides their potential use for clinical prognosis, our analysis revealed functional differences of particular BBS genes in humans. Core BBSome subunits BBS2, BBS7, and BBS9 manifest as more critical for the function and development of kidneys than peripheral subunits BBS1, BBS4, and BBS8/TTC8, suggesting that incomplete BBSome retains residual function at least in the kidney.     

Nager syndrome: confirmation of SF3B4 haploinsufficiency as the major cause

Nager syndrome belongs to the group of acrofacial dysostosis, which are characterized by the association of craniofacial and limb malformations. Recently, exome sequencing studies identified the SF3B4 gene as the cause of this condition in most patients. SF3B4 encodes a highly conserved protein implicated in mRNA splicing and bone morphogenic protein (BMP) signaling. We performed SF3B4 sequencing in 14 families (18 patients) whose features were suggestive of Nager syndrome and found nine mutations predicted to result in loss‐of‐function. SF3B4 is the major gene responsible for autosomal dominant Nager syndrome. All mutations reported predict null alleles, therefore precluding genotype–phenotype correlations. Most mutation‐negative patients were phenotypically indistinguishable from patients with mutations, suggesting genetic heterogeneity.