A de novo splice site mutation in CASK causes FG syndrome-4 and congenital nystagmus.

Mutations in CASK cause X-linked intellectual disability, microcephaly with pontine and cerebellar hypoplasia, optic atrophy, nystagmus, feeding difficulties, GI hypomotility, and seizures. Here we present a patient with a de novo carboxyl-terminus splice site mutation in CASK (c.2521-2A>G) and clinical features of the rare FG syndrome-4 (FGS4). We provide further characterization of genotype-phenotype correlations in CASK mutations and the presentation of nystagmus and the FGS4 phenotype. There is considerable variability in clinical phenotype among patients with a CASK mutation, even among variants predicted to have similar functionality. Our patient presented with developmental delay, nystagmus, and severe gastrointestinal and gastroesophageal complications. From a cognitive and neuropsychological perspective, language skills and IQ are within normal range, although visual-motor, motor development, behavior, and working memory were impaired. The c.2521-2A>G splice mutation leads to skipping of exon 26 and a 9 base-pair deletion associated with a cryptic splice site, leading to a 28-AA and a 3-AA in-frame deletion, respectively (p.Ala841_Lys843del and p.Ala841_Glu868del). The predominant mutant transcripts contain an aberrant guanylate kinase domain and thus are predicted to degrade CASK's ability to interact with important neuronal and ocular development proteins, including FRMD7. Upregulation of CASK as well as dysregulation among a number of interactors is also evident by RNA-seq. This is the second CASK mutation known to us as cause of FGS4. © 2017 Wiley Periodicals, Inc.

Simpson-Golabi-Behmel syndrome: an X-linked encephalo-tropho-schisis syndrome. 1988.

INTRODUCTION: The following paper by Professor GiovanniNeri and colleagues was originally published in 1988, American Journal of Medical Genetics 30:287­299. This paper represented a seminal work at the time of publication as it not only reported a new family with a disorder that had been called the "gigantism-dysplasia syndrome", but also suggested naming the condition the Simpson-Golabi-Behmel syndrome. This eponym has clearly stood "the test of time", and that designation is now widely accepted. This paper is graciously republished by Wiley-Blackwell in the Special Festschrift issue honoring Professor Neri. We report on another family with the so-called "gigantism-dysplasia syndrome", an X-linked condition characterized by pre-and postnatal overgrowth, characteristic face with apparent coarseness, dysplastic changes in several tissues, and mild intellectual impairment. This condition has been called the Golabi-Rosen syndrome; however, we agree that is the same entity as that described, in a milder form, by Simpson et al. in 1975 and by Behmel et al. in 1984. Therefore, we suggest that this entity be designated the Simpson-Golabi-Behmel syndrome. The manifestations in affected individuals suggest that this condition represents an X-linked encephalo-tropho-schisis syndrome.

The cardiofaciocutaneous syndrome.

The cardiofaciocutaneous (CFC) syndrome is a condition of sporadic occurrence, with patients showing multiple congenital anomalies and mental retardation. It is characterised by failure to thrive, relative macrocephaly, a distinctive face with prominent forehead, bitemporal constriction, absence of eyebrows, hypertelorism, downward-slanting palpebral fissures often with epicanthic folds, depressed nasal root and a bulbous tip of the nose. The cutaneous involvement consists of dry, hyperkeratotic, scaly skin, sparse and curly hair, and cavernous haemangiomata. Most patients have a congenital heart defect, most commonly pulmonic stenosis and hypertrophic cardiomyopathy. The developmental delay usually is moderate to severe. The syndrome is caused by gain-of-function mutations in four different genes BRAF, KRAS, mitogen-activated protein/extracellular signal-regulated kinase MEK1 and MEK2, all belonging to the same RAS-extracellular signal-regulated kinase (ERK) pathway that regulates cell differentiation, proliferation and apoptosis. The CFC syndrome is a member of a family of syndromes that includes the Noonan and Costello syndromes, presenting with phenotypic similarities. Noonan syndrome is caused by mutations in the protein tyrosine phosphatase SHP-2 gene (PTPN11), with a few people having a mutation in KRAS. Costello syndrome is caused by mutations in HRAS. The protein products of these genes also belong to the RAS-ERK pathway. Thus, the clinical overlap of these three conditions, which often poses a problem of differential diagnosis, is explained by their pathogenetic relatedness.

"Double-muscle" trait in cattle: a possible model for Wiedemann-Beckwith syndrome.

The Wiedemann-Beckwith syndrome (WBS) was first described in 1963 as a group of anomalies involving primarily macrosomia, macroglossia, and omphalocele. Histologic studies of WBS show nesidioblastosis of the pancreas, adrenocortical cytomegaly, and persistent metanephric blastema of the kidney. Multiple lines of evidence indicate that the human 11p15.5 region is the locus of abnormality in WBS. Insulin-like growth factor II (IGF-2) frequently has been considered a candidate gene, and expression of IGF-2 is known to be significantly delayed in fetal skeletal muscle of double-muscle (DM) cattle. Other candidate genes recently have been proposed for WBS. A number of recessive alleles in the bovine myostatin gene (GDF8, mapped to bovine chromosome 2 and apparently orthologous to the human 2q22 region) have been shown to be responsible for DM. Recently the first human case of deficient GDF8 function has been reported, confirming the importance of this gene. Bovine IGF-2 has been sequenced and localized to chromosome 25. The primary purpose of this study was to compare and contrast histologic findings in DM and WBS. Immunohistochemical staining confirms changes similar to nesidioblastosis in the pancreas. Other dysplastic changes of a cystic nature are seen in the adrenal. The renal histology of DM fetuses did not appear significantly different than controls.

Absence of 12q21.2q22 deletions and subtelomeric rearrangements in cardiofaciocutaneous (CFC) syndrome patients.

Recent publications described two patients with a CFC-like phenotype and the same deletion of chromosome region 12q21.2q22 [Rauen et al., 2000, 2002]. The patients did not have the classical CFC phenotype and presented other signs not usually seen in CFC patients: the first patient had hydrocephalus, and the second, a history of olygohydramnios, normal stature, pyloric stenosis, cutaneous syndactyly of toes and bilateral transverse palmar creases. In order to verify if classic CFC patients with normal chromosomes in conventional preparations have microdeletions within the 12q21.2q22 chromosome region, we performed FISH analysis using 12 BAC probes to screen this area. The average interval between the probes was of approximately 1 Mb. No deletions were found in any of the 17 classical CFC patients we examined. We conclude that the region 12q21.2q22 is not a candidate region for CFC syndrome and that the patients described by Rauen et al. [2000, 2002] probably have a different condition, i.e., an aneuploidy syndrome, with some phenotypic resemblance to the CFC syndrome. To further evaluate the possibility of other chromosome imbalances, we performed a subtelomeric analysis, by FISH technique, of all chromosomes, and did not find any subtelomeric rearrangements.

PTPN11 mutations are not responsible for the Cardiofaciocutaneous (CFC) syndrome.

Cardiofaciocutaneous (CFC) syndrome is a multiple congenital anomalies/mental retardation syndrome characterized by congenital heart defects, characteristic facial appearance, short stature, ectodermal abnormalities and mental retardation. It was described in 1986, and to date is of unknown genetic etiology. All reported cases are sporadic, born to non-consanguineous parents and have apparently normal chromosomes. Noonan and Costello syndromes remain its main differential diagnosis. The recent finding of PTPN11 missense mutations in 45-50% of the Noonan patients studied with penetrance of almost 100% and the fact that in animals mutations of this gene cause defects of semilunar valvulogenesis, made PTPN11 mutation screening in CFC patients a matter of interest. We sequenced the entire coding region of the PTPN11 gene in ten well-characterised CFC patients and found no base changes. We also studied PTPN11 cDNA in our patients and demonstrated that there are no interstitial deletions either. The genetic cause of CFC syndrome remains unknown, and PTPN11 can be reasonably excluded as a candidate gene for the CFC syndrome, which we regard as molecular evidence that CFC and Noonan syndromes are distinct genetic entities.

Megacystis-microcolon-intestinal hypoperistalsis syndrome and aganglionosis in trisomy 18.

Ultrasonography at 23 weeks of gestation documented the presence of megacystis with horseshoe kidney, microcolon, intestinal malrotation, and decreased amniotic fluid volume. After pregnancy termination, an autopsy was performed. The external phenotype was diagnostic of the trisomy 18 syndrome confirmed by chromosome examination. The fetus also had a massively distended bladder with parchment-thin wall, microcolon, intestinal malrotation but no urethral obstruction or hydronephrosis. No ganglion cells were present in the colon or bladder. This has not been mentioned in other reported cases and, therefore, suggests pathogenic heterogeneity. The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare autosomal recessive condition of unknown pathogenesis whose genes map to 15q24. Thus, its previously undescribed presence in trisomy 18 further suggests etiologic heterogeneity.

Meier-Gorlin syndrome: report of eight additional cases and review.

The Meier-Gorlin syndrome or ear, patella, short stature syndrome (MIM 224690) is a rare autosomal recessive disorder, characterized by the association of bilateral microtia, aplasia/hypoplasia of the patellae, and severe pre- and postnatal growth retardation. Twenty-one cases have been reported in literature thus far. Here we report on eight patients from seven families and compare them with previously described cases. One of the present cases had previously undescribed genital anomalies. There is a difference in facial characteristics between patients reported in early infancy and those described at older age; follow-up of patients is needed to substantiate this changing facial phenotype. We recommend radiographic survey of the patellae in patients at older age to investigate the weight of absent or hypoplastic patellae in the diagnosis of the syndrome.

Comments on biological asymmetry.

Gross forms of asymmetry of biological structure, hence of development, are generally considered abnormalities of conformation with "perfect" symmetry, whether bilateral or radial, being regarded as the "ideal" form. This notion, primarily a cultural deceit of neo-Platonic origin, can easily be shown to be wrong or at best only skin-deep by any student of anatomy or surgery who finds the heart not in the midline but, most of the time on the left, liver on the right, gut coiled and disposed in a certain direction with appendix in the right lower quadrant, and so forth. Indeed, since the beginning of Amphioxus, a major effect of evolutionary developmental modification has been the abolition of the visceral symmetry which characterized this cephalochordate with introduction of a specific pattern of asymmetry called laterality determination. This embryonic process, which is beginning to yield its universal molecular basis, is probably not responsible for another type of biological phenomenon designated fluctuating asymmetry well known to anthropologists (on the basis of quantitative studies of morphometric traits of teeth, appendicular skeleton, dermatoglyphics) and well-known to the ancients who in their most beautiful Hellenistic sculptures introduced deliberate asymmetries into facial structure and expression. Photographic images constructed of 2 right or 2 left facial halves may differ to a starling degree from the authentic face (Fig. 1). The relatively random nature of fluctuating asymmetry makes it less likely to be under strong natural selection. 1 Middle panel: Frontal view of face of a normal man. Left panel: "Artificial" face constructed out of two right halves of the same face. Right panel: Face constructed out of two left halves. A careful study of the right and left panels makes it easier to appreciate the actual degree of asymmetry present in the unaltered middle image/face. However, in addition to laterality determination and fluctuating asymmetry, there are additional forms of biological asymmetry which have other biological bases such as Lyonization, somatic/clonal mosaicism, mosaic aneuploidy/polyploidy, chimaerism, and developmental "resistance" seen with especial clarity in virtually every hereditary limb malformation. In this paper we will attempt to enumerate the causal forms and bases of biological asymmetry.

Evidence for the "midline" hypothesis in associated defects of laterality formation and multiple midline anomalies.

A male infant was liveborn at 38 weeks of gestation to a G4P1AB2, 22-year-old, mother. Polyhydramnios and multiple congenital anomalies were noted by ultrasonography; the infant died 5 min after birth. At autopsy, the infant had multiple defects of blastogenesis including midline anomalies with asplenia and abnormalities of laterality formation. The laterality defects were unusual in that they combined asplenia with hypoplastic, symmetrically unilobate lungs and bilateral hyparterial bronchi more consistent with polysplenia, abdominal situs inversus with midline stomach, symmetric liver, and left gallbladder. No intracardiac abnormalities were present, but there was azygous continuation of the inferior vena cava. Additional multiple midline defects included bronchoesophageal fistula, duodenal atresia, absence of posterior leaf of diaphragm; horseshoe adrenal gland; microcephaly; Dandy-Walker anomaly with agenesis of cerebellar vermis and occipital encephalocele; holoprosencephaly with orbital encephalocele, midline defect of the orbital plate of the skull, bilateral anophthalmia, double proboscis with bilateral choanal atresia, midline upper lip and palatal cleft; single-lobed thyroid; hypoplastic external genitalia with midline cleft of scrotum, long tapering fingers, and defects of the cranium at the sites of orbital and occipital encephaloceles. Defects of laterality frequently are associated with other complex midline anomalies, which both result from a disturbance of pattern formation during blastogenesis, i.e., the induction of the progenitor fields. The latter are the result of the establishment of upstream expression domains of growth and transcription factors and other morphogens. Many of these and other genetic systems, expressed asymmetrically around the midline, are responsible for laterality formation and are the result of upstream and subsequent downstream gene expression cascades through the expression of genes such as HOX genes; bFGF; transforming growth factor beta/activins/BMP4; WNT-1,8; and SHH.

Klippel-Feil anomaly with Sprengel anomaly, omovertebral bone, thumb abnormalities, and flexion-crease changes: novel association or syndrome?

We report on a family with Klippel-Feil anomaly (KF), Sprengel anomaly, omovertebral bone, thumb abnormalities, and flexion-crease abnormalities. This combination of abnormalities does not fit into Holt-Oram syndrome, Wildervanck syndrome, oculo-auriculo-vertebral (Goldenhar) anomaly, or the VATER complex. Clinical aspects of a KF classification are discussed. The state of molecular research on KF is briefly reported. We conclude that this set of anomalies is a novel combination, probably representing pleiotropy of a single Mendelian gene.

Human anotocephaly (aprosopus, acrania-synotia) in the Vilnius anatomical collection.

A genetic theory of "multifactorial" malformations, i.e., anomalies of blastogenesis or organogenesis, involving polygenic predisposition with morphogenetic threshold effect, was developed by Sewall Wright in the 1920s and remains an essential basis of birth defects biology. Because of the phenomenon of universality, i.e., the deployment of identical inductive, or pattern-forming, upstream molecular mechanisms during the earliest stages of mammalian morphogenesis, Wright's work on guinea pig otocephaly is highly pertinent to "corresponding," i.e., homologous malformations in humans. This concept is illustrated on the hand of a human fetus in the Vilnius (Lithuania) Pathological Museum with anotocephaly, i.e., anencephaly and otocephaly so severe as to correspond to Wright's guinea pig otocephaly grade 11 or 12. The observation also supports our apology for old museums and old books as repositories for anomalies, no less important for their rarity.

Multiple meningiomas, craniofacial hyperostosis and retinal abnormalities in Proteus syndrome.

Because clinical evidence suggests that Proteus syndrome may be caused by a somatic mutation during early development, resulting in mosaicism, the possible types of abnormalities and their clinical distributions are highly variable. Here, we report on an unusual patient with Proteus syndrome. Manifestations included multiple meningiomas, polymicrogyria, and periventricular heterotopias. Both eyes had epibulbar cystic lesions. The retina showed diffuse disorganization with nodular gliosis, retinal pigmentary abnormalities, chronic papilledema, and optic atrophy. Other abnormalities included progressive cranial, mandibular, maxillary, and auditory canal hyperostoses, epidermal nevi, and mental deficiency. The limbs were proportionate, and the hands and feet were normal.