New manifestations of Neu-Laxova syndrome

Fetal Phenotyping and Whole Exome Sequencing for 12 Egyptian Families With Serine Biosynthesis Defect: Novel Clinical and Allelic Findings With a Founder Effect

OBJECTIVE

The purpose of this study was to improve our understanding of severe serine biosynthesis defects through a comprehensive description of prenatal, and postnatal manifestations and the mutational spectrum in a new cohort of 12 unrelated Egyptian Families.

METHODS

Detailed fetal ultrasound examination, postnatal assessment, and whole exome sequencing (WES) were performed in a cohort of 12 fetuses with suspected Neu-Laxova syndrome (NLS), the most severe expression of serine biosynthesis defects. Additionally, a comprehensive review of the literature was conducted by merging the data from all the molecularly-confirmed cases with ours to gain a better understanding of the clinical variability of NLS.

RESULTS

Novel clinical manifestations including intrauterine convulsions, hemivertebrae, natal teeth, holoprosencephaly, and rhombencephalosynapsis were observed. Molecular analysis identified 7 and 2 likely disease-causing variants in the PSAT1 and PHGDH genes, respectively. Four of them were novel, including the c.734G>A missense variant in PSAT1, which has been proposed to be a founder variant among Egyptians.

CONCLUSION

The present cohort expands the spectrum of serine biosynthesis disorders. Moreover, it illuminates the role of prenatal exome sequencing in lethal conditions constituting the most severe end of already-known human diseases.

Neu Laxova syndrome and megacystis in the first trimester: Broadening the fetal phenotype

Neu Laxova syndrome (NLS) is a rare and lethal congenital disorder characterized by severe intra-uterine growth retardation (IUGR), ichthyosis, abnormal facial features, limb abnormalities with arthrogryposis and a wide spectrum of severe malformations of the central nervous system (CNS). NLS is due to biallelic variants in three genes previously involved in serine-deficiency disorders (PHGDH, PSAT1 and PSPH), extending the phenotypic spectrum of these disorders.

Neu-Laxova's Syndrome: A Case Report of a Fetus with Novel Mutation in PHGDH Gene and a Literature Review

Neu-Laxova's syndrome (NLS) is a rare group of congenital malformations comprising intrauterine growth retardation (IUGR), central nervous system malformations, microcephaly, facial anomalies, ichthyosis, generalized edema, limb abnormalities, polyhydramnios, and perinatal death. We hereby report a fetus at 25 weeks' gestation with IUGR, facial and limb anomalies, and smooth brain detected on antenatal ultrasound and magnetic resonance imaging of fetus and confirmed by autopsy. Next-generation sequencing analysis identified a novel homozygous missense mutation in PHGDH gene. Only 35 cases of NLS with genetic etiology have been reported. This is the first case report of mutation in PHGDH from India.

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.

Spina Bifida: Pathogenesis, Mechanisms, and Genes in Mice and Humans

Spina bifida is among the phenotypes of the larger condition known as neural tube defects (NTDs). It is the most common central nervous system malformation compatible with life and the second leading cause of birth defects after congenital heart defects. In this review paper, we define spina bifida and discuss the phenotypes seen in humans as described by both surgeons and embryologists in order to compare and ultimately contrast it to the leading animal model, the mouse. Our understanding of spina bifida is currently limited to the observations we make in mouse models, which reflect complete or targeted knockouts of genes, which perturb the whole gene(s) without taking into account the issue of haploinsufficiency, which is most prominent in the human spina bifida condition. We thus conclude that the need to study spina bifida in all its forms, both aperta and occulta, is more indicative of the spina bifida in surviving humans and that the measure of deterioration arising from caudal neural tube defects, more commonly known as spina bifida, must be determined by the level of the lesion both in mouse and in man.

[Neu-Laxova syndrome: Three case reports and a review of the literature]

INTRODUCTION

The Neu-Laxova syndrome (NLS) is a rare autosomal recessive and early lethal disorder. It is characterized by severe intra-uterine growth retardation, abnormal facial features, ichthyotic skin lesions and severe central nervous system malformations, especially microlissencephaly. Others characteristic features associated with fetal hypokinesia sequence, including arthrogryposis, subcutaneous edema and pulmonary hypoplasia, are frequently reported in NLS.

PATIENTS AND METHODS

The clinicopathological characteristics of NLS are described in three cases with striking prenatal diagnostic findings and detailed post-mortem examinations. A review of the literature is undertaken with a focus on molecular basis.

RESULTS

We present three new patients with NLS: one stillbirth male and two female newborns, delivered at 29, 35 and 40 weeks of gestational age, respectively. Characteristic ultrasound findings included hydramnios, severe intra-uterine growth restriction, craniofacial and cental nervous system anomalies. The cytogenetic study, performed in one case, was normal. The post-mortem examination revealed characteristic abnormalities in all three cases, that allowed to make a prompt diagnosis of the NLS. Data from these patients suggest that the NLS represents a heterogeneous phenotype. This feature has been highlighted in the literature.

CONCLUSION

The SNL is a lethal developmental disorder characterized by phenotypic heterogeneity with striking neurological defects. It is underpinned by genetic heterogeneity. It can be caused by mutations in all three genes involved in de novo L-serine biosynthesis: PHGDH, PSAT1 and PSPH. Hence, the NLS constitutes the most severe end of already known human disease, i.e. serine-deficiency disorder.

Identification of a premature stop codon mutation in the PHGDH gene in severe Neu-Laxova syndrome-evidence for phenotypic variability

In some cases Neu-Laxova syndrome (NLS) is linked to serine deficiency due to mutations in the phosphoglycerate dehydrogenase (PHGDH) gene. We describe the prenatal and postnatal findings in a fetus with one of the most severe NLS phenotypes described so far, caused by a homozygous nonsense mutation of PHGDH. Serial ultrasound (US) and pre- and postnatal magnetic resonance imaging (MRI) evaluations were performed. Prenatally, serial US evaluations suggested symmetric growth restriction, microcephaly, hypoplasia of the cerebellar vermis, micrognathia, hydrops, shortened limbs, arthrogryposis, and talipes equinovarus. The prenatal MRI confirmed these findings prompting a diagnosis of NLS. After birth, radiological imaging did not detect any gross bone abnormalities. DNA was extracted from fetal and parental peripheral blood, all coding exons of PHGDH were PCR-amplified and subjected to Sanger sequencing. Sequencing of PHGDH identified a homozygous premature stop codon mutation (c.1297C>T; p.Gln433*) in fetal DNA, both parents (first-cousins) being heterozygotes. Based on previous associations of mutations in this gene with a milder NLS phenotype, as well as cases of serine deficiency, these observations lend further support to a genotype-phenotype correlation between the degree of PHGDH inactivation and disease severity.

Rare manifestations of Neu-Laxova syndrome

Neu-Laxova syndrome is a rare lethal congenital disorder involving multiple systems. Intrauterine growth retardation, ichthyosis, microcephaly, abnormal facial findings and limb contractures are its key features. We present a stillborn female baby of 1.5 kg with characteristic features including growth retardation, microcephaly, severe ectropion, micrognathia, flattened nose, eclabion, large ears, puffy hands and feet. In addition to these features, lissencephaly, severely hypoplastic cerebrum and corpus callossum, Dandy-Walker malformation, Transposition of Great Vessels and hepatomegaly were noted at autopsy. The patient was born at 38 weeks of gestation to consanguineous (second degree) Indian parents. The mother was 26 year old second gravida with lack of prenatal followup. Therefore, the condition was diagnosed postnatally. Because of the autosomal recessive inheritence of Neu-Laxova syndrome, in countries with high rates of consanguineous marriage, serial prenatal ultrasound examinations with genetic counseling should be performed on pregnant women at high risk to offer termination of affected pregnancies.

A spectrum of phenotypical expression OF Neu-Laxova syndrome: Three case reports and a review of the literature

Neu-Laxova syndrome is a rare autosomal recessive disorder characterized by severe intra-uterine growth restriction, extreme microcephaly, marked edema with skin restriction, ichthyosis, craniofacial anomalies, limb deformities, and a spectrum of central nervous system malformations. Less than 70 cases have been described since the first report in 1971. To this day the etiology and genetic basis remains unknown. Consanguinity has been reported. Some authors have postulated the syndrome to be a form of neuro-ectodermal dysplasia, while others suggest that it is a malformation syndrome secondary to severe skin restriction. Although the outcome of this syndrome is lethal, a single case of longer survival (6 months) has been reported. The majority of cases are stillborn or die shortly after birth. Thus, it is clear that Neu-Laxova exhibits a spectrum of disease, with varying degrees of phenotypic expression. We are presenting three new cases of Neu-Laxova syndrome; two were stillbirths and one lived for eleven weeks. Our microscopic and post-mortem findings in these three cases display the vast spectrum of this rare syndrome.

Neu?Laxova syndrome: a case report and review of the literature

Neu-Laxova syndrome (NLS) is a rare autosomal recessive syndrome, characterized by severe intrauterine growth retardation (IUGR), microcephaly, abnormal brain development, oedema and ichthyosis. It was first reported in 1971 by Neu et al. (Pediatrics 47: 610-612) and since then no more than 60 cases have been reported. A newborn girl delivered from a 29-year-old healthy mother was admitted to hospital with a thick membrane covering her body and dismorphic appearance. The diagnosis of NLS was made according to characteristic features. The syndrome is known to have a poor prognosis and the baby lived for 9 weeks. This case is one of the longest living cases of NLS and the fourth case reported from Turkey.

A rare cause of polyhydramnios: Neu-Laxova syndrome

Neu-Laxova syndrome is a rare group of congenital malformations including intrauterine growth retardation (IUGR), microcephaly, central nervous system alterations, facial abnormalities, ichthyosis, limb abnormalities, generalized edema, polyhydramnios, and perinatal death. Thirty cases have been identified since the publication of the first two cases and only five of them had a prenatal diagnosis. The earliest diagnosis in a published case was at week 32 of gestation. This study illustrates that the detection of the syndrome during the second trimester of gestation is possible, with emphasis on the detection of the early appearance of polyhydramnios and the association of the syndrome with the Arabic ethnic group.

Evaluation of a Fetus with Neu-Laxova Syndrome through Prenatal, Clinical, and Pathological Findings

We report a case of Neu-Laxova syndrome in a fetus at 22 weeks with the ultrasonographic findings of characteristic facial findings, limb contractures, kyphosis and polyhydramnios. Pathological and ultrasonographic studies are discussed.

Neu-Laxova syndrome: detailed prenatal diagnostic and post-mortem findings and literature review

Neu-Laxova syndrome (NLS) is a lethal, autosomal recessive multiple malformation syndrome with many features resulting from severe skin restriction and decreased fetal movement. It is characterized by ichthyosis, marked intrauterine growth restriction (IUGR), microcephaly, short neck, central nervous system (CNS) anomalies, limb deformities, hypoplastic lungs, edema, and abnormal facial features including severe proptosis with ectropion, hypertelorism, micrognathia, flattened nose, and malformed ears. We present two new patients with NLS with striking prenatal diagnostic findings and detailed post-mortem examinations and review the previously described cases in the literature. Data from these patients suggest that the NLS represents a heterogeneous phenotype. Prenatal ultrasound findings of marked ocular proptosis in a growth restricted, edematous fetus should prompt consideration of a diagnosis of the NLS.

Second trimester diagnosis of Neu Laxova syndrome

This is the first report of a prenatally diagnosed case of Neu Laxova syndrome (NLS) from India. This also includes a case of NLS in monochorionic diamniotic twins and two more cases in which we were able to detect most of the features of NLS as early as 19 to 20 weeks by routine antenatal ultrasonography. Severe intrauterine growth retardation (IUGR), microcephaly, central nervous system (CNS) abnormality, joint contractures, and abnormal facies are the major diagnostic features observed in prenatal ultrasonography. Risk factors such as consanguinity and history of intrauterine death or stillbirth in siblings have been noted in all the cases, but none of the three families that were reported had previously had an affected fetus. The spectrum of skin manifestations and frequency of occurrence of major clinical features of the syndrome have been discussed. Review of the literature on NLS and possibility of detecting the syndrome in the second trimester is discussed.

Neu-Laxova syndrome: a case report

Neu-Laxova syndrome is a rare congenital disorder characterized by microcephaly, limb contactures, lissencephaly and ichthyosis. A case of Neu-Laxova syndrome is presented, with a discussion of clinical manifestations, complications, and therapeutic interventions.

Cerebro-osseous-digital syndrome: four new cases of a lethal skeletal dysplasia--distinct from Neu-Laxova Syndrome

Neu-Laxova Syndrome (NLS) is a severe disorder with intrauterine growth retardation, edema, and characteristic face (including microcephaly with receding forehead, protuberant eyes, a flattened nose, deformed ears, cleft palate, and micrognathia). Ichthyosis is often present. Limb anomalies include hypoplastic fingers and syndactyly of fingers and toes. Patients are usually stillborn or die shortly after birth. We report five unrelated patients--four with atypical NLS and one with typical NLS. All five patients were stillbirths. Clinically, the atypical NLS patients showed a large skull; rhizo-, meso-, and acromelia; and hypoplasia of the metacarpals and phalanges. The feet were similarly affected. Radiographically, the atypical patients showed interpediculate narrowing and hypoplastic vertebral bodies. The long bones were stick-like, showing diaphyseal widening that spared the metaphyses and was more pronounced in the lower extremities. The ilia had a half-moon configuration with widening of the sacrosciatic notches. The ischia were vertical and the pubic bone was absent. The typical NLS patient showed microcephaly, normal vertebral body, and long bone ossification, but a pelvic configuration similar to that of the atypical NLS patients. The common and distinguishing clinical and radiographic features are reviewed. Scott et al. [1981: Am J Med Genet 9:165-175] described two patients with NLS with radiographic and clinical findings similar to patients 1-4 reported here. Patients 1-4 of this report lack the typical findings of NLS and likely represent a distinct lethal skeletal dysplasia.

Prenatal diagnosis of Neu-Laxova syndrome: a case report

BACKGROUND: Neu-Laxova syndrome is a rare congenital abnormality involving multiple systems. We report a case of Neu-Laxova syndrome (NLS) diagnosed prenatally by ultrasound examination. CASE PRESENTATION: A 29-year-old gravida 3, para 2 woman was first seen in our antenatal clinic at 38 weeks' pregnancy. Except for the consanguinity and two previous abnormal stillborn babies her medical history was unremarkable. On ultrasound examination microcephaly, flat forehead, micrognathia, intrauterine growth restriction, generalized edema of the skin, hypoplastic chest, excessive soft tissue deposition of hands and feet, joint contractures and a penis without scrotal sacs were detected. She delivered a 2000 g male fetus. He died five minutes after delivery. Postmortem examination confirmed the diagnosis of Neu-Laxova syndrome. CONCLUSION: Because of the autosomal recessive inheritance of Neu-Laxova syndrome genetic counseling and early-serial ultrasound examination should be performed at risk families. Early diagnosis of the disease may offer termination of the pregnancy as an option.

Early ultrasound diagnosis of Neu-Laxova syndrome

We report the mid-trimester prenatal diagnosis of Neu-Laxova syndrome (NLS) in two at risk families utilizing serial sonographic examinations. Ultrasound and pathologic findings from seven affected pregnancies, the largest case series of NLS to date, are presented. One fetus had anencephaly and incomplete rachischisis, an anomaly that has not been previously reported in association with NLS. Ultrasonographic detection of severe intrauterine growth restriction (IUGR), abnormally postured limbs, microcephaly, and edema allowed prenatal diagnosis of NLS in five of these at risk pregnancies during the mid-trimester. Growth curves derived from serial sonograms reveal abnormalities of all standard biometric measurements. The growth discrepancy was most pronounced in the measurements of the biparietal diameter, which were consistently less than two standard deviations below the mean across all gestational ages. This case series confirms that aberrant growth and anomalies may be detected sufficiently early in gestation to permit prenatal diagnosis of NLS.

A Japanese case of Neu-Laxova syndrome

A 5-day-old Japanese female with Neu-Laxova syndrome was presented. The patient had severe edema throughout the body, desquamation, and erosion of the skin. She also exhibited microcephaly, exophthalmos, and rocker-bottom feet. Histologic examinations of a cutaneous specimen showed atrophy of the dermis and absence of the sebaceous glands. These represent embryonic abnormalities. Even though there was no hypoplasia of the cerebellum and lungs or hydramnios, we evaluated this patient as the first Japanese case of this sporadic disease. With intensive care, including dermatological treatment, the patient survived for 134 days.

Neu-Laxova syndrome: pathological evaluation of a fetus and review of the literature

Neu-Laxova syndrome is a rare autosomal recessive disorder characterized by ichthyosis, intrauterine growth retardation, microcephaly, short neck, central nervous system abnormalities, hypoplastic or atelectatic lungs, limb deformities, edema, polyhydramnios, and short umbilical cord. Abnormal facial features include sloping forehead, hypertelorism, severe ectropion, proptosis, malformed ears, flat nose, and micrognathia. A necropsy study of a male infant with Neu-Laxova syndrome is described. Cleft palate and ambiguous external genitalia were present in addition to anomalies characteristic of Neu-Laxova syndrome. The clinical manifestations are compared with those of the 40 previously reported cases.

Fetal akinesia/hypokinesia sequence: prenatal diagnosis and intra-familial variability

Intrauterine fetal movement plays a key role in normal embryonic and fetal development (Moessinger, 1983). When movement is absent or decreased, abnormal development takes place which can be appreciated in newborns and/or fetuses with the fetal akinesia/hypokinesia sequence. This sequence is caused by a number of heterogeneous entities which result in decreased fetal movements by the action of intrinsic or extrinsic factors. Prenatal diagnosis of the akinesia/hypokinesia sequence may be possible during the second trimester through the use of real-time ultrasonographic evaluation of fetal movement. We report a family with three consecutive affected pregnancies in which the prenatal presentation of this sequence varied. Based on the phenotypic findings of the three affected fetuses, we believe that although they superficially resemble those features found in the New-Laxova syndrome, they are probably affected with a distinctly different lethal form of akinesia/hypokinesia transmitted in an autosomal recessive fashion.

Neu-Laxova syndrome: report of a case from Turkey

We describe a case of Neu-Laxova syndrome in a newborn female who was born at full-term to consanguineous Turkish parents. The pathological and radiological features are described.

Neu Laxova syndrome in two Egyptian families

We report on 2 Egyptian girls from 2 families with 8 affected relatives, 4 in each family. The 2 propositae had unusual facial appearance, severe microcephaly, generalized edema, contractures of limbs, and generalized ichthyotic skin lesions. Findings in the present 2 patients were compared with those in previously reported cases of Neu Laxova syndrome. In our cases, consanguinity, affected sibs, and affected cousins were noted. Autosomal recessive inheritance and lethality are emphasized. A high frequency of the Neu Laxova syndrome in Egyptians is suspected as a result of the increased consanguinity rate.