Neu-Laxova syndrome: pathological, radiological, and prenatal findings in a stillborn female

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'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.

Putting It All Together: Postmortem Diagnosis of a Rare Ichthyosis Syndrome

Neu-Laxova syndrome (NLS) is a rare lethal disorder with autosomal recessive inheritance and is characterized by multiple congenital anomalies. Our case of NLS presented with severe intrauterine growth restriction (IUGR), abnormal facial features, severe central nervous system malformations, skeletal muscle contractures, and the hallmark signs of NLS: ichthyotic skin and excessive subcutaneous tissue with edema. Additionally, testing amniotic fluid from a prior pregnancy with a fetus showing similar abnormalities revealed several regions of homozygosity; one of these regions involved chromosome 1p13.2-p11.2, where the PHGDH gene is located. Based on the pattern of findings on serial fetal ultrasounds, postmortem neonatal exams, gross and microscopic exams, radiographs, and genetic analysis in conjunction with the clinical history and the prior pregnancy with the above-described molecular alteration, a final diagnosis of NLS was made. This rare developmental disorder is characterized by heterogenous neuroectodermal defects. Fetal ultrasound in the second trimester can help diagnose it. It is postulated to be caused by loss-of-function mutations in the PHGDH (phosphoglycerate dehydrogenase), PSAT1 (phosphoserine aminotransferase 1), and PSPH (phosphoserine phosphatase) genes, which are responsible for de novo L-serine synthesis.

Neu-Laxova syndrome presenting prenatally with increased nuchal translucency and cystic hygroma: The utility of exome sequencing in deciphering the diagnosis

Neu-Laxova syndrome (NLS) is a lethal autosomal recessive microcephaly syndrome associated with intrauterine growth restriction (IUGR) and multiple congenital anomalies. Clinical features include central nervous system malformations, joint contractures, ichthyosis, edema, and dysmorphic facial features. Biallelic pathogenic variants in either the PHGDH or PSAT1 genes have been shown to cause NLS. Using exome sequencing, we aimed to identify the underlying genetic diagnosis in three fetuses (from one family) with prenatal skin edema, severe IUGR, micrognathia, renal anomalies, and arthrogryposis and identified a homozygous c.1A>C (p.Met1?, NM_006623.3) variant in the PHGDH gene. Loss of the translation start codon is a novel genetic mechanism for the development of NLS. Prenatal diagnosis of NLS is challenging and few reports describe the fetal pathology. Fetal neuropathologic examination revealed: delayed brain development, congenital agenesis of the corticospinal tracts, and hypoplasia of the hippocampus, cerebellum and brainstem. Each pregnancy also showed increased nuchal translucency (NT) or cystic hygroma. While NLS is rare, it may be a cause of recurrent increased NT/cystic hygroma. This finding provides further support that cystic hygroma has many different genetic causes and that exome sequencing may shed light on the underlying genetic diagnoses in this group of prenatal patients.

[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.

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.

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.

The spectrum of type III lissencephaly: a clinicopathological update

A third type of lissencephaly that does not fufil diagnostic criteria of type I ("classical") and type II ("cobblestone") lissencephaly was described by our group as a new entity identified as OMIM 601160. This lethal familial syndrome comprises micrencephaly/lissencephaly and a spectrum of abnormalities lined to a severe fetal akinesia deformation sequence. Neuropathological findings suggest severe neurodegeneration leading to a marked neuronal dropout of the entire central nervous system and atrophy. Similar neuropathological findings have been described in the Neu-Laxova syndrome (NLS), an apparently different lethal malformation syndrome. Neuropathological similarities between OMIM 601160 and NLS raise the question of clinicopathological variability and genetic heterogeneity of type III lissencephaly. To answer this question, we compared our clinicopathological findings in a series of fetuses with OMIM 601160 to pathological data reported in NLS. In the study, 5 unrelated families with 7 affected fetuses were included. Interestingly, we found striking clinicopathological similarities between OMIM 601160 and NLS, which may represent a variability of a single neurodegenerative disease with early prenatal onset. Molecular studies in multiplex families defined through detailed clinicopathological screening are needed to clarify the distinction, if any, between these two entities.

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.

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 second trimester prenatal diagnosis of Neu-Laxova syndrome

Neu-Laxova is a rare, uniformly lethal, autosomal recessive condition with characteristic limb posturing, facial dysmorphic features, and central nervous system abnormalities. Forty-two cases of Neu-Laxova syndrome have been reported, with only four of these diagnosed prenatally. Three of the four cases were diagnosed at or after 32 weeks' gestation. The fourth case was diagnosed at 22 weeks' gestation in a patient who was followed with serial ultrasound studies due to having a prior affected child. At 19 weeks' gestation, we present the earliest reported prenatal diagnosis of Neu-Laxova syndrome in a primigravida with a non-informative family history.

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.

Lissencephaly type III, stippled epiphyses and loose, thick skin: a new recessively inherited syndrome

We report on two new cases of syndromic lissencephaly in two consanguineous sibs, with skeletal abnormality, born to young, healthy, second cousin parents with healthy children. In Case 1, fetal ultrasound screening at 32 weeks of gestation showed microcephaly, skin infiltration and equinovarus feet. MRI disclosed cerebral agyria, hypoplastic cerebral mantle and posterior agenesis of the corpus callosum. The propositus, a boy, died soon after birth at term. In Case 2, fetal ultrasound study performed at 16 weeks of gestation disclosed skin infiltration. MRI at 22 weeks of gestation showed microcephaly with agenesis of corpus callosum and cerebellar hypoplasia. Pregnancy was terminated at 22 weeks of gestation. The fetus had normal 46, XY karyotype and similar anomalies found in the index case, with cranio-facial edema and arthrogryposis. X-ray films showed epiphyseal stippling of cervical vertebrae, feet and sacrum. Metacarpal bones were shortened with hypoplastic distal phalanges. Neuropathological findings were concordant with the pattern described in type III lissencephaly: an agyric brain with hypoplastic brain stem and cerebellum, severe neuronal loss of the cortical plate, matrix zone, basal ganglia, brainstem nuclei and spinal cord with axonal swelling and microcalcification. This entity seems to be a new syndromic lissencephaly type III, because of epiphyseal calcifications and metacarpophalangeal bone dysplasia.

Fetal akinesia

Normal fetal growth and development during pregnancy is highly dependent upon adequate fetal movement. Limitation of movement, regardless of the underlying cause, can result in a particular pattern of abnormal fetal morphogenesis. This phenotype is termed the fetal akinesia deformation sequence (FADS). The etiology of fetal akinesia may be generally classified into one of five categories: neuropathy, myopathy, restrictive dermopathy, teratogen exposure, or restricted movement due to intrauterine constraint. In this article, the differential diagnosis of fetal akinesia is systematically reviewed and information regarding prenatal diagnosis, prognosis, perinatal management, and recurrence risks are discussed.

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: prenatal ultrasonographic diagnosis, clinical and pathological studies, and new manifestations

A diagnosis of the Neu-Laxova syndrome (NLS) was made by ultrasonography at 32 wks of gestation. Ultrasonographic examination showed intrauterine growth retardation (IUGR), Dandy-Walker anomaly, choroid plexus cysts, receding forehead and microcephaly, bilateral cataract without prominent eyes, scalp edema with no generalized edema, retrognathia, curved penis, and flexion deformities of limbs. The findings in this case are consistent with NLS; however, they did not fit any of Curry's [1982] groups. Massive swelling of hands and feet were among the main manifestations in classic NLS cases. In the case presented herein, edema was noted only in the scalp. This might shed further light on the question of variability vs. heterogeneity in the NLS. This case shows the existing possibility of an early diagnosis of NLS and adds Dandy-Walker anomaly and choroid plexus cysts as new findings to this syndrome.