A case of the Neu-Laxova syndrome: prenatal ultrasonographic monitoring in the third trimester and the histopathological findings

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: 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.

Changes in fetal motility as a result of congenital disorders: an overview

After 35 years of real-time two-dimensional sonography, can we now identify changes in fetal motility indicative of malfunction of the central nervous system in high-risk pregnancies? A literature search on motor assessment procedures (movements specified for body part (SMP), quantity, quality and behavioral state), and motor milestones obtained per fetus (with various congenital disorders) yielded 48 articles describing motility of 104 fetuses. In 67%, SMPs (especially isolated arm or leg movements, breathing and general movements) were assessed. Quantitative aspects were examined in 76%, qualitative aspects in 62% and behavioral states in two fetuses. Abnormal motility can be divided into two main subcategories: hypo- and hyperkinetic, demonstrating decreased variation in qualitative performance (reduced or increased, respectively, amplitude, speed and number of participating body parts, abnormal quantity (reduced or increased, respectively) and reduced differentiation into SMPs. Posture was affected in 40/60 hypokinetic and 4/44 hyperkinetic moving fetuses. The majority of the disorders resulted in an adverse outcome. Fourteen percent survived with a handicap, depending on the underlying disorder. The 16 disorders with hypokinetic motility had mainly an autosomal recessive etiology with no possibility of invasive prenatal diagnosis or conclusive sonographic structural anomalies, in contrast to the 17 disorders with hyperkinetic motility. Within the limitations of the studies, a deeper understanding of affected milestones in motor development can be obtained. Broadening motor assessment procedures from quantitative only to include qualitative aspects, differentiation of SMPs and behavioral states and emphasizing onset and continuity of motility before and after birth will enhance the reliability and predictive value of motility as a parameter in the assessment of fetal condition.

Neu-Laxova syndrome, grossly appearing normal on 20 weeks ultrasonographic scan, that manifested late in pregnancy: a case report

INTRODUCTION

Neu-Laxova syndrome (NLS) is a very rare and extremely lethal syndrome almost always inherited by autosomal recessive pattern.

CASE PRESENTATION

A 21-year-old G2 P1 L0 Turkish woman was first seen at 18 weeks of gestation in antenatal policlinic. On ultrasound examination performed at 20 weeks of gestation for excluding gross abnormalities showed no abnormality and biometry of the fetus was concordant with date of gestation. She stopped follow-up after then. The woman were presented to emergency unit with a complaint of absent fetal movements at 38 weeks of gestation. Multiple abnormalities consistent with NLS have been seen on sonography. Nonvisible gastric cavity was also seen on sonography. Postmortem examination by genetics specialists confirmed the diagnosis of NLS.

CONCLUSION

Neu-Laxova syndrome must be monitored continuously from the beginning of gestation to third trimester via serial ultrasonographies that is focused on previously described features of syndrome especially for consanguineous couples with or without a previous affected fetus.

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.

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.

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.

Prenatal sonographic diagnosis of Neu-Laxova syndrome

We report the sonographic diagnosis of Neu-Laxova syndrome in a fetus at 27 weeks' menstrual age. The parents were first cousins. Sonography revealed microcephaly, a sloping forehead, exophthalmos, a small thorax and abdomen, hypoplastic lungs, syndactyly, hyperextended knees, polyhydramnios, a small placenta, and intrauterine growth restriction. The long bones were normal. The calvaria was hyperechoic and associated with shadowing, obscuring any intracranial abnormalities. This sonographic finding was presumed to represent calvarial calcification, not previously described with this syndrome. We believe that Neu-Laxova syndrome can be reliably diagnosed prenatally by demonstrating the sonographic features described, although other conditions with similar sonographic features need to be considered in the differential diagnosis.

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.

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.

Antley-Bixler syndrome: description of two patients

The Antley-Bixler syndrome comprises malformations of cartilage and bone. The essential signs are a dysmorphic facies with flattening of the central region of the face, humeroradial synostosis with flexed attitude of the upper limbs and swelling of the distal interphalangeal and metacarpophalangeal articulations. Congenital atresia of the nasal choanae, which is often present, makes the prognosis of this syndrome extremely severe. Two patients affected by the syndrome are described. Atresia of the nasal choanae was absent in both. The first patient had genital ambiguity, a condition which has been described in the literature in only two other cases; the second one had all the fundamental characteristics of the syndrome except for humeroradial synostosis, although hypoplasia of the lateral condyle of the humerus and dislocation of the radius are present in association with synostosis between the 2nd metatarsal and the intermediate cuneiform.

Isolated lissencephaly: report of four patients from two unrelated families

Lissencephaly is a brain malformation manifested by a smooth cerebral surface and caused by incomplete neuronal migration. Clinical sequellae include minor craniofacial changes (bitemporal hollowing, small jaw), severe mental retardation, and other neurological abnormalities. Patients with classical or type I lissencephaly and its sequellae but no other significant anomalies are classified as having isolated lissencephaly sequence. Possible causes of isolated lissencephaly sequence include ischemia or viral infection during the time of neuronal migration, microdeletion within the Miller-Dieker syndrome critical region in chromosome band 17p13.3, and Mendelian inheritance. The last is based on a report of a single family with three affected children in 1933. We report four patients with isolated lissencephaly sequence from two unrelated families who provide further support for autosomal (or possibly X-linked) recessive inheritance. In the first family, three brothers were affected. In the second, the parents are first cousins.

Cerebral abnormalities in the Neu-Laxova syndrome

Cerebral abnormalities are considered an obligatory manifestation of the Neu-Laxova syndrome and include lissencephaly, severe microcephaly, aplasia of the corpus callosum, hypoplasia of the cerebellum, and other pathological changes. We present data on 3 cases with central nervous system anomalies, two of which have not been described previously, and summarize the literature on the subject. The problem of distinguishing type III lissencephaly is discussed.

Prenatal diagnosis of a new syndrome: holoprosencephaly with hypokinesia

Markedly decreased fetal activity (akinesia/hypokinesia) is usually readily apparent to experienced mothers, and frequently this concern leads to attempts at prenatal diagnosis. We report prenatal diagnosis of two fetuses with congenital contractures, markedly decreased fetal movement, and microcephaly due to severe holoprosencephaly. Such familial recurrence to phenotypically normal parents suggests a newly recognized autosomal recessive or X-linked syndrome that is readily detectable by prenatal ultrasonography.