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

Prenatal Diagnosis of Neu–Laxova Syndrome

Neu–Laxova syndrome is a rare and lethal genetic disease with autosomal recessive inheritance involving abnormalities of multiple systems. It was first reported in 1971. Since then, just eighty-eight cases have been reported. The syndrome is characterized by early and severe growth restriction, and craniofacial anomalies, such as microcephaly, hypertelorism and other malformations, resulting in quite characteristic features. Additionally, it might appear as generalized edema, flexion contractures and other malformations of the extremities, abnormalities in the CNS (central nervous system), skin (severe ichthyosis), and genitourinary and cardiac abnormalities. We present the case of a patient who had her first pregnancy with a fetus with Neu–Laxova syndrome diagnosed in our center during the second-trimester ultrasound. The ultrasound findings suggested the diagnosis, which was confirmed with a genetic study of the amniotic fluid: the variant of the PSAT1 gene, associated with NLS (Neu–Laxova syndrome) 2 in homozygosis. Moreover, there was a second pregnancy with a fetus carrying the same mutation in heterozygosis. In addition, we have carried out a review of published literature about this disease up to the present time.

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.

Clinical, molecular, and pathological findings in a Neu-Laxova syndrome stillborn: A Brazilian case report

Neu-Laxova syndrome (NLS) is a lethal genetic multiple congenital anomaly syndrome of unknown prevalence representing the severe spectrum of serine biosynthesis defects associated with PHGDH, PSAT1, or PSP gene mutations. The purpose of this study was to describe clinical/molecular and pathologic features of a NLS case caused by novel heterozygous missense variant in PHGDH gene identified in his consanguineous parents.

[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 collodion baby with facial dysmorphism, limb anomalies, pachygyria and genital hypoplasia: a mild form of Neu-laxova syndrome or a new entity?

Neu-Laxova syndrome is a rare, lethal, autosomal recessive disorder characterized by intrauterine growth retardation, central nervous system anomalies, skin findings, such as ichthyosis, edema, collodion baby and harlequin fetus, facial dysmorphic features, limb anomalies and genital hypoplasia. Although it is generally a lethal condition, cases of such patients who lived beyond 6 months and 10 months of age have been reported. Here, we describe an 8-year-old boy who was born with collodion membrane, facial dysmorphic features, limb anomalies, genital hypoplasia and pachygyria. He had no major health problems over the course of 8 years of follow-up, except for mild mental/motor retardation, ichthyosis, facial dysmorphic features and limb anomalies. Based on these features, we suggest that because Neu-Laxova syndrome represents a heterogeneous phenotype, our case may be a milder variant of this syndrome or a new genetic entity.

A case of the Neu-Laxova syndrome

Neu-Laxova syndrome is a rare lethal genetic disorder characterized by multiple congenital abnormalities, microcephaly and ichthyosiform skin lesions. The authors describe a case of this syndrome in a newborn baby.

Prenatal diagnosis and postmortem findings of Neu-laxova syndrome

Neu-laxova syndrome is a lethal, autosomal recessive condition associated with ectodermal abnormalities and other characteristic features, including microcephaly, marked intrauterine growth restriction, limb deformities, central nervous system malformations and abnormal facial features, consisting of severe proptosis with ectropion, hypertelorism, micrognathia, flattened nose, malformed ears, and gaping mouth. Here we present a fetus having a dysmorphic face with proptotic eyes, retracted eye lids, depressed nasal bridge and micrognathia at 25 weeks of gestation. The extremities were contracted and no fetal movements were observed during the ultrasonographic examination. The fetus also had microcephaly and the amniotic fluid was increased. The pregnancy was terminated and the abnormalities demonstrated on prenatal ultrasound were confirmed at autopsy.

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.