Neu-Laxova syndrome: a case report

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.

[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.

[Cutaneous fissures in collodion babies: incidence and treatment]

BACKGROUND

Collodion baby syndrome (CBS) is a pathological cutaneous condition present at birth and is due to the presence of a thick horny layer of the skin. Exfoliation begins early with drying and cracking of the collodion membrane. The cracks may either remain superficial or they may be deeper and affect the superficial dermis, in which case, fissures form. This study of CBS provides information on the clinical aspect of fissures, their incidence, their pathological consequences and therapeutic approaches.

PATIENTS AND METHODS

In our study, diagnosis of CBS was made clinically based on the presence of neonatal collodion membrane. Identification of typical cracks and fissures was made on clinical examination and their site, chronology and consequences were assessed. Routine bacteriological examination of fissures was performed twice weekly on a clinically infected specimen taken from an inguinal fissure. The therapeutic protocol for CBS has been validated and involved use of sterile vaseline oil. Fissures were disinfected.

RESULTS

Cracks are a constant feature. Fissures were seen in 20 of the 33 cases of CBS with the site of predilection being large skinfolds. Morphine was necessary for pain relief in three cases. Pathogenic organisms were isolated in all cases of inflammatory fissures. Dissemination of septicaemia was confirmed in four cases and the offending organism was isolated from the inflammatory fissures in all cases. Candida albicans was present in all cases of fissures in the inguinal folds or between the buttocks. Keratotic adhesions occurred after healing of digital fissures and a surgical procedure was required in this event.

DISCUSSION

Fissures are lesions occurring secondarily to cracks and they were seen in 20 of the 33 cases of CBS. These secondary lesions are rarely mentioned in the literature and the reasons for this oversight are discussed. Fissures are potential complications in all states of CBS, particularly where the collodion is thick. Topical treatment does not prevent transformation of cracks to fissures in all cases. Where fissures are not inflammatory, routine prescription of oral antibiotics is not always necessary. Regular bacteriological monitoring at several different fissure sites allows selection of appropriate antibiotic therapy. The main therapeutic goal in CBS is to treat painful fissures and superinfection.

Neonatal skin barrier: structure, function, and disorders

The development of the human skin from intrauterine to extrauterine life is a balletic interplay of maturing layers and interlocking structures. We discuss this transition and then branch out to touch on issues of premature infant as well as neonatal skin care. Disruption of the barrier function due to toxins and development errors are expounded upon. Staph scalded skin syndrome, collodion membrane, bullous congenital ichthyosiform erythroderma, autosomal recessive ichthyosis (lamellar and congenital ichthyosiform erythroderma), and harlequin fetus are used as examples of these disruptions. Discussion of therapy with the authors' experience highlights each disease.

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.