A prospective study of brachytelephalangic chondrodysplasia punctata: identification of arylsulfatase E mutations, functional analysis of novel missense alleles, and determination of potential phenocopies.

PURPOSE: The only known genetic cause of brachytelephalangic chondrodysplasia punctata is X-linked chondrodysplasia punctata 1 (CDPX1), which results from a deficiency of arylsulfatase E (ARSE). Historically, ARSE mutations have been identified in only 50% of male patients, and it was proposed that the remainder might represent phenocopies due to maternal-fetal vitamin K deficiency and maternal autoimmune diseases. METHODS: To further evaluate causes of brachytelephalangic chondrodysplasia punctata, we established a Collaboration Education and Test Translation program for CDPX1 from 2008 to 2010. Of the 29 male probands identified, 17 had ARSE mutations that included 10 novel missense alleles and one single-codon deletion. To determine pathogenicity of these and additional missense alleles, we transiently expressed them in COS cells and measured arylsulfatase E activity using the artificial substrate, 4-methylumbelliferyl sulfate. In addition, clinical data were collected to investigate maternal effects and genotype-phenotype correlations. RESULTS: In this study, 58% of males had ARSE mutations. All mutant alleles had negligible arylsulfatase E activity. There were no obvious genotype-phenotype correlations. Maternal etiologies were not reported in most patients. CONCLUSION: CDPX1 is caused by loss of arylsulfatase E activity. Around 40% of male patients with brachytelephalangic chondrodysplasia punctata do not have detectable ARSE mutations or known maternal etiological factors. Improved understanding of arylsulfatase E function is predicted to illuminate other etiologies for brachytelephalangic chondrodysplasia punctata.

Maternal vitamin K deficient embryopathy: association with hyperemesis gravidarum and Crohn disease.

Chondrodysplasia punctata (CDP) is an etiologically heterogeneous disorder characterized by the radiographic finding of stippled epiphyses (punctate calcifications). It is often accompanied by a characteristic facial appearance, known as the Binder phenotype, which is attributed to hypoplasia of the nasal cartilages; abnormal distal phalanges (brachytelephalangy) are a common component manifestation as well. We report eight patients with a Binder phenotype with or without CDP who all shared a known or suspected maternal deficiency of vitamin K. We suspect that this phenotype is probably under recognized, and we hope to increase awareness about the maternal risk factors, especially hyperemesis gravidarum, which lead to nutritional deficiency.

Phenocopy of warfarin syndrome in an infant born to a mother with sickle cell anemia and severe transfusional iron overload.

Neonatal chondrodysplasia punctata (CDP) is characterized by epiphyseal stippling and midfacial hypoplasia. CDP is usually inherited, but can be acquired because of maternal vitamin K deficiency. We describe an infant with CDP born to a teenager with sickle cell anemia and transfusional iron overload. The mother had severe liver fibrosis, elevated liver iron concentration (34 mg Fe/g), and coagulopathy, but no gestational use of warfarin. Fetal abnormalities were attributed to vitamin K deficiency secondary to liver dysfunction from iron toxicity. Treatment of iron overload among women with sickle cell anemia of childbearing potential is important to avoid possible CDP in newborns.

Malformation syndromes caused by disorders of cholesterol synthesis.

Cholesterol homeostasis is critical for normal growth and development. In addition to being a major membrane lipid, cholesterol has multiple biological functions. These roles include being a precursor molecule for the synthesis of steroid hormones, neuroactive steroids, oxysterols, and bile acids. Cholesterol is also essential for the proper maturation and signaling of hedgehog proteins, and thus cholesterol is critical for embryonic development. After birth, most tissues can obtain cholesterol from either endogenous synthesis or exogenous dietary sources, but prior to birth, the human fetal tissues are dependent on endogenous synthesis. Due to the blood-brain barrier, brain tissue cannot utilize dietary or peripherally produced cholesterol. Generally, inborn errors of cholesterol synthesis lead to both a deficiency of cholesterol and increased levels of potentially bioactive or toxic precursor sterols. Over the past couple of decades, a number of human malformation syndromes have been shown to be due to inborn errors of cholesterol synthesis. Herein, we will review clinical and basic science aspects of Smith-Lemli-Opitz syndrome, desmosterolosis, lathosterolosis, HEM dysplasia, X-linked dominant chondrodysplasia punctata, Congenital Hemidysplasia with Ichthyosiform erythroderma and Limb Defects Syndrome, sterol-C-4 methyloxidase-like deficiency, and Antley-Bixler syndrome.

Non-cardiac manifestations of neonatal lupus erythematosus.

Neonatal lupus erythematosus (NLE) is characterized by the transplacental passage of maternal anti-Ro and/or anti-La antibodies and characteristic illnesses in the foetus/neonate. Most attention has focused on the most serious complication- cardiac involvement. This article will focus on non-cardiac involvement. Skin involvement (cutaneous NLE) is present in 15-25% of children with NLE. The rash of NLE tends to be photosensitive but may be present at birth or in non-sun exposed areas. It is most frequently seen around the eyes, not in the malar area, but also occurs in other parts of the body. The pathology resembles the rash of subacute cutaneous lupus erythematosus. Anti-Ro antibodies are present in >95% with the remaining mothers having anti-U1RNP antibodies only. Asymptomatic elevation of liver function tests, which may be associated with evidence of cholestasis, is seen in 10-25% of cases of NLE. Mild hepatomegaly and less commonly splenomegaly may be present. Liver involvement seen in isolation or associated with other features. The pathology resembles idiopathic neonatal giant cell hepatitis. Any haematological lineage, neutropenia and thrombocytopenia most commonly, may be affected by NLE. Haematological involvement is almost always asymptomatic. There are protean manifestations of neurologic involvement in NLE: hydrocephalus, non-specific white matter changes, calcification of the basal ganglia and a 'vasculopathy'. The most unusual feature of NLE is the radiographic finding of stippling of the epiphyses (chondrodysplasia punctata). Overall, non-cardiac involvement of NLE is more common than cardiac. The study of these manifestations may lead to new insight into how autoantibodies lead to disease.

Lethal epiphyseal stippling in the foetus and neonate; pathological implications.

Autopsy reports accumulated since 1991 contained 30 cases in which routine radiological investigation had demonstrated radio-dense stippling of the epiphyses. The case histories, pregnancy progress, clinical manifestations, cytogenetic investigations, and autopsy findings have been tabulated and analysed for the purpose of diagnostic discrimination. Firm diagnoses were obtained in eight instances: warfarin embryopathy-three, trisomy 18-three, lethal multiple pterygium syndrome-one. Other possible but unconfirmed diagnoses were chromosomal aneuploidy-three, sonic hedgehog phenotype-one, CHARGE association-one, intrauterine infection-one. The value of autopsy in foetuses and neonates with lethal epiphyseal stippling syndromes is exemplified by the detection of multiple visceral abnormalities in ten instances.

Chondrodysplasia punctata associated with maternal autoimmune diseases: expanding the spectrum from systemic lupus erythematosus (SLE) to mixed connective tissue disease (MCTD) and scleroderma report of eight cases.

Chondrodysplasia punctata (CDP) is etiologically a heterogeneous condition and has been associated with single gene disorders, chromosome abnormalities and teratogenic exposures. The first publication of the association between CDP and maternal autoimmune connective tissue disorder was by Curry et al. 1993]. Chondrodysplasia punctata associated with maternal collagen vascular disease. A new etiology? Presented at the David W. Smith Workshop on Morphogenesis and Malformations, Mont Tremblant, Quebec, August 1993] and subsequently, other cases have been reported. We report on eight cases of maternal collagen vascular disease associated with fetal CDP and included the cases reported by Curry et al. 1993. Chondrodysplasia punctata associated with maternal collagen vascular disease. A new etiology? Presented at the David W. Smith Workshop on Morphogenesis and Malformations, Mont Tremblant, Quebec, August 1993] and Costa et al. [1993]. Maternal systemic lupus erythematosis (SLE) and chondrodysplasia punctata in two infants. Coincidence or association? 1st Meeting of Bone Dysplasia Society, Chicago, June 1993] which were reported in an abstract form. We suggest that maternal autoimmune diseases should be part of the differential diagnosis and investigation in newborns/fetuses with CDP. Thus, in addition to cardiac evaluation, fetuses/newborn to mothers with autoimmune diseases should have fetal ultrasound/newborn examination and if indicated, X-rays, looking for absent/hypoplastic nasal bone, brachydactyly, shortened long bones and epiphyseal stippling.

Genetic ablation of Rac1 in cartilage results in chondrodysplasia.

Small GTPases of the Rho family have been implicated in the regulation of many intracellular processes. However, their tissue-specific roles in mammalian growth and development in vivo remain largely unknown. Here we describe the effects of cartilage-specific inactivation of the Rac1 gene in mice. Mice carrying this mutation show increased lethality, skeletal deformities, severe kyphosis and dwarfism. Rac1-deficient growth plates are disorganized and hypocellular, with chondrocytes of abnormal shape and size. Rac1-deficient chondrocytes also display reduced adhesion and spreading on collagen II and fibronectin as well as altered organization of the actin cytoskeleton, suggesting that Rac1 is required for normal cell-extracellular matrix interactions in cartilage. This phenotype is accompanied by reduced proliferation, increased apoptosis and deregulated expression of the cell cycle genes cyclin D1 and p57 in vivo. Moreover, phosphorylation of p38 MAP kinases is greatly reduced and expression of a key regulator of cartilage development, Indian hedgehog, is increased in mutant mice. In summary, these data identify a novel, essential and tissue-specific role of Rac1 in skeletal development and demonstrate that Rac1 deficiency affects numerous regulatory pathways in cartilage.

Chondrodysplasia punctata in siblings and maternal lupus erythematosus.

Chondrodysplasia punctata (CDP) was diagnosed clinically and radiographically in a male child born in Cape Town in 1991. His only sibling, a brother born in 2000 was similarly but more severely affected. The boys' mother had longstanding disseminated lupus erythematosus and epilepsy, for which she had been treated with chloraquine and other therapeutic agents during both pregnancies. The parents were non-consanguineous, and the family history was unremarkable. In addition to these affected brothers, seven previous instances of the association of CDP and maternal lupus erythematosus (MLE) have been reported. On this basis, MLE must be regarded as yet another causative factor in CDP.

Chondrodysplasia punctata (CDP) with features of the tibia-metacarpal type and maternal phenytoin treatment during pregnancy.

We describe a 2-year-old boy with chondrodysplasia punctata (CDP). The boy was exposed to phenytoin, in combination with carbamazepine, during pregnancy. There has been previous evidence for a connection between phenytoin exposure during pregnancy and chondrodysplasia punctata. The boy had clinical and some radiological characteristic features of CDP, of the tibia-metacarpal type. We know of no other report on a child exposed to phenytoin during pregnancy who developed CDP of this type.

Disorders of post-squalene cholesterol biosynthesis leading to human dysmorphogenesis.

Insights in molecular developmental biology in animals and humans are facilitating the understanding of pathophysiologic mechanisms in dysmorphogenesis or abnormalities in normal embryologic structural development. A milestone was recognition of the role of shh in morphogenesis of craniofacial structures, especially the development of holoprosencephaly. The dependence of hedgehog morphogens on cholesterol modification for normal hedgehog signaling function has particular relevance to disorders of cholesterol synthesis which manifest dysmorphogenesis. Four human disorders of morphogenesis (Smith-Lemli-Opitz syndrome, desmosterolosis, X-linked chondrodysplasia punctata, CHILD syndrome) have recently been shown to be caused by sterol abnormalities resulting from cholesterol biosynthesis enzyme deficiencies. This review summarizes the clinical, biochemical and molecular data in these disorders with an emphasis on understanding the pathophysiology of dysmorphogenesis.

X-Linked dominant disorders of cholesterol biosynthesis in man and mouse.

The X-linked dominant male-lethal mouse mutations tattered and bare patches are homologous to human X-linked dominant chondrodysplasia punctata and CHILD syndrome, rare human skeletal dysplasias. These disorders also affect the skin and can cause cataracts and microphthalmia in surviving, affected heterozygous females. They have recently been shown to result from mutations in genes encoding enzymes involved in sequential steps in the conversion of lanosterol to cholesterol. This review will summarize clinical features of the disorders and describe recent biochemical and molecular investigations that have resulted in the elucidation of the involved genes and their metabolic pathway. Finally, speculations about possible mechanisms of pathogenesis will be provided.

Chondrodysplasia punctata stemming from maternal lupus erythematosus.

The finding of stippled epiphyses on a neonatal radiograph generates a wide differential diagnosis, including genetic and teratogenic causes. We report the case of a male infant with stippled epiphyses evident on neonatal radiographs in whom a typical rash of lupus erythematosus developed. The skin abnormalities in the infant resulted in a diagnosis of systemic lupus erythematosus in his mother. Over a 3-year follow-up period, the child has demonstrated strikingly short stature, midface hypoplasia, anomalous digital development, slow resolution of the stippled epiphyses, and near normal cognitive development. The differential diagnosis of chondrodysplasia punctata and the literature supporting maternal lupus as one cause are reviewed.

Maternal systemic lupus erythematosus and chondrodysplasia punctata in two sibs: phenocopy or coincidence?

Two sibs with chondrodysplasia punctata in whom the mother was suffering from systemic lupus erythematosus are presented and the radiological features described. Comparison with other forms of chondrodysplasia punctata with a review of the relevant publications is presented and the possible association with maternal systemic lupus erythematosus is highlighted.