False-negative prenatal diagnosis of restrictive dermopathy

Restrictive dermopathy is a rare autosomal recessive lethal skin dysplasia. It has been assumed that the characteristic morphologic abnormalities should allow a reliable prenatal diagnosis on fetal skin biopsies at about 20 weeks pregnancy. We report on a false-negative prenatal diagnosis. © 1992 Wiley-Liss, Inc.     

Rapid processing of fetal skin for prenatal diagnosis by light and electron microscopy.

A method has been developed for rapid processing of fetal skin for prenatal diagnosis of hereditary skin diseases by light and electron microscopy. Fixation, dehydration, embedding, and polymerisation can be achieved in about 5 h. The quality of tissue preservation compares favourably with that produced by slower conventional techniques. This procedure may provoke a wider interest in the potential use of fetal skin biopsy in prenatal diagnosis, especially if identification of structural abnormalities is a feasible alternative to more time consuming biochemical analysis.     

Prenatal diagnosis of bullous ichthyosiform erythroderma: detection of tonofilament clumps in fetal epidermal and amniotic fluid cells.

The prenatal diagnosis of bullous ichthyosiform erythroderma (BIE) has been achieved at 20 weeks' gestation by electron microscopic identification of a pathognomonic cytoskeletal abnormality within fetal epidermal cells obtained by fetoscopic skin biopsy. The same abnormality was also observed in skin derived amniotic fluid cells. The question whether amniocentesis might be used instead of fetoscopy for future prenatal detection of BIE is discussed.     

Prenatal diagnosis and fetal pathology of aspartylglucosaminuria

The prenatal diagnosis of aspartylglucosaminuria (AGU), a lysosomal storage disorder of glycoprotein degradation, was made by demonstrating the deficiency of N-aspartylglucosaminidase on cultured cells from a midterm amniotic fluid sample. Four other amniotic fluid studies from at-risk pregnancies gave a normal or a heterozygote level of enzyme activity. These pregnancies have gone to term and the delivery of healthy babies. The pregnancy with the affected fetus was terminated and the prenatal diagnosis was verified by enzyme assays on cord blood lymphocytes, cultured cells from skin biopsy, and from placental villi. Electron microscopic evidence of lysosomal storage was seen in several organs of the fetus with the notable exception of the central nervous system. The undifferentiated mesenchymal fibroblasts particularly were heavily loaded with cytoplasmic inclusions in skin, liver, kidney, and placenta.     

Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia by linkage analysis

Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia was previously performed by the direct histological analysis of fetal skin obtained by late second trimester fetoscopy. The recent gene mapping of the locus for the disorder to the region of Xq11-21.1 now permits the indirect prenatal diagnosis of the disorder by the method of linkage analysis, based on closely linked marker loci, during the first trimester of pregnancy. We report the prenatal diagnosis of a male fetus with a high probability of the disorder by a linkage analysis utilizing restriction fragment length polymorphisms at the DXS159, PGK1, and DXS72 loci, from a DNA sample obtained by a chorionic villus biopsy at 9 weeks gestation. After further counseling, the pregnancy was terminated but the diagnosis could not be confirmed by histological analysis, even though analysis of skin samples by light and electron microscopy showed lack of hair germs, primary dermal ridges, and sweat gland primordia, due to the early developmental stage of the fetus. The use of DNA-based linkage analysis now offers the opportunity for an earlier diagnosis of X-linked hypohidrotic ectodermal dysplasia by a method other than fetal skin sampling. However, families must also fully understand the present limitations of the method prior to undertaking the procedure.     

Maternal age and recommendation of amniocentesis

We report on the prenatal diagnosis of epidermolysis bullosa letalis with pyloric atresia in a pregnancy not known to be at risk for this condition. Elevated maternal serum alphafetoprotien levels led to ultrasonography which demonstrated gastric dilatation, consistent with pyloric atresia, and echogenic particles in the amniotic fluid, the “snowflake sign,” previously described in two pregnancies of fetuses with disorders of skin sloughing. Amniotic fluid alpha-fetoprotien was markedly elevated and the acetylcholinesterase was positive. The diagnosis of epidermolysis bullosa letalis with pyloric atresia was confirmed after delivery by electron microscopy of fetal skin which showed typical changes of hypoplastic absent hemidesmosomes and separation along the dermal-epidermal junction. None of these abnormal prenatal findings are consistently present in pregnancies with epidermolysis bullosa with pyloric atresia. Thus, although useful when abnormal, when the test results are normal, the need for confirmatory fetoscopy and fetal skin biopsy remains. © 1993 Wiley-Liss, Inc.     

Prenatal diagnosis of Fanconi anemia

Prenatal diagnosis was performed on a fetus at risk for Fanconi anemia. A high spontaneous (0.30 breaks/cell) and diepoxybutane-induced (0.69 breaks/cell) chromosome breakage rate indicated an affected fetus and the pregnancy was terminated. The anatomic findings in the aborted fetus together with cytogenetic findings in cultured fetal skin fibroblasts confirmed the prenatal diagnosis.     

Prenatal diagnosis of neuronal ceroid-lipofuscinoses

We report on the successful prenatal diagnosis of the late infantile "Jansky-Bielschowsky" variant of the neuronal ceroid-lipofuscinoses (NCL). The fetus was studied at 16 weeks of gestation because of an affected sib. Uncultured amniotic fluid cells were studied by conventional electron microscopic techniques. About one-third of a subpopulation of dark, elongated cells contained one or more deposits of curvilinear cytosomes bound by a single unit membrane. These findings were considered typical of the late infantile variant of NCL. After delivery at term, a skin punch biopsy and a buffy coat preparation from the baby were examined and found to have similar characteristic inclusions, which confirmed our prenatal diagnosis.     

产前诊断先天性多发性关节挛缩症的探索

先天性多发性关节挛缩症(arthrogryposis multiplex congenita,AMC)是一种少见的先天性疾病,产前诊断先天性多发性关节挛缩症更是罕见,国内仅有极少数例报道。我们最近报道2例,除2个或以上关节屈曲,挛缩外,其中1例的一些体征,如小下颌,颈蹼,颈部皮肤增厚,积水(水肿),上下肢蹼状畸形等国内未见报道;结合国外学者产前诊断的相关文献报道,提出先天性多发性关节挛缩症的超声产前诊断和鉴别要点,超声产前诊断先天性多发性关节挛缩症进行有价值的探索。     

Prenatal and postnatal diagnosis of diseases of copper metabolism

Menkes' kinky hair disease can be successfully diagnosed both prenatally and postnatally using cultured skin fibroblasts derived from the patient or amniotic fluid cells from the affected fetus. Determination of intracellular copper concentration under normal and copper loaded conditions, as well as examination of the kinetics of copper retention may be necessary for diagnosis. At present, cell culture techniques have been proven to be applicable for postnatal diagnosis of Wilson's disease. More investigation is necessary to determine whether or not the present method for prenatal diagnosis of this disease is possible.     

Trisomy 20 mosaicism in two unrelated girls with skin hypopigmentation and normal intellectual development

The prenatal diagnosis of trisomy 20 mosaicism presents a challenge for practitioners and parents. The diagnosis implies an uncertain risk for an inconsistent set of physical and developmental findings, as well as a substantial chance for a child that is normal physically and developmentally. We report two girls (ages nine years one month and eight years one month) with normal intelligence and hypopigmented skin areas. Both girls were born after a prenatal diagnosis of trisomy 20 mosaicism in amniocytes. Case 1 had 83% and 57% trisomy 20 cells from two separate amniocenteses and Case 2 had 90% trisomy 20 cells from an amniocentesis. Trisomy 20 was confirmed after birth in urinary sediment (25%) and chorionic villus cells (15%) in Case 1, while cord blood lymphocytes (30 cells) and skin fibroblasts (50 cells) had only 46,XX cells. Trisomy 20 was confirmed after birth in urinary sediment (100%), placenta (100%), cord (10%), amniotic membrane (50%), and skin fibroblasts (30%) in Case 2, while cord blood lymphocytes (100 cells) had only 46,XX cells. This is the first report of a hypopigmented pigmentary dysplasia associated with isolated trisomy 20 mosaicism. Our patients are the oldest reported children with trisomy 20 mosaicism confirmed after birth.     

Trisomy 7 mosaicism prenatally misdiagnosed and maternal uniparental disomy in a child with pigmentary mosaicism and Russell- Silver syndrome

Prenatal diagnosis of true mosaic trisomy 7 is rare in amniotic fluid and can be misinterpreted as pseudomosaic. The phenotype is highly variable and may be modified by a maternal uniparental disomy of chromosome 7 leading to mild Russell-Silver syndrome (RSS). We report here the third postnatal case of mosaic trisomy 7 with maternal uniparental disomy of chromosome 7 in a boy presenting a mild RSS. Fetal karyotype performed in amniocentesis for intrauterine growth retardation was considered normal. Mosaic trisomy 7 was diagnosed after birth, on fibroblasts karyotype performed for blaschkolinear pigmentary skin anomalies and failure to thrive. Maternal uniparental disomy of chromosome 7 was observed in blood sample. Retrospectively, trisomic 7 cells were identified in one prenatal long-term flask culture revealing a prenatal diagnosis failure. This report emphasizes the difficulty of assessing fetal mosaicism and distinguishing it from pseudomosaicism in cultured amniocytes. It is important to search for uniparental disomy as an indirect clue of trisomy 7 mosaicism and a major prognosis element. Although there are only few prenatal informative cases, detection of trisomy 7 in amniocentesis appears to be associated with a relatively good outcome when maternal uniparental disomy has been ruled out.     

Two cases of tetrasomy 9p syndrome with tissue limited mosaicism

Tetrasomy of short arm of chromosome 9 constitutes a clinically recognizable chromosomal syndrome. Isochromosome 9p shows a strong propensity to tissue-limited mosaicism. It occurs predominantly in peripheral blood cultures, often at a lower frequency or even absent in skin, amniotic fluid or chorionic villous cell cultures. Tissue-limited nature of mosaicism may render prenatal detection of this condition very difficult. Herein, we report two new cases of mosaic tetrasomy 9p. Conventional cytogenetics (CC) and FISH studies demonstrated a differential expression of the mosaicism in several tissues. We review the literature and discuss the implications of these findings in cytogenetic prenatal diagnosis.     

Prenatal diagnosis of harlequin ichthyosis

We report the successful prenatal diagnosis of ichthyosis in the fetus of a woman whose previous liveborn child was affected with "harlequin ichthyosis". The fetal diagnosis was established through analysis of ultrasonographically guided fetoscopic skin biopsies. These biopsies showed premature hyperkeratosis, most marked around hair follicles and sweat ducts, and forming plugs of hyperkeratotic debris. These observations were in distinct contrast to those in control fetuses, whose epidermis consists of squamous epithelium only a few cells in depth with minimal keratinization.     

Use of type VII collagen gene (COL7A1) markers in prenatal diagnosis of recessive dystrophic epidermolysis bullosa.

Generalised recessive dystrophic epidermolysis bullosa (EB) is a severe inherited disease in which patients suffer from blistering and scarring of the skin and mucous membranes after minor mechanical trauma. Tight genetic linkage has been established to the type VII collagen gene (COL7A1) at 3p21, with no evidence of locus heterogeneity. Several COL7A1 mutations have now been identified in recessive dystrophic EB patients. Prenatal diagnosis has been performed by examination of a fetal skin biopsy taken at about 16 weeks' gestation, and relies on identification of characteristic ultrastructural and immunohistochemical changes. We have now achieved a first trimester prenatal diagnosis using intragenic and flanking COL7A1 markers in a pregnancy at risk for recessive dystrophic EB. Segregation of the informative markers predicted the baby would be an unaffected carrier. The pregnancy continued to term and a healthy baby was born, confirming this result.     

白化病的临床实践指南

白化病是一组以眼、皮肤和毛发色素减退以及相关损害为主要特征的孟德尔遗传病,呈常染色体隐性或X连锁隐性遗传。目前已鉴定出18个致病基因,其突变谱具有人群特异性。白化病的分子分型是基因诊断和产前诊断的基础,也是精准诊疗的先决条件。本文结合中国人群白化病的特点,为其制定了临床实践指南。     

Prenatal diagnosis of Maroteaux-Lamy syndrome

Maroteaux-Lamy syndrome exhibits deficient activity of the enzyme arylsulfatase-B in cultured skin fibroblasts. Prenatal diagnosis was successfully attempted in two pregnancies of a consanguineous Chaldean couple whose first child is affected with Maroteaux-Lamy syndrome. In both instances, deficient arylsulfatase-B activity was observed in amniotic fluid cell cultures, and the diagnosis was confirmed by 35S-sulfate studies and postmortem enzymology and electron microscopy. The prenatal diagnosis of Maroteaux-Lamy syndrome remains problematic. Residual activity of arylsulfatase-B in the affected homozygote can make interpretation difficult, and the behavior of many lysosomal enzymes varies greatly in response to tissue culture conditions and enzyme extraction processes.     

Use of microtechniques for the detection of lysosomal enzyme disorders: Tay-Sachs disease, Gm1-gangliosidosis and Fabry disease

A preliminary report on the use of microtechniques for the detection of three lysosomal storage diseases (Tay-Sachs, GM1-gangliosidosis and Fabry disease) is presented. This microassay method uses from 100 to 300 cultured amniotic fluid cells or skin fibroblasts. A comparison between values for total activity and heat inactivated forms of hexosaminidase (in Tay-Sachs disease) is presented. The feasibility of the use of this microtechnique in prenatal diagnosis is discussed.     

27 years of prenatal diagnosis for Huntington disease in the United Kingdom

PurposeThere is little long-term, population-based data on uptake of prenatal diagnosis for Huntington disease (HD), a late-onset autosomal dominant neurodegenerative disorder, and the effect of the availability of preimplantation genetic diagnosis (PGD) on families’ decisions about conventional prenatal diagnosis is not known. We report trends in prenatal diagnosis and preimplantation diagnosis for HD in the United Kingdom since services commenced.MethodsLong-term UK-wide prospective case record-based service evaluation in 23 UK Regional Genetic Centres 1988–2015, and four UK PGD centers 2002–2015.ResultsFrom 1988 to 2015, 479 prenatal diagnoses were performed in the UK for HD. An exclusion approach was used in 150 (31%). The annual rate of HD prenatal diagnosis has remained around 18 (3.5/million) over 27 years, despite a steady increase in the use of PGD for HD since 2002.ConclusionAlthough increasing number of couples are choosing either direct or exclusion PGD to prevent HD in their offspring, both direct and exclusion prenatal diagnosis remain important options in a health system where both PGD and prenatal diagnosis are state funded. At-risk couples should be informed of all options available to them, preferably prepregnancy.     

Analysis of cultured chorionic villi in a case of osteogenesis imperfecta type II: implications for prenatal diagnosis

We examined collagens produced by cultured cells from skin, chorionic villi, and placental membranes of a 32 week fetus with osteogenesis imperfecta (OI) type II. We observed that skin fibroblasts synthesized two populations of pro alpha 1(I) chains of type I procollagen; one population was normal, while the other population had excessive post-translational modification. The thermal stability of helices containing the overmodified chains was reduced 1-2 degrees C. Most significantly, the cells cultured from chorionic villi produced type I collagen chains with the same electrophoretic abnormalities as the skin collagen. This suggests that chorionic villus sampling (CVS) is a means of prenatal diagnosis for families with a previous type II or type IV OI infant.