Diagnosis and prenatal diagnosis of epidermolysis bullosa herpetiformis (Dowling-Meara) in a mother,two affected children,and an affected fetus

In utero skin biopsy was performed on a fetus at risk of an uncertain form of epidermolysis bullosa (EB). The mother had produced two affected offspring diagnosed variously as having junctional or dystrophic EB. The two offspring and the fetus were products of different fathers. The mother claimed to have no disease and on clinical examination was without blisters. Examination of the fetal skin biopsy by light and electron microscopy revealed separation of the epidermal sheet from the majority of the biopsy sample, although occasional remnants of basal cells remained associated with the basement membrane. Aggregations of keratin filaments were observed within basal cells of the detached epidermis and in the attached basal cell remnants. The diagnosis was thus suggested to be epidermolysis bullosa Dowling-Meara. Re-review of the clinical and laboratory data from the affected infants revealed a clinical and histological pattern consistent with this diagnosis. Further discussion with the mother revealed that her skin had blistered as a child and that she presently had hyperkeratotic palms and soles. This history is consistent with the autosomal dominantly inherited epidermolysis bullosa herpetiformis (Dowling-Meara). This is the first reported prenatal diagnosis of EB Dowling—Meara. The morphological criteria of intraepidermal blistering and clumped keratin filaments within basal and immediately suprabasal cells characteristic of an affected individual postnatally also identified an affected fetus. There is, however, insufficient experience to be certain that these findings will hold from region to region in the body or among all affected fetuses, and thus prenatal diagnosis on a morphological basis should still be made with caution.     

Prenatal diagnosis of congenital non-bullous ichthyosiform erythroderma (lamellar ichthyosis)

We report the first positive prenatal diagnosis ofcongenital non-bullous ichthyosiform erythroderma or lamellar ichthyosis. Fetal skin samples were obtained by fetoscopy at 21 weeks' gestation and examined by light and electron microscopy. Light microscopy revealed a thickened interfollicular epidermis with multiple layers of flattened cells and excessive keratinization of the epidermal lining of the follicular infundibulum. Electron microscopy of the thickened epidermis revealed granular cells that contained larger-than-normal keratohyalin granules and multiple layers of parakeratotic cornified cells. Although there was regional variation in the degree of interfollicular keratinization, follicles from all regions showed greater and more complete keratinization, indicating that they express the abnormality early enough in development to permit prenatal diagnosis at about 20 weeks' gestation.     

Prenatal diagnosis of tyrosinase-negative oculocutaneous albinism by an electron microscopic dopa reaction test of fetal skin

An electron microscopic DOPA reaction test of fetal skin was used for the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism (OCA). The subject was a 34-year-old Japanese woman in her second pregnancy. Her first child, born in 1982, had been previously examined and confirmed to have tyrosinase-negative OCA. The parents requested a prenatal diagnosis and we sampled skin from the upper trunk of the fetus. On conventional electron microscopy, the development of melanosomes in interfollicular melanocytes had progressed no further than stage II. Fetal skin samples incubated with L-DOPA solution indicated a lack of tyrosinase activity and showed that the melanosomes had not progressed beyond stage II. In skin samples from the trunks of three Japanese fetuses aborted for other reasons at 19–20 weeks of gestation, most premature melanosomes were further melanized to stage IV after incubation with L-DOPA solution. A prenatal diagnosis of tyrosinase-negative OCA was made. The parents requested a termination and skin biopsies of the abortus confirmed the diagnosis. This study shows that tyrosinase is normally present in melanocytes of the fetal epidermis at 20 weeks' gestation, and that the electron microscopic DOPA reaction test of a fetal skin biopsy specimen is safe and practical, and provides reliable information for making a prenatal diagnosis of tyrosinase-negative OCA in the second trimester.     

Prenatal diagnosis of harlequin ichthyosis by fetal skin biopsy; Report of two cases

Two cases of harlequin ichthyosis were successfully diagnosed prenatally by fetal skin biopsy. The aborted fetuses were later confirmed to be afflicted with this very unusual skin disease. Both families had a previous history of harlequin ichthyosis. In performing the biopsy, it was found that amniotic fluid cytology can also be very helpful in the diagnosis of this kind of severe ichthyosis. With regard to these families, the disease may have been transmitted in an autosomal dominant fashion, and not in a recessive manner as is commonly believed.     

Prenatal diagnosis of a lethal form of Netherton syndrome by SPINK5 mutation analysis

Netherton syndrome (NS) is a severe autosomal recessive ichthyosis with no specific treatment or prenatal diagnosis available at present. The recent identification of SPINK5, which encodes a serine protease inhibitor, as the defective gene enables DNA-based prenatal diagnosis to be carried out. Here we report the first direct molecular prenatal diagnosis of a lethal form due to a recurrent SPINK5 mutation in three consanguineous Turkish families. XmnI restriction enzyme digestion and DNA sequencing demonstrated that each deceased affected child was homozygous for mutation 153delT inherited from each parent. Analysis of fetal DNA from amniotic fluid cells in Family 1 and from a chorionic villus sampling in Family 3 showed that the fetus was heterozygous for 153delT in both cases. The pregnancies were carried to term and the newborns were unaffected. In Family 2, fetal DNA analysis from chorionic villus biopsy showed in a first pregnancy that the fetus was homozygous for 153delT. The pregnancy was terminated at 13 weeks and DNA analysis of fetal keratinocytes confirmed the prenatal prediction. In a second pregnancy in Family 2, fetal DNA analysis showed heterozygosity for 153delT, and the pregnancy was continued. Direct SPINK5 mutation analysis in families at risk for NS represents the first early, rapid and reliable method for prenatal diagnosis of this life-threatening form of ichthyosis. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal diagnosis of anhidrotic ectodermal dysplasia

This paper reports on successful prenatal diagnosis of X-linked anhidrotic ectodermal dysplasia (AED) by means of light and electron microscopy on fetal skin biopsies obtained under fetoscopy. In the present family two brothers of the proband were severely affected with the full symptomatology of AED, the pregnant female and her mother revealed minor symptoms with patches of skin lacking vellus hair. Control of lesional skin of the affected family members by electron microscopy revealed no ultrastructural abnormalities. However, all biopsies lacked skin appendages including hair follicles, sebaceous glands, and sweat glands. The lack of pilosebaceous follicles can be used as a diagnostic criterion since these structures are fully developed in normal fetuses of 20 weeks whereas the development of sweat glands does not start before week 20 to 24 of fetal life. Skin biopsies were taken from various regions of the fetus at risk via fetoscopy in week 20 and processed for light and electron microscopy. All samples revealed complete absence of all skin appendages in contrast to a total of 61 non-AED fetuses. Thus positive prenatal diagnosis of AED was made and the pregnancy was terminated. Control investigations after abortion confirmed the diagnosis.     

Probable exclusion of juvenile neuronal ceroid lipofuscinosis in a fetus at risk: An interim report

In a family with two children affected by juvenile neuronal ceroid lipofuscinosis (JNCL) an attempt was made at the prenatal diagnosis of the disorder. The following tissues from the fetus at risk were investigated by electron microscopy and were found to be free of fingerprint profiles and curvilinear bodies, typical for JNCL: uncultivated amniotic fluid cells, lymphocytes isolated from fetal blood, and fetal skin biopsy specimens. The child was born at the 34th week of gestation and was clinically normal at the age of 15 months. Postnatally, lymphocytes (isolated at the age of 6 and 15 months) and skin tissue (taken at the age of 15 months) were found to be morphologically normal. It is highly unlikely that the child is affected but definite proof of the absence of JNCL remains difficult at this age.     

Fetal tissue involvement in the late infantile type of neuronal ceroid lipofuscinosis

Prenatal diagnosis in a pregnancy at risk for late infantile neuronal ceroid lipofuscinosis (Batten's disease) was undertaken at 17 weeks' gestation by ultrastructural examination of amniotic fluid cells. The presence of curvilinear profiles indicated an affected fetus and the diagnosis was confirmed, after the pregnancy was terminated, by the finding of many typical curvilinear profiles in multiple tissues which included skin, amnion, umbilical vessels, blood, liver, and brain. Comparison between the involved cells in the amniotic fluid and fetal tissues suggests that these cells are probably derived from the periderm, and possibly also from the amnion. The prominent presence of cytosomes in the periderm and intermediate cells of the fetal epidermis and occasionally also in the endothelial cells of the dermis suggests that fetal skin may be a useful alternative site for assessing fetal involvement. Control specimens of the amniotic fluid, fetal skin, amnion, and liver showed no similar cytosomes. However, some control amniotic fluid samples did contain cells with large collections of irregular trilaminar membranes, and these could be open to misinterpretation. It is important that only typical curvilinear profiles are considered as an indication of an affected pregnancy.     

First-trimester prenatal diagnosis of the nijmegen breakage syndrome and ataxia telangiectasia using an assay of radioresistant dna synthesis

Prenatal diagnosis was performed in two pregnancies at risk of the Nijmegen breakage syndrome. In one pregnancy, an affected fetus was diagnosed by demonstration of radioresistant DNA synthesis, using autoradiographic detection of incorporated tritiated thymidine in cultured chorionic villus cells. The diagnosis was confirmed in fetal skin fibroblasts. In the other case, the fetus appeared unaffected. Using the same procedure, unaffected fetuses were predicted from chorionic villus cells in two pregnancies at risk of ataxia telangiectasia, which is another genetic disorder showing the feature of radioresistant DNA synthesis. The present biochemical method for prenatal detection of Nijmegen breakage syndrome and ataxia telangiectasia can be used as a simplified alternative to the cytogenetic procedures reported earlier for ataxia telangiectasia.     

Abnormal karyotype in the chorion,not confirmed in a subsequently aborted fetus

An abnormal fetal karyotype, containing a del 16(q21-qter) as an extra chromosome, was diagnosed in all 14 metaphases examined in a sample of chorionic villous biopsy material. After elective abortion a mosaicism for this cell-line together with a normal one was detected in the chorionic tissue. Fibroblast cultures from several fetal skin biopsies all revealed a normal karyotype.     

Can oculocutaneous albinism be diagnosed prenatally?

A study of scalp and forearm skin biopsies from normally pigmented fetuses of gestational ages 16 to 28 weeks has indicated that prenatal diagnosis of albinism is a theoretical possibility. Pigment is not present in cells of the epidermis but can be found in hair follicles at the bulbous peg stage in the scalp only. Such hair follicles are present in the scalp as early as 16 weeks gestation. The findings indicate that prenatal diagnosis of albinism could be made on a scalp biopsy within the second trimester of pregnancy.     

First-trimester biochemical and molecular diagnoses using chorionic villi: High accuracy in the U.S. collaborative study

The accuracy of biochemical and molecular prenatal diagnoses using chorionic villi as the fetal source was assessed by seven centres participating in the NICHD collaborative study on the safety and accuracy of chorionic villus sampling (CVS) and amniocentesis. Of 601 pregnancies studied, biochemical methods were used to determine the diagnosis in 283 fetuses at risk for 35 different metabolic disorders. Fifteen different lysosomal storage diseases accounted for 81 per cent of the biochemical prenatal diagnoses performed, with 57 per cent of these pregnancies at risk for Tay-Sachs disease. No errors were made in the biochemical diagnoses that predicted affected or unaffected fetuses. However, the diagnoses of certain disorders (e.g., mucopolysacchariodosis type IH, metachromatic leukodystrophy, and Krabbe disease) occasionally required confirmatory studies in cultured amniocytes because the enzyme results were inconclusive in direct and/or cultured villi or due to the presence of a pseudodeficiency allele. Of these, only the diagnosis of a fetus at risk for Krabbe disease remained inconclusive after special studies to discriminate between mutant and pseudodeficiency alleles. Recombinant DNA techniques were used to predict the diagnosis of 318 fetuses at risk for 16 different disorders in which the defective disease gene could be detected either directly or by linkage analysis to a nearby polymorphic marker. Of these, 32 per cent were for haemoglobinopathies, 25 per cent for cystic fibrosis, 24 per cent for Duchenne or Becker muscular dystrophy, and 7 per cent for haemophilias. Pregnancies at risk for known disorders with specific molecular lesions (e.g., sickle cell disease) were accurately diagnosed in direct and/or cultured villi. Diagnoses requiring analyses with closely linked polymorphic markers were occasionally uninformative or inconclusive. Maternal contamination was not reported in any biochemical or molecular-based diagnosis. These studies document the high accuracy and rapidity of both biochemical and mutation-specific prenatal diagnoses with direct and cultured chorionic villi.     

Prenatal detection of X-linked ichthyosis by maternal serum screening for down syndrome

Maternal serum unconjugated oestriol (uE3) was measured in 15 375 pregnancies during 2 years of second-trimester risk assessment for Down syndrome using biochemical markers. Very low levels of uE3 (<0·1 MOM) were detected in 22 serum samples (0·14 per cent). Very low uE3 was associated with an adverse outcome in 13 pregnancies including fetal death and miscarriage (N=11), anencephaly (N=1), and Meckel—Gruber syndrome (N=1). Dry scales on the skin appeared in the first year of life in four boys. From dermatological diagnosis, prenatal uE3 levels, and pedigree analysis, it is concluded that at least 5 in approximately 7500 male births in the study population are affected by steroid sulphatase deficiency, which is the biochemical defect in X-linked ichthyosis. Very low uE3 levels in the second trimester are indicative of this disease in pregnancies with normal ultrasound findings.     

Adult-onset GM2 gangliosidosis diagnosed in a fetus

Amniocentesis and subsequent tests are reported on a fetus conceived of a rare mating type: its mother has an intermediate level of β hexosaminidase A (HEX A), characteristic of carriers of Tay-Sachs disease (TSD), while the father suffers from an adult-onset GM₂ ganglio-sidosis (AOG) with severe HEX A deficiency. Activity of HEX A in the cultured fetal cells was very low when measured by the heat-inactivation method, thus showing the typical biochemical phenotype of TSD fetuses. However, upon separation of HEX isozymes by ion exchange chromatography, residual HEX A (17 per cent of total HEX) was demonstrated. Also in contrast to TSD fetuses, this fetus' fibroblasts were able to synthesize the precursor of a chains of HEX, and ultrastructural examination of its brain revealed few atypical lamellar bodies, unlike those found in TSD fetuses of the same gestational age. It is therefore concluded that the fetus was not affected with TSD, but rather with AOG.     

Genetic basis of lethal junctional epidermolysis bullosa in an affected fetus: Implications for prenatal diagnosis in one family

Fetal skin biopsy at 20 weeks' gestation in a woman at risk for a child with the lethal skin-blistering disorder junctional epidermolysis bullosa (Herlitz) confirmed an affected fetus. Genomic DNA from the aborted fetus was examined for mutations in laminin 5, a macromolecule involved in adhesion at the dermal-epidermal junction, and a candidate protein in this condition. Polymerase chain reaction (PCR) amplification of exon 10 and parts of the flanking introns of the gene encoding the β3 chain of laminin 5 (LAMB3) and subsequent analysis by agarose gel electrophoresis showed a more slowly migrating band in the affected fetus compared with the normal control. Nucleotide sequencing of the abnormal PCR product revealed a homozygous 77 bp duplication within the exon, resulting in a premature termination codon 250 bp downstream from the 3′ end of the duplication. Maternal DNA was heterozygous for the mutant and wild-type alleles. These findings illustrate the genetic basis of the skin disease in this case and also offer the prospects of a simple, rapid, and reliable first-trimester DNA-based prenatal, or even preimplantation, diagnostic test for future pregnancies in this family.     

Complex mosaicism associated with trisomy 9

Fetal karyotypes can be routinely obtained by chorionic villus biopsy, amniocentesis, or fetal blood sampling. Interpretation of results and subsequent counselling can be complicated by pseudomosaicism or mosaicism confined to the placenta or other tissues. We illustrate this by reporting a case of an abnormal fetus with a total of three karyotypically different cell lines (46,XXrpar; 47,XX, + 9; and 47,XX, + del (9) (q11) in different tissues (placenta, lung, gonad, and skin).     

Mosaicism of isochromosome 18p.

The first case of isochromosome 18p as a mosaic in a male fetus diagnosed by amniocentesis is reported. After termination of the pregnancy at 21 weeks gestation biopsies from different fetal organs as well as from the placenta were taken and set up for long term cell cultures. The distribution of the normal and abnormal cell-line in fetal organs was unequal. Unexpectedly the metaphases in the placenta and the lymphocyte culture all showed a normal karyotype. The tetrasomy 18p is associated with a uniform phenotype, even in fetal life, characterized by a small head with protuberant occiput, low-set ears with posterior rotation, epicanthic fold, sharp pinched nose, convex and poorly formed philtrum, high-arched palate, retrognathia, flexion contractures of fingers, short and broad hallux, hypoplastic penis, angulation of clavicles and mild scoliosis. The propositus showed no growth retardation.     

Further examples of trisomy-20 mosaicism in amniotic cell cultures

Amniotic fluid cultures from two patients showed trisomy-20 mosaicism. No trisomy-20 cells were found in a normal full term infant and in multiple tissue biopsies and fetal blood from a fetus after a termination of pregnancy. No definitive advice is yet possible for parents where trisomy-20 amniotic cell mosaicism is detected. Fetoscopy and fetal blood sampling are of no value and termination of pregnancy is not indicated by empirical evidence. Preferential trophoblastic non-disjunction (Kalousek and Dill, 1983) is discussed as a possible partial explanation for the variable occurrence and distribution of this type of mosaicism.     

Trisomy 12 mosaicism in amniocytes and dysmorphic child despite normal chromosomes in fetal blood sample

Trisomy 12 mosaicism (44 per cent) was detected prenatally in cultured amniocytes. A cordocentesis was performed to confirm the result. Only normal cells were found in the fetal blood sample. The fetus was estimated to be at a low risk of having a chromosomal abnormality and the pregnancy continued. Eight days after birth, a congenital heart defect was detected in the child. Several dysmorphic features were also evident. Further karyotyping of different tissues revealed normal blood and urinary cells but trisomic cells in the placenta (100 per cent) and in skin fibroblasts (25 per cent). The child died at 5 weeks of age. In this case, the fetal blood sample failed to reveal the real chromosome constitution of the fetus.