Prenatal diagnosis of carbamoyl-phosphate synthetase deficiency by fetal liver biopsy

In a pregnancy at risk for carbamoyl-phosphate synthetase (CPS) deficiency, prenatal diagnosis was attempted by fetal liver biopsy, performed at 18 weeks of gestation. CPS activity was absent and the diagnosis was confirmed after termination of the pregnancy. The technique employed for fetal liver biopsy is described together with an evaluation of its possible role in prenatal diagnosis.     

Prenatal diagnosis of glycogen storage disease type 1b using denaturing high performance liquid chromatography

Glycogen storage disease type 1b (GSD1b) is an autosomal recessive inborn error of metabolism caused by deficiency of glucose-6-phosphate translocase (G6PT1). Current laboratory diagnosis for GSD1b is established by a functional enzyme assay of glucose-6-phosphatase in both fresh and detergent-treated liver homogenates. This procedure requires liver biopsy and is impractical for routine prenatal diagnosis owing to the high morbidity of fetal liver biopsy. Recently, the gene for GSD1b has been cloned and the prevalent mutations in different ethnic groups have been determined. In this study, prenatal molecular diagnosis was performed for a Chinese family in which a previous child was born homozygous for the G149E mutation. We detected genomic sequence variants by heteroduplex formation, followed by denaturing high performance liquid chromatography (DHPLC). With this method, post-PCR analysis was shortened to 7 min. In the case we analysed, PCR products amplified from the fetal DNA yielded a single peak in the chromatogram, indicating a homozygous state in the fetus. When wild-type PCR products were mixed with fetal PCR products, two peaks were observed, indicating that the fetus was homozygous for the parental (G149E) mutation. Sequencing results confirmed this diagnosis. As a result, the pregnancy was terminated and the diagnosis was confirmed on DNA analysis of the aborted fetus. We show here that DNA mutation analysis can be used in the prenatal diagnosis of GSD1b and that DHPLC promises to be a robust technique for this and other prenatal molecular diagnoses.     

Fetal muscle biopsy as a diagnostic tool in Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a relentless progressive disorder, leading to severe disability during childhood and death in adolescence or early adulthood. In most families, prenatal diagnosis is readily achieved by molecular detection of DNA deletions using chorionic villi or amniocytes, or by linkage analysis. In some cases, however, molecular methods fail to provide a definitive diagnosis and in such cases in utero fetal muscle biopsy may serve as a diagnostic option. We describe three families in whom fetal muscle biopsy was performed, focusing on the prenatal diagnostic dilemmas, the indications and timing for in utero fetal muscle biopsy, and the difficulties encountered.     

Status of prenatal diagnosis using direct interventions on the fetus

Prenatal diagnosis has developed into a large flourishing multidisciplinary branch of medicine. At present prenatal diagnosis is world-wide possible in the second trimester of pregnancy by analysis of both amniotic fluid obtained by amniocentesis or amniotic cell cultures. Ultrasound plays a central role in prenatal diagnosis, and has revolutionized obstetric practice. Without dealing with all aspects of prenatal diagnosis we have discussed the following invasive procedures, which give the prenatal diagnosis its forward thrust: fetal blood sampling including intravascular transfusion, fetal skin-, liver- and muscle biopsy, chorion biopsy, selective birth in twin pregnancies, and fetal therapy including fetal surgery. In utero surgery is in its earliest stages. Such simple procedures as decompression of the hydronephrotic kidney in obstructive uropathy, of the fetal lungs in pleural effusions caused by chylothorax, or of the hydrocephalic ventricle may be useful, but the possible success rate for such efforts remains still uncertain. The possibilities of first-trimester prenatal diagnosis especially by DNA-technology or direct chromosomal and biochemical analysis has stimulated the development of a multiplicity of methods for taking chorion biopsies. Compared with second trimester amniocentesis, the introduction of prenatal diagnosis by chorionic villi sampling would reduce the psychic trauma for patients waiting on results and allow earlier and safer termination of pregnancy.     

Prenatal diagnosis of harlequin ichthyosis by the examination of keratinized hair canals and amniotic fluid cells at 19 weeks' estimated gestational age

Harlequin ichthyosis (HI) is an extremely severe and usually fatal congenital keratinization disorder whose responsible genes have not yet been identified. For prenatal diagnosis, the fetal skin biopsy is the only available method and has been usually performed at 21 to 22 weeks' estimated gestational age (wEGA). Hair canal keratinization is thought to occur around 15 wEGA prior to the interfollicular keratinization, and characteristic abnormalities of HI are known to be expressed more strongly in the hair canal. Thus, we expected the fetal skin specimen at 19 wEGA to have sufficient information for prenatal diagnosis. Fetal skin biopsy was undertaken from a fetus at risk at 19 wEGA. Electron microscopy demonstrated abnormal vacuoles in keratinized cells and malformation of lamellar granules in the hair canal. Clumps of aberrantly keratinized cells containing lipid droplets were seen in the amniotic fluid. The fetus was diagnosed as affected. The abortus at 21 wEGA demonstrated HI phenotype clinically. The present results indicate that the prenatal diagnosis of HI is possible at 19 wEGA, an earlier stage of gestation than previously reported, by the ultrastructural observation of the hair canal and the amniotic fluid cells, but not the interfollicular epidermis, of fetuses at risk.     

In utero fetal muscle biopsy for the diagnosis of Duchenne muscular dystrophy

Deoxyribonucleic acid techniques can be used to diagnose Duchenne muscular dystrophy prenatally in male fetuses that are at risk. Deoxyribonucleic acid-based prenatal diagnosis can be impossible when there is only one prior affected male and there is no identifiable deletion or alteration. We performed fetal muscle biopsy in utero in such a case and documented the presence of dystrophin, thereby confirming normality in a male fetus at risk. This first in utero experience adds fetal muscle biopsy to the available procedures for fetal tissue diagnosis.     

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.     

In utero fetal muscle biopsy: a precious aid for the prenatal diagnosis of Duchenne muscular dystrophy.

Prenatal diagnosis for Duchenne muscular dystrophy can usually be performed using DNA analysis. This approach would be impossible when there is only one prior affected male and no identifiable gene deletion. Therefore, in utero fetal thigh muscle biopsy with direct examination of muscle by dystrophin analysis may provide the only means of prenatal diagnosis. We report such a case in which fetal muscle biopsy was able to exclude Duchenne muscular dystrophy. A detailed literature review of the topic is provided.     

The prenatal diagnosis of the cerebro-hepato-renal syndrome of Zellweger

The prenatal diagnosis of the cerebro-hepato-renal syndrome of Zellweger (CHRS) was made by assaying the levels of very long chain fatty acids (VLCFAs) in amniotic fluid cell cultures, obtained by amniocentesis at 16 1/2 weeks of pregnancy. The family-at-risk, because they had previously borne a child with CHRS, accepted these results as indications of an affected fetus, and chose to terminate the pregnancy at 20 1/2 weeks of gestation. The diagnosis was confirmed by the phenotype of the aborted fetus and the presence of markedly elevated levels of VLCFAs in fetal liver homogenates. The prenatal diagnosis of CHRS, which can now readily be determined from amniotic fluid cell cultures, is an important step in genetic counselling of families-at-risk for this disease.     

In utero diagnosis of trichothiodystrophy by endoscopically-guided fetal eyebrow biopsy

OBJECTIVE: To describe the prenatal diagnosis of trichothiodystrophy (TTD) through endoscopically-guided fetal eyebrow biopsy. MATERIALS AND METHODS: A 32-year-old patient, gravida 4, para 3, with a history of 2 previous infants affected with TTD was referred at 17(5)/(7) weeks for fetal hair biopsy. DNA repair studies had been normal in the previous children. Four 1-mm biopsies were obtained from the external aspect of the fetal eyebrows under direct endoscopic guidance. Fetal hair samples were assessed with polarized microscopy, electron microscopy, hematoxylin and eosin staining, and were also sent for analysis of sulfur content (cystine levels). RESULTS: The fetal eyebrows were the only adequate source of hair in the early second trimester. The biopsy samples yielded adequate material for all tests. Polarized microscopy showed characteristic banding patterns, but trichoschisis was not apparent. Cystine levels (19 micromol/l) in the biopsy sample were significantly lower than an age-matched (fresh spontaneous abortion) control (368 micromol/l). CONCLUSION: Prenatal diagnosis of TTD is possible in the second trimester through endoscopically-guided eyebrow biopsy. An adequate amount of hair is present in the eyebrows by then, and the disease is already manifest. Analysis of sulfur content of the hair samples is preferred over polarized or electron microscopy, as many classic microscopic findings of TTD may not be present in the early second trimester.     

Prenatal diagnosis of congenital anomalies--present status and future problems

Technical advances continue to expand the number of genetic disorders that can be diagnosed in utero. The current methods for prenatal diagnosis are as follows: Amniocentesis, fetoscopy, fetal blood sampling, biopsy of fetal skin, and chorionic villus sampling (CVS). The method for growing fetal cells obtained by amniocentesis in short term culture and karyotyping has opened a new area to chromosomal anomalies. By using cultured amniotic fluid cells in larger numbers, it is also possible to diagnose many metabolic disorders. Fetoscopy has been developed which permits the perinatologist to enter the uterus and obtain tissue sample or to actually view the fetus. However, it is very difficult to visualize the fetus directly through fetoscope. Only specific parts of the fetus can be readily identified, but a total examination of surface anatomy is rarely possible. Now ultrasonography with improved resolution can clearly define many major anatomical abnormalities without apparent risk. And also, fetal blood sampling and skin biopsy have been successfully performed under ultrasound guidance rather than under direct fetoscopic visualization. Recently, the advent of fetal blood sampling has made it possible to diagnose genetic disorders which have hitherto been impossible to recognize in the fetus. The main applications are for the prenatal diagnosis of the fetal infection, coagulopathies, hemoglobinopathies, and muscular dystrophies. Several severe genodermatoses result in early death or are associated with significant morbidity. Some of these disorders can be diagnosed in utero with skin biopsies. Harlequin Ichthyosis is a typical case. A positive prenatal diagnosis of Harlequin Ichthyosis was reported.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prenatal presentation of cervical congenital neuroblastoma

OBJECTIVE: To describe a cervical neuroblastoma revealed in the prenatal period. METHOD: We were recently confronted with a case of fetal solid neck mass suggestive of teratoma, which proved postnatally to be a neuroblastoma. Combining this case with a review of recent literature, we have evaluated the diagnostic tools required for increased precision in the prenatal diagnosis and perinatal management of fetal solid neck masses. RESULTS: Detailed ultrasound and MRI of fetal neck and liver, in conjunction with amniocentesis for measurement of homovanillic acid levels, should enable fetal medical practitioners to consider the diagnosis of fetal cervical neuroblastoma. CONCLUSION: Fetal cervical neuroblastoma is an extremely rare condition that has not been previously reported, but should be considered in the presentation of fetal solid neck masses.     

Transabdominal fine needle biopsy from chorionic villi in the first trimester

A technique for sampling first trimester chorionic villi for prenatal diagnosis by transabdominal fine needle biopsy is described. Specimens of chorionic villi were obtained from 49 out of 58 women, a success rate of 84.5 per cent. No fetal or maternal complications were demonstrated in the period before abortion. The procedure is useful for obtaining fetal tissue for culturing, DNA analysis and direct chromosome analysis.     

Recurrent acute fatty liver of pregnancy

The first reported case of recurrent acute fatty liver of pregnancy confirmed by biopsy is described. In this case a high index of suspicion led to an early diagnosis and intervention with resultant improved maternal and fetal outcome. Electron microscopic examination of a liver biopsy specimen proved more beneficial in confirmation of the diagnosis compared with routine microscopic examination.     

Testicular feminization syndrome. Prenatal diagnosis: observations apropos of 2 sisters

The anatomo-clinical aspects and the physiopathology of the feminizing testicle syndrome, are now better known. The prenatal diagnosis of this familial genetic ailment through the determination of the fetal sex by ultrasonography and the study of fetal karyotypes by amniotic fluid analysis or biopsy of trophoblast, is currently possible. Risk groups must be defined in order to ensure a better care for these children.     

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.     

Prenatal diagnosis of long QT syndrome using magnetocardiography: a case report and review of the literature

OBJECTIVES: To investigate the usefulness of magnetocardiography (MCG) in the prenatal diagnosis of fetal long QT syndrome. METHODS: Fetal MCG was recorded in a case of fetal long QT syndrome suspected in utero. The literature on the prenatal diagnosis of fetal long QT syndrome was also reviewed. RESULTS: The MCG was performed at 36 weeks' gestation because sustained fetal bradycardia of 110-120 bpm was detected by cardiotocography. The 64-channel MCG revealed a prolonged fetal corrected QT-interval of 0.57 s. The postnatal electrocardiogram coincided with prenatal MCG. CONCLUSION: An accumulation of cases of prenatally diagnosed long QT syndrome using MCG indicates that MCG may be the most reliable tool for the prenatal diagnosis of long QT syndrome.     

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.