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Biomedical subjects

H J Stern

Publications and source records attributed to H J Stern.

At least 19 recordsLinked to original sources

Novel approach to the molecular diagnosis of Marfan syndrome: application to sporadic cases and in prenatal diagnosis.

Marfan syndrome is an autosomal dominant disorder affecting the skeletal, ocular, and cardiovascular systems. Defects in the gene that encodes fibrillin-1 (FBN1), the main structural component of the elastin-associated microfibrils, are responsible for the disorder. Molecular diagnosis in families with Marfan syndrome can be undertaken by using intragenic FBN1 gene markers to identify and track the disease allele. However, in sporadic cases, which constitute up to 30% of the total, DNA-based diagnosis cannot be performed using linked markers but rather requires the identification of the specific FBN1 gene mutation. Due to the size and complexity of the FBN1 gene, identification of a causative Marfan syndrome mutation is not a trivial undertaking. Herein, we describe a comprehensive approach to the molecular diagnosis of Marfan syndrome that relies on the direct analysis of the FBN1 gene at the cDNA level and detects both coding sequence mutations and those leading to exon-skipping, which are often missed by analysis at the genomic DNA level. The ability to consistently determine the specific FBN1 gene mutation responsible for a particular case of Marfan syndrome allows both prenatal and pre-implantation diagnosis, even in sporadic instances of the disease.

Adult↗

Prenatal diagnosis of Smith-Lemli-Opitz syndrome in a pregnancy with low maternal serum oestriol and a sex-reversed fetus.

A cytogenetically normal male fetus was subsequently found to have female external genitalia, a cardiac malformation and mid-trimester intra-uterine growth retardation by ultrasound examination. The maternal serum oestriol level was low. The combination of low oestriol and sonographic findings suggested Smith Lemli Opitz syndrome (SLO), which was confirmed by a markedly increased amniotic fluid level of 7-dehydrocholesterol. We review the differential diagnosis of apparent sex reversal in a fetus and low maternal serum oestriol level. To further examine the specificity of low maternal oestriol level as a marker for SLO a follow-up study of 12141 pregnancies screened for Down syndrome using three biochemical markers: alpha-fetoprotein, beta-human chorionic gonadotrophin and oestriol was performed. 26 pregnancies had an oestriol level that was 0.25 MoM or less. SLO was not diagnosed clinically in any of the liveborn children ascertained through a low maternal oestriol level. Nine of the pregnancies ended in spontaneous miscarriage. Although the frequency of SLO in pregnancies with low maternal oestriol levels or sex-reversed fetuses is unknown, the diagnosis of SLO should, nevertheless, be considered in both clinical settings.

Adult↗

Transcatheter occlusion of the patent ductus arteriosus: use of the retrievable coil device.

The Cook Retrievable Embolization Coil has been designed to improve delivery and positioning during coil embolization of the patent ductus arteriosus (PDA). We report our experience with the use of this new technique. Twenty-eight patients underwent coil embolization of a PDA using the retrievable system. The median patient age was 4.5 years (range, 2 months to 33 years), median weight 17.2 kg (range, 3.1-100 kg). The mean minimum diameter was 1.1 mm (range, 0.3-3.8 mm). One or two Cook Retrievable Embolization Coils were implanted in each PDA. Successful delivery was achieved in 27 cases. There was no shunt by angiography in 19 of the patients (70%). Color echocardiography documented no shunt in 13 of 17 patients (77%). The retrievable coil system represents a successful method of PDA occlusion with good control of coil positioning and delivery.

Adolescent↗

New insights into the phenotypes of 6q deletions.

Deletions of chromosome 6q are rare. We report 3 new patients with 6q deletions. Case 1 is a male with an interstitial deletion [del(6)(q13q14.2)], hypotonia, speech delays, and minor anomalies. Case 2 is a male with an interstitial deletion [del(6)(q16.2q22.32)] and malformations, including truncus arteriosus and bilateral oligodactyly. Case 3 is a male with a terminal deletion [del(6)(q25.2)] with retinal pits, hydrocephalus, atrioventricular canal, and hydronephrosis. The findings in our patients and those from 57 previously reported cases demonstrated 3 phenotypic groups associated with 6q deletions. Group A [del(6)(q11-q16)] had a high incidence of hernias, upslanting palpebral fissures, and thin lips with lower frequency of microcephaly, micrognathia, and heart malformations. Group B [del(6)(q15-q25)] was associated with increased intrauterine growth retardation, abnormal respiration, hypertelorism, and upper limb malformations. Group C [del(6)(q25-qter)] was associated with retinal abnormalities, cleft palate, and genital hypoplasia. The only universal finding among all patients with 6q deletions was mental retardation. Other findings common to all 3 groups included ear anomalies (90%), hypotonia (82%), and postnatal growth retardation (68%).

Adult↗

Sudden neonatal death in carnitine transporter deficiency.

A newborn infant died suddenly and unexpectedly on day 5 of life. Postmortem investigations led to a suspicion of carnitine transporter deficiency, a diagnosis supported by the finding that both parents are heterozygotes for this disorder. The fasting stress caused by poor breast-feeding with no formula supplements and, possibly, the vegetarian diet of the mother were likely the critical factors leading to neonatal death, an outcome previously not described in this disorder.

Adipose Tissue↗

Neurodevelopmental profile of infants and toddlers with oculo-auriculo-vertebral spectrum and the correlation of prognosis with physical findings.

We studied the neurodevelopmental profile of infants and toddlers with oculo-auriculo-vertebral spectrum (OAV) and determined if certain physical manifestations were indicative of a poor neurodevelopmental prognosis. Twenty-four patients with OAV, aged birth to 57 months, were seen in the Department of Medical Genetics at Children's National Medical Center for multidisciplinary evaluations, including neurodevelopmental assessments. Fifty-eight percent of these children scored more than 2 standard deviations below the mean in at least one domain of development. There was no difference in developmental outcome of boys versus girls, children affected unilaterally on the right side versus left side, and those with severe clinical manifestations versus those with a milder form. Children with OAV and abnormal muscle tone had lower cognitive, gross motor, and expressive language scores (P = 0.05, P = 0.002, and P = 0.02, respectively). Those affected bilaterally had lower cognitive, fine motor, receptive language, and expressive language scores (P = 0.06, P = 0.03, P = 0.03, P = 0.02, respectively). Children with cervical spine abnormalities had lower cognitive, fine motor, and expressive language scores (P = 0.02, P = 0.04, and P = 0.04, respectively). We conclude that infants and toddlers with OAV are at increased risk for neurodevelopmental delay, especially those with abnormal muscle tone, bilateral involvement, and cervical vertebral anomalies. The complexity of the neurodevelopmental problems is strongly suggestive of central nervous system disturbances. Patients with OAV need comprehensive evaluation by a multidisciplinary team to define potential neurodevelopmental delays, allow for early intervention services, and promote an optimal developmental outcome.

Child, Preschool↗

Prolonged survival in pyruvate carboxylase deficiency: lack of correlation with enzyme activity in cultured fibroblasts.

OBJECTIVE: To report the clinical history and laboratory evaluation of a patient presenting with lactic acidosis secondary to pyruvate carboxylase deficiency. METHODS AND RESULTS: Enzyme analysis of cultured skin fibroblasts revealed 2-5% of normal pyruvate carboxylase activity. Although most patients with this condition die in early infancy, this child has survived to age 8-1/2 years, with only occasional episodes of metabolic acidosis, usually responding rapidly to intravenous hydration and bicarbonate. Despite having a seizure disorder and moderate mental retardation, he continues to thrive and make progress in his acquisition of motor and language skills. Of the 35 patients described in the literature with pyruvate carboxylase deficiency, only two other patients have lived beyond 5 years of age. CONCLUSION: There does not seem to be a correlation of prolonged survival with residual pyruvate carboxylase activity on assay of cultured fibroblasts. Possible explanations for this patient's prolonged survival include tissue heterogeneity, increased residual enzyme activity in vivo, or partial stabilization of the enzyme by supplemental biotin.

Acidosis, Lactic↗

Variable prenatal appearance of osteogenesis imperfecta.

Osteogenesis imperfecta is a heterogeneous group of disorders of type I collagen with both lethal and nonlethal forms. Prenatal sonographic findings in affected fetuses are variable and depend on the severity of the disease. Six cases of osteogenesis imperfecta in which prenatal sonography had been performed were reviewed. Two cases of lethal type II osteogenesis imperfecta revealed short femurs at 16 to 17 weeks' gestation with development of bowing and fractures by 19 weeks' gestation. Four fetuses with the nonlethal type III or IV had femoral bowing with or without shortening in the late second or third trimester with grossly normal mineralization. Fractures in this latter group did not develop until 1 to 12 months after delivery. Understanding the progressive nature and variability of osteogenesis imperfecta is crucial in the prenatal diagnosis and management of this disease.

Adolescent↗

Principles and applications of the polymerase chain reaction.

The invention of the polymerase chain reaction (PCR) technique for nucleic acid amplification has had a major impact on many diverse areas of both basic and clinical research. Since its inception in 1985, reports on a wide variety of applications for PCR have received much attention in scientific and medical literature. This technology has been shown to have wide applicability to the diagnosis of human disease, including such diverse areas as infectious diseases, genetic disorders, and cancer. This article presents a broad overview of the principles of PCR including generic concerns that must be addressed when using or designing PCR-based assays. The application of PCR-based assays for the diagnosis of genetic disorders and for infectious disease testing is also discussed.

Communicable Diseases↗

New autosomal recessive syndrome of sparse hair, osteopenia, and mental retardation in Mennonite sisters.

We report on 2 Mennonite sisters with a syndrome of sparse hair, osteopenia, mental retardation, minor facial abnormalities, joint laxity, and hypotonia. Their asymptomatic consanguineous parents (inbreeding coefficient F = 1/64) have 6 other offspring, 3 of whom died in infancy of type II osteogenesis imperfecta (OI), and 3 of whom are normal. We analyzed collagens synthesized by cultured fibroblasts from these 2 sisters and their parents and detected no major abnormalities. Results of chromosomal and metabolic evaluations including amino acid analysis of plasma, urine, and hair were unremarkable. A literature search and survey of a computerized syndrome identification database did not disclose an identical phenotype. The sisters bear superficial resemblance to several known syndromes which we excluded on clinical and/or biochemical grounds. We conclude that they represent a new autosomal recessive syndrome, distinct from type II OI and perhaps unique to the Mennonite population or to this particular family.

Bone Diseases, Metabolic↗

Clinical variability of type 1 neurofibromatosis: is there a neurofibromatosis-Noonan syndrome?

Detailed clinical, ophthalmological, and molecular studies were performed on a multigeneration family in which there were many subjects with type 1 neurofibromatosis, a common autosomal dominant disorder. Affected family members displayed a wide range of clinical findings including, in two subjects, features seen in Noonan syndrome (triangular facies, downward slanting palpebral fissures, micrognathia, short stature, and learning disability). Subjects have been described previously whose features have overlapped with neurofibromatosis and Noonan syndrome, and it has been suggested that these persons might represent a separate condition. DNA haplotype analysis showed linkage of the neurofibromatosis phenotype seen in this family to the proximal long arm of chromosome 17 in the region where the type 1 neurofibromatosis gene has been mapped. These results imply that the Noonan phenotype seen in some patients with type 1 neurofibromatosis might be the result of variable or variant expression of the neurofibromatosis gene on chromosome 17. The possible role of non-specific factors, such as fetal hypotonia, in producing the neurofibromatosis-Noonan phenotype needs further investigation. The availability of closely linked and intragenic molecular markers for neurofibromatosis could potentially be useful in the diagnosis and characterisation of patients and families with atypical forms of neurofibromatosis.

Adult↗

Atelosteogenesis type III: a distinct skeletal dysplasia with features overlapping atelosteogenesis and oto-palato-digital syndrome type II.

We present 5 cases of a short-limb dwarfism syndrome whose manifestations overlap those of atelosteogenesis and oto-palato-digital syndrome Type II. Clinical, radiographic, genetic, and histologic data are presented which demonstrate differences between our patients and previously reported cases of these other conditions. We conclude that the disorder seen in these children represents a distinct chondrodysplasia for which we propose the name atelosteogenesis Type III.

Bone and Bones↗

Steroid sulfatase gene in XX males.

The human X and Y chromosomes pair and recombine at their distal short arms during male meiosis. Recent studies indicate that the majority of XX males arise as a result of an aberrant exchange between X and Y chromosomes such that the testis-determining factor gene (TDF) is transferred from a Y chromatid to an X chromatid. It has been shown that X-specific loci such as that coding for the red cell surface antigen, Xg, are sometimes lost from the X chromosome in this aberrant exchange. The steroid sulfatase functional gene (STS) maps to the distal short arm of the X chromosome proximal to XG. We have asked whether STS is affected in the aberrant X-Y interchange leading to XX males. DNA extracted from fibroblasts of seven XX males known to contain Y-specific sequences in their genomic DNA was tested for dosage of the STS gene by using a specific genomic probe. Densitometry of the autoradiograms showed that these XX males have two copies of the STS gene, suggesting that the breakpoint on the X chromosome in the aberrant X-Y interchange is distal to STS. To obtain more definitive evidence, cell hybrids were derived from the fusion of mouse cells, deficient in hypoxanthine phosphoribosyltransferase, and fibroblasts of the seven XX males. The X chromosomes in these patients could be distinguished from each other when one of three X-linked restriction-fragment-length polymorphisms was used. Hybrid clones retaining a human X chromosome containing Y-specific sequences in the absence of the normal X chromosome could be identified in six of the seven cases of XX males.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Fryns syndrome: an autosomal recessive disorder associated with craniofacial anomalies, diaphragmatic hernia, and distal digital hypoplasia.

Fryns syndrome is an autosomal recessive, genetically determined condition with variable expression, which includes abnormal facial features, diaphragmatic hernia, distal limb abnormalities, and malformations of the cardiovascular, gastrointestinal, genitourinary, and central nervous systems. Five cases of children with Fryns syndrome, including an example of familial recurrence and a case of long-term survival, are described. This report brings to 25 the number of cases reported in the literature and further serves to illustrate the clinical variability of this disorder.

Abnormalities, Multiple↗

Autosomal dominant transmission of isolated congenital vertical talus.

We report vertical transmission of isolated congenital vertical talus through three generations of a Honduran family. Five of nine affected family members were examined and the diagnosis was confirmed radiographically. There was incomplete penetrance in one clinically unaffected woman with two affected children. Bilateral and unilateral involvement was seen with a wide range of severity. Based on this family and on cases reviewed from the literature, we propose that isolated congenital vertical talus can be inherited as an autosomal dominant trait with variable expression and incomplete penetrance.

Child↗