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Biomedical subjects

A Milunsky

Publications and source records attributed to A Milunsky.

At least 37 records · Page 2Linked to original sources
PubMed1997

Genetic counseling in perinatal medicine.

The obstetrician/perinatologist should be well informed about recent advances in human genetics that directly impact patient care. New indications for molecular analyses, specific limitations in their usage, and the need for interpretation of complex laboratory results emphasize the increasingly necessary clinical genetics consultation. The advent of DNA-based presymptomatic or predictive testing introduces dilemmas for patients and their families, and raises medical, legal, and ethical issues in genetic counseling.

Ethics, Medical↗
PubMed1996

Familial supernumerary chromosome and malignancy.

No familial marker chromosome associated with a malignancy has been reported to date. We used fluorescence in situ hybridization (FISH) to characterize a supernumerary marker chromosome 15 ascertained during prenatal diagnosis. This supernumerary chromosome 15 was found to span three generations of a family. Three family members carrying the supernumerary chromosome 15 have also had malignancies, namely, a cystic glioma, leukemia, and thyroid cancer.

Adult↗
PubMed1996

Trisomy 15 mosaicism and uniparental disomy (UPD) in a liveborn infant.

We describe a liveborn infant with uniparental disomy (UPD) with trisomy 15 mosaicism. Third trimester amniocentesis yielded a 46,XX/47,XX,+15 karyotype. Symmetrical growth retardation, distinct craniofacies, congenital heart disease, severe hypotonia and minor skeletal anomalies were noted. The infant died at 6 weeks of life. Peripheral lymphocyte chromosomes were "normal" 46,XX in 100 cells. Parental lymphocyte chromosomes were normal. Skin biopsy showed 47,XX,+15 in 80% of fibroblasts and results were equivalent in fibroblasts from autopsy lung tissue. Molecular analysis revealed maternal uniparental heterodisomy for chromosome 15 in the 46,XX cell line. We describe an emerging phenotype of trisomy 15 mosaicism, confirm that more than one tissue should be studied in all cases of suspected mosaicism, and suggest that UPD be considered in all such cases.

Abnormalities, Multiple↗
PubMed1996

A novel mutation in the MITF gene causes Waardenburg syndrome type 2.

Mutations in the MITF gene on human chromosome 3 have been reported in families with Waardenburg Syndrome Type 2 (WS2), an autosomal dominant disorder responsible for a large proportion of congenital hearing loss. We examined 16 families with WS2 for mutations in the MITF gene. In one four-generation family, we found a novel two-base deletion in exon 6 of the MITF gene at nucleotide position 699. This mutation introduces a frame-shift and stop codon which leads to a truncation of the protein. This mutation is predicted to have phenotypic consequences not withstanding evidence of reduced penetrance and heterogeneity within the family studied.

Binding Sites↗
PubMed1996

Case report: cystic fibrosis and embryonal carcinoma of the testis.

The authors describe a patient with cystic fibrosis and a stage III testicular embryonal cell cancer. Because cystic fibrosis occurs in approximately 1 of 2,500 births and embryonal carcinoma in 3 of 100,000, the likelihood of concurrence for both disorders in the same patient is approximately 1 in 80 million. Involvement of the vas deferens in cystic fibrosis raises the possibility of a fundamental embryologic basis that explains the pathogenesis of this association.

Adult↗
PubMed1996

Molecular cytogenetic characterisation of the first familial case of partial 9p duplication (p22p24).

We report on a father and daughter with a partial 9p duplication, dup(9)(p22p24). Their phenotype, albeit mild, is characteristic of partial trisomy 9p. Fluorescence in situ hybridisation (FISH) was used to characterise further and confirm the G banding finding. This is the first reported instance of trisomy 9p occurring in two successive generations. The duplicated segment in these two patients is among the smallest segments reported. Comparison of our two patients and 144 reported patients with trisomy 9p (partial or complete trisomy) suggests that the 9p22 region may be responsible for the observed phenotype in 9p duplication cases.

Adult↗
PubMed1996

Pulmonary function and clinical observations in men with congenital bilateral absence of the vas deferens.

Congenital bilateral absence of the vas deferens (CBAVD) was once thought to be a distinct clinical entity, but genetic similarities in men with cystic fibrosis (CF) and CBAVD are described increasingly. We evaluated the clinical status, growth and nutritional state, and respiratory function of 18 men with CBAVD to determine whether these men with different CF transmembrane regulator (CFTR) genotypes may have clinical evidence of mild CF. Following a thorough history and examination, pulmonary function tests, sweat test, and renal ultrasound were performed. Genetic evaluation for 50 known CF mutations, screening for private mutations (single-strand conformational polymorphism and direct sequencing), and assay of the length of the polypyrimidine tract in the splice site acceptor of intron 8 was performed. A history of pulmonary disease was present in three, and an additional man had some features suggestive of malabsorption. Results of general physical examination and anthropomorphic measurements were unremarkable in all patients, with a mean (SD) body mass index of 26 (3). Pulmonary function tests of large and small airway function as well as lung volumes were normal in all except one whose results were consistent with moderate asthma. Five men were compound heterozygotes for CFTR mutations, four of whom had positive sweat tests (sweat chloride > 60 mEq/L). Twelve men were heterozygotes for CFTR mutations while no mutations were identified in one man. Although putative etiologic factors may suggest that men with CBAVD and CFTR mutations could be considered within the spectrum of clinical CF, the authors suggest that in men with CBAVD without any other clinical features of CF, the diagnosis of CF may not be made.

Adult↗
PubMed1995

Teratogenicity of high vitamin A intake.

BACKGROUND: Studies in animals indicate that natural forms of vitamin A are teratogenic. Synthetic retinoids chemically similar to vitamin A cause birth defects in humans; as in animals, the defects appear to affect tissues derived from the cranial neural crest. METHODS: Between October 1984 and June 1987, we identified 22,748 pregnant women when they underwent screening either by measurement of maternal serum alpha-fetoprotein or by amniocentesis. Nurse interviewers obtained information on the women's diet, medications, and illnesses during the first trimester of pregnancy, as well as information on their family and medical history and exposure to environmental agents. We obtained information on the outcomes of pregnancy from the obstetricians who delivered the babies or from the women themselves. Of the 22,748 women, 339 had babies with birth defects; 121 of these babies had defects occurring in sites that originated in the cranial neural crest. RESULTS: For defects associated with cranial-neural-crest tissue, the ratio of the prevalence among the babies born to women who consumed more than 15,000 IU of preformed vitamin A per day from food and supplements to the prevalence among the babies whose mothers consumed 5000 IU or less per day was 3.5 (95 percent confidence interval, 1.7 to 7.3). For vitamin A from supplements alone, the ratio of the prevalence among the babies born to women who consumed more than 10,000 IU per day to that among the babies whose mothers consumed 5000 IU or less per day was 4.8 (95 percent confidence interval, 2.2 to 10.5). Using a smoothed regression curve, we found an apparent threshold near 10,000 IU per day of supplemental vitamin A. The increased frequency of defects was concentrated among the babies born to women who had consumed high levels of vitamin A before the seventh week of gestation. CONCLUSIONS: High dietary intake of preformed vitamin A appears to be teratogenic. Among the babies born to women who took more than 10,000 IU of preformed vitamin A per day in the form of supplements, we estimate that about 1 infant in 57 had a malformation attributable to the supplement.

Abnormalities, Drug-Induced↗
PubMed1995

Mutations in PAX3 that cause Waardenburg syndrome type I: ten new mutations and review of the literature.

Waardenburg syndrome (WS) is an autosomal-dominant disorder characterized by sensorineural hearing loss, dystopia canthorum, and pigmentary disturbances, and it represents the most common form of inherited deafness in infants. WS type I is characterized by the presence of dystopia canthorum, while individuals with WS type II have normally-located canthi. WS type III is similar to WS type I but is also characterized by musculoskeletal abnormalities. Defects in the PAX3 gene, a transcription factor expressed during embryonic development, have been shown to cause WS types I and III in several families. In contrast, mutations in PAX3 do not cause WS type II, and linkage of the disease to other chromosomal regions has been demonstrated. We describe 10 additional mutations in the PAX3 gene in families with WS type I. Eight of these mutations are in the region of PAX3, where only one mutation has been previously described. These mutations, together with those previously reported, cover essentially the entire PAX3 gene and represent a wide spectrum of mutations that can cause WS type I. Thus far, all but one of the mutations are private; only one mutation has been reported in two apparently unrelated families. Our analysis thus far demonstrates little correlation between genotype and phenotype; deletions of the entire PAX3 gene result in phenotypes indistinguishable from those associated with single-base substitutions in the paired domain or homeodomain of PAX3. Moreover, two similar mutations in close proximity can result in significantly different phenotypes, WS type I in one family and WS type III in another.

Amino Acid Sequence↗
PubMed1995

Congenital unilateral absence of the vas deferens: a heterogeneous disorder with two distinct subpopulations based upon aetiology and mutational status of the cystic fibrosis gene.

A total of 21 infertile men with congenital unilateral absence of the vas deferens (CUAVD) were studied to determine if this disorder involves mutations in the cystic fibrosis (CF) gene. This hypothesis derives from previous work which has established the genetic commonality of CF and congenital bilateral absence of the vas deferens (CBAVD). Both CF and CBAVD may result from compound heterozygosity for CF mutations. In our patients with unilateral vasal aplasia, 12 had anatomically complete and patent vasa deferentia on the contralateral side, i.e. side of the scrotally palpable vas. No CF mutations were detected in this subgroup. The remaining nine patients had a non-iatrogenic occlusion of the contralateral vas at either the inguinal or pelvic level. In this subgroup, eight out of nine (89%) had a mutation detected in one of their two CF genes. This is the first study to define accurately the clinically and anatomically heterogeneous nature of CUAVD and to begin to clarify the genetic basis of unilateral absence of the vas deferens.

Adult↗
PubMed1995

Cytogenetic and molecular cytogenetic studies of a case of interstitial deletion of proximal 15q.

A 4-month-old child with multiple anomalies was determined to have an interstitial deletion of chromosome 15, i.e., del(15) (q12q14). The deletion appears not to be a typical deletion of 15q12 such as seen in Angelman and Prader-Willi syndromes, but appears to be more distal, involving either loss of all of 15q12 and part of 15q14, or part of 15q12 and most of 15q14. In either case, 15q13 is missing. Fluorescent in situ hybridization with probes for 15 centromere (D15Z), pericentromeric satellite sequences (D15Z1), and chromosome 15 painting probes shows the deleted chromosome to involve only 15 and no other acrocentric chromosome. Hybridization with probes for the AS and PWS loci (D15S11 and GABAB3, Oncor) show both sites to be intact in the deleted 15. The case is compared with two other reports with overlapping interstitial deletions of proximal 15q, neither of which shows typical features of Angelman or Prader-Willi syndromes.

Abnormalities, Multiple↗
PubMed1995

Chromosome 13q deletion with Waardenburg syndrome: further evidence for a gene involved in neural crest function on 13q.

Waardenburg syndrome (WS) is an autosomal dominant disorder characterised by pigmentary abnormalities and sensorineural deafness. It is subcategorised into type 1 (WS1) and type 2 (WS2) on the basis of the presence (WS1) or absence (WS2) of dystopia canthorum. WS1 is always caused by mutations in the PAX3 gene, whereas WS2 is caused by mutations in the microphthalmia (MITF) gene in some but not all families. An association of WS symptoms with Hirschsprung disease (HSCR) has been reported in many families. We report here a patient with characteristics of WS2 and a de novo interstitial deletion of chromosome 13q. We also describe a family with two sibs who have both WS2 and HSCR. In this family, all possible genes for WS and HSCR, but not chromosome 13q, could be excluded. As an association between chromosome 13q and HSCR/WS has been reported previously, these data suggest that there is a gene on chromosome 13q that is responsible for WS or HSCR or both.

Animals↗
PubMed1994

Mutations in PAX3 associated with Waardenburg syndrome type I.

Waardenburg syndrome (WS) types I, II, and III (McKusick #14882, #19351, and #19350) are related autosomal dominant disorders characterized by sensorineural hearing loss, dystopia canthorum, pigmentary disturbances, and other developmental defects. Disease causing PAX3 mutations have been identified in a few families from each of the three disease subtypes, WS-I, WS-II, and WS-III. In others, although the mutations have not been pinpointed, linkage with the PAX3 locus on chromosome 2q35 has been demonstrated. The PAX3 protein is a transcription factor that contains both a paired-domain and a homeodomain DNA binding motif and appears to play a key role during embryogenesis. In this report, we describe two mutations in the human PAX3 gene that cause WS type I. One mutation is a deletion/frameshift in the paired-domain of PAX3 and results in a protein without functional DNA binding domains. The second mutation is a single-base substitution and results in a premature termination codon in the homeodomain of PAX3. This is the first demonstration of a mutation in the homeodomain DNA binding motif in this protein resulting in WS and one of the few examples of a mutation in a homeodomain of any protein that results in human disease.

Amino Acid Sequence↗
PubMed1994

Two transthyretin mutations (glu42gly, his90asn) in an Italian family with amyloidosis.

A family with familial amyloidotic polyneuropathy (FAP) was previously found to have a substitution of asparagine for histidine at position 90 of transthyretin. Members with his90asn developed FAP. However, close examination of the transthyretin gene revealed that glu42gly is coinherited with his90asn in this family. Since glu42gly has already been seen in Japanese FAP patients, and his90asn has been found in Portuguese and German individuals without FAP, we conclude that his90asn is a nonpathogenic variant.

Adult↗
PubMed1993

Characterization of a duplication in the terminal band of 4p by molecular cytogenetics.

An infant with multiple anomalies including small head, large apparently low-set ears, beaked nose, micrognathia, choanal stenosis, proptosis, atrial-septal defect, and left inguinal hernia was found, on chromosome analysis, to have a longer than normal terminal band 4p16 by G and R-banding. In situ hybridization of biotin-labeled DNA probes C39, BJ14, BJ54, BJ19, BJ7, and BJ11 showed them to be duplicated. Probes I14, A157.1, and the telomeric sequence, (TTAGGG)n, which hybridized to the more distal part of 4p16.3, were not duplicated. These results confirm the impression by G and R-banding of a duplication within band 4p16, a region extending from approximately 2.1 Mb from the telomere, proximally, to the junction of 4p16.1 and 4p15.3. This is the smallest confirmed duplication of distal 4p reported to date, with many of the classical findings of dup(4p) syndrome.

Abnormalities, Multiple↗