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G S Pai

Publications and source records attributed to G S Pai.

At least 19 recordsLinked to original sources
PubMed1992

Fluorescence in situ hybridization (FISH) of a whole-arm translocation involving chromosomes 18 and 20 with alpha-satellite DNA probes: detection of a centromeric DNA break?

Fluorescence in situ hybridization (FISH) with alpha-satellite DNA probes was used to study whole-arm chromosome translocation products in a family in which the propositus was shown to have a monosomy 18p/trisomy 20p imbalance. By this approach, we show that the chromosome 18 alpha-satellite DNA block is split into 2 smaller units, whereas the chromosome 20 breakpoint is not included within the alpha-satellite DNA region. We found no evidence to suggest that this split alpha-satellite DNA region has reduced or impaired the function of the centromere or that it contributed to the phenotype of the propositus. The FISH technique critically demonstrated the involvement of a whole-arm translocation in this case and provided accurate identification of breakpoints, which was not possible with standard banding techniques.

Abnormalities, Multiple↗
PubMed1992

Encephalocraniocutaneous lipomatosis and the Proteus syndrome: distinct entities with overlapping manifestations.

We have studied three children with cutaneous (epidermal nevi), subcutaneous (lipomas, plantar skin thickening), vascular (hemangioma, lymphangioma), skeletal (osteoma, exostosis, localized hypertrophy), and neurological (hydrocephaly, lissencephaly, partial agenesis of the corpus callosum) developmental defects associated with the Proteus syndrome and related hamartoneoplastic conditions. We compared our findings in these three patients with those of 50 others with Proteus syndrome and nine with encephalocraniocutaneous lipomatosis (ECCL) reported in the literature. We found that Proteus syndrome and ECCL have distinct identities even though some clinical manifestations are shared by both and a few patients have manifestations of both conditions.

Bone Neoplasms↗
PubMed1992

Paternal uniparental disomy of chromosome 15 in a child with Angelman syndrome.

Angelman and Prader-Willi syndromes are clinically distinct neurobehavioral disorders most commonly resulting from large deletions of chromosome 15q11-q13. The deletions arise differentially during maternal or paternal gametogenesis, respectively. A subgroup of patients with either syndrome have no apparent deletion, and because many such patients with Prader-Willi syndrome display inheritance of two copies of chromosome 15 from the mother only (uniparental disomy; UPD), we suggested that paternal UPD might be found in patients with Angelman syndrome. We report here clinical, cytogenetic, and molecular evidence on the 1 patient with paternal UPD for chromosome 15 who was found in our study population. This represents, to our knowledge, the first patient with paternal UPD to be studied with DNA probes from the chromosome 15q11-q13 critical region. In contrast to our findings for patients with Prader-Willi syndrome, in which maternal UPD was common, our data demonstrate that paternal UPD is infrequent in patients with Angelman syndrome.

Angelman Syndrome↗
PubMed1992

Heterozygote detection through bleomycin-induced G2 chromatid breakage in dyskeratosis congenita families.

We determined the mean number of chromatid breaks per cell (b/c) in the bleomycin-treated lymphocytes of 10 patients with dyskeratosis congenita (DC) and 26 of their relatives to ascertain whether bleomycin sensitivity would distinguish DC heterozygotes from normal individuals. We observed a significantly higher mean number of chromatid b/c in DC patients and obligate heterozygotes (patients versus controls, p less than 0.0001; heterozygotes versus controls, p = 0.0076, Mann-Whitney rank-sum test). Unequivocal heterozygote detection was not possible owing to overlap of the b/c values of patients, heterozygotes, and controls, but our findings provided strong evidence of a link between autosomal recessive as well as X-linked recessive DC mutations and bleomycin sensitivity in homozygous, hemizygous, and heterozygous individuals.

Adolescent↗
PubMed1991

Variability of expression of the orofaciodigital syndrome type I in black females: six cases.

Orofaciodigital syndrome type I (OFD I) includes striking orodental, facial, digital, renal, and central nervous system (CNS) abnormalities. Frequently associated with mental retardation, OFD I is inherited as an X-linked dominant trait, lethal in males. Here, we report the variable expressivity of OFD I in 6 black U.S. females and review findings in 2 previously reported black patients. Only these 8 of over 160 reported cases involve blacks. Abnormalities observed in black patients are similar to those observed in whites, but with specific differences. Only 25% of the blacks had cleft palate and none was observed with midline cleft of the upper lip. Among whites, 80% have cleft palate and 45% midline cleft of the upper lip. These findings suggest that racial genetic factors may protect lip and palate development in blacks, even in the presence of the OFD I gene. CNS abnormalities, including agenesis of the corpus callosum, hydrocephaly, cystic brain lesions, seizures, and mental retardation, were present in 50% of our the cases. This figure is greater than previously reported. Polycystic kidneys were present in 3 of our patients. Including a previously reported patient, 50% of the black OFD I patients show polycystic kidneys. Hyperplastic and supernumerary frenula, with or without brachydactyly, have been shown to be strong diagnostic criteria in our patients. New findings reported here include intracranial berry aneurysm, periodontal disease, and lip pits. Clinicians treating these patients should be aware of the pleiotropic manifestations of the syndrome, which may include renal and CNS anomalies. Ultrasonic and computed tomography scan studies are indicated in patients diagnosed with OFD I.

Adolescent↗
PubMed1990

Multiple rhabdomyomatous mesenchymal hamartomas of skin.

A case of multiple rhabdomyomatous mesenchymal hamartomas is presented. The patient is a black male infant, the product of an uncomplicated term gestation and delivery. At birth, there were numerous polyps distributed over the periorbital and periauricular areas bilaterally. Some appeared fingerlike with constrictions below their tips. Others were branched or globular in shape. These projections showed spontaneous and independent movement, particularly during feedings. On histopathologic examination, the polyps were covered by squamous epithelium and contained normal follicular units. Bundles of skeletal muscle were present in the reticular dermis, extending into the subcutis. Regular cross-striations were seen in these muscle fibers. In some specimens, the muscle bundles formed a solid, central core. Skeletal muscle histochemical stains confirmed the presence of both types 1 and 2 muscle fibers. Electron microscopy revealed a normal skeletal muscle banding pattern. This case is the first report of multiple rhabdomyomatous mesenchymal hamartomas of skin. Functional skeletal muscle with spontaneous movement is part of the clinical picture.

Diagnosis, Differential↗
PubMed1990

Enhanced G2 chromatid radiosensitivity in dyskeratosis congenita fibroblasts.

Dyskeratosis congenita (DC) is an inherited disorder characterized by reticular pigmentation of the skin, dystrophic nails, mucosal leukoplakia, and a predisposition to cancer in early adult life. In the majority of cases, DC is an X-linked recessive trait. However, one or more autosomal form(s) of DC may exist. Although excessive spontaneous chromatid breakage has been reported in DC, it is not a consistent cytological marker for this disorder. We examined the frequency and specificity of X-irradiation-induced G2 chromatid breakage in fibroblasts from three unrelated DC patients (two males and one female). Metaphase cells from DC patients had significantly more chromatid breaks (16-18-fold and 17-26-fold at 50 and 100 rad X-irradiation, respectively) and chromatid gaps (10-12-fold and 6-7-fold at 50 and 100 rad, respectively) than those from two different controls. Analysis of banded chromosomes revealed a nonrandom distribution of chromatid aberrations in DC but not in controls, a distribution corresponding to some of the known breakpoints for cancer-specific rearrangements, constitutive fragile sites, and/or loci for cellular proto-oncogenes. The significance of this finding for cancer predisposition in DC patients is uncertain, but the increased susceptibility of X-irradiation-induced chromatid breakage may serve as a cellular marker of diagnostic value.

Cell Line↗
PubMed1989

Etiologic heterogeneity in dyskeratosis congenita.

Most patients with dyskeratosis congenita [DC or Zinsser-Cole-Engman syndrome] are males hemizygous for an X-linked recessive mutation. However, one or more autosomal form(s) of DC may exist. We have studied a 6-year-old black girl with the characteristic triad of nail dystrophy, cutaneous and mucosal pigmentary changes, and bone marrow failure. Severe microcephaly, mental retardation, cerebellar hypoplasia, and purple discoloration of the tongue were other manifestations not usually seen in DC. Comparison of our patient's phenotype with that of 5 other sporadic and 10 familial cases of DC in females showed that the autosomal and X-linked phenotypes are not distinguishable in the absence of a suggestive pedigree pattern. Additional cases of DC need to be studied to better elucidate the apparent causal heterogeneity in this syndrome.

Bone Marrow Diseases↗
PubMed1989

Bleomycin hypersensitivity in dyskeratosis congenita fibroblasts, lymphocytes, and transformed lymphoblasts.

We studied the responses of several dyskeratosis congenita (DC) cell lines to the DNA strand-cleaving and base-damaging agent bleomycin. Fibroblasts, peripheral blood lymphocytes, and transformed lymphoblasts of six DC patients and an obligate DC heterozygote showed more chromatid breaks than did respective controls exposed to various concentrations of bleomycin during the G2 phase of the cell cycle (P less than 0.0001). Unsynchronized DC fibroblasts in culture also showed decreased survival, compared to normals, following bleomycin treatment. DC lymphocytes treated with bleomycin for the final 24 h of culture showed more chromatid- and chromosome-type damage than did normals (P less than 0.0001) or G0-treated DC lymphocytes. Spontaneous chromosome breakage was normal in all six DC cell lines. The ability to distinguish affected and heterozygous DC cells without spontaneous chromosome instability from normals on the basis of their bleomycin hypersensitivity provides a marker for future studies of the pathogenesis of this disorder.

Bleomycin↗
PubMed1988

Idiopathic multicentric osteolysis: report of two new cases and a review of the literature.

Idiopathic multicentric osteolysis is a rare skeletal disorder, usually presenting in early childhood with a clinical picture mimicking juvenile rheumatoid arthritis. Progressive destruction of the carpal and tarsal bones usually occurs and other bones may also be involved. Chronic renal failure is a frequent component of this syndrome. Mental retardation and minor facial abnormalities have been noted in some patients. We report on 2 unrelated, sporadic cases, one with facial anomalies and the other with nephropathy. Our second patient is the first black child to be diagnosed with this disease. The mode of presentation, differential diagnosis, and natural history of this disorder are briefly reviewed.

Child↗
PubMed1988

Incidental detection of premature centromere separation in amniocytes associated with a mild form of Roberts syndrome.

Premature centromere separation (PCS) was detected in amniocytes after an amniocentesis was done because of markedly elevated maternal serum alpha-fetoprotein values in a healthy primiparous young woman. PCS has been associated with the Roberts-SC phocomelia syndrome (RS). By 23 weeks' gestation, ultrasonic evaluations did not reveal abnormal fetal development. The pregnancy continued and a male infant was born with mild manifestations of RS. PCS was confirmed in cord blood lymphocytes. This case illustrates that PCS, when detected in amniotic fluid cell cultures, requires a thorough evaluation.

Adult↗
PubMed1987

Median cleft of the upper lip associated with lipomas of the central nervous system and cutaneous polyps.

An unusual combination of three rare developmental anomalies, ie, complete median cleft lip, cutaneous polyps, and midline lipomas of the central nervous system, was discovered in a male newborn. Inguinal hernia, cryptorchidism, and clinodactyly of the fifth fingers were other features. His mother was found to have clinodactyly, antimongoloid slant to her palpebral fissures, and computed tomography (CT) scan evidence of asymptomatic hydrocephaly. Family history and clinical investigations did not reveal any clues to etiology. This combination of findings may represent a new syndrome or another expression of frontonasal dysplasia.

Brain Neoplasms↗
PubMed1987

Segregation of inverted chromosome 13 in families ascertained through liveborn recombinant offspring.

In humans pericentric inversions are rare structural chromosome abnormalities. Reproductive consequences of inversion heterozygosity depend upon many variables such as the chromosomes involved, the location of breakpoints, frequency of crossovers in the inverted segment, functional impairment of the gametes produced, and the viability of unbalanced zygotes that form. Therefore, each pericentric inversion may be studied as a unique mutation. This paper analyzes the segregation of inversion 13 chromosomes resulting from breaks at bands 13p12 and 13q21/22 in 11 apparently unrelated families. Ten of these families were ascertained through malformed fetuses or infants with a recombinant 13 duplication q, deletion p chromosome.

Abnormalities, Multiple↗