Prader-Willi syndrome: current understanding of cause and diagnosis

Prader-Willi syndrome (PWS) is characterized by hypotonia, obesity, hypogonadism, short stature, small hands and feet, mental deficiency, a characteristic face, and an interstitial deletion of the proximal long arm of chromosome 15 in about one-half of the patients. The incidence is estimated to be about 1 in 25,000, and PWS is the most common syndromal cause of human obesity. DNA abnormalities, usually deletions or duplications of chromosome 15, have been identified in individuals with PWS with or without recognizable chromosome 15 deletions. Paternal origin of the chromosome 15 deletion by cytogenetic and DNA studies has been found in nearly all PWS individuals studied. No cytogenetic evidence for chromosome breakage has been identified, although an environmental cause (e.g., paternal hydrocarbon-exposed occupations) of the chromosome 15 abnormality has been proposed. PWS patients with the chromosome 15 deletion are more prone to hypopigmentation compared with PWS individuals with normal chromosomes, but no other clinical differences are consistently identified between those with and without the chromosome deletion. Anthropometric, dermatoglyphic, and other clinical findings indicate homogeneity of PWS patients with the chromosome deletion and heterogeneity of the nondeletion patients. A review of our current understanding of the major clinical, cytogenetic, and DNA findings is presented, and clinical manifestations and cytogenetic abnormalities are summarized from the literature.

Focal sclerosing glomerulonephritis in a child with Laurence-Moon-Biedl syndrome

We report a 6-year-old white male with Laurence-Moon-Biedl syndrome and focal sclerosing glomerulonephritis (FSGN). To our knowledge, FSGN has not been reported previously in patients with this syndrome. We wish to alert the clinician to the wide variety of renal abnormalities that can be seen in patients with this rare, autosomal recessive disorder.

Genetic imprinting suggested by maternal heterodisomy in nondeletion Prader-Willi syndrome

Prader-Willi syndrome (PWS) is the most common form of dysmorphic genetic obesity associated with mental retardation. About 60% of cases have a cytological deletion of chromosome 15q11q13 (refs 2, 3). These deletions occur de novo exclusively on the paternal chromosome. By contrast, Angelman syndrome (AS) is a very different clinical disorder and is also associated with deletions of region 15q11q13 (refs 6-8), indistinguishable from those in PWS except that they occur de novo on the maternal chromosome. The parental origin of the affected chromosomes 15 in these disorders could, therefore, be a contributory factor in determining their clinical phenotypes. We have now used cloned DNA markers specific for the 15q11q13 subregion to determine the parental origin of chromosome 15 in PWS individuals not having cytogenetic deletions; these individuals account for almost all of the remaining 40% of PWS cases. Probands in two families displayed maternal uniparental disomy for chromosome 15q11q13. This is the first demonstration that maternal heterodisomy--the presence of two different chromosome 15s derived from the mother--can be associated with a human genetic disease. The absence of a paternal contribution of genes in region 15q11q13, as found in PWS deletion cases, rather than a mutation in a specific gene(s) in this region may result in expression of the clinical phenotype. Thus, we conclude that a gene or genes in region 15q11q13 must be inherited from each parent for normal human development.

Prenatal diagnosis and carrier detection of a cryptic translocation by using DNA markers from the short arm of chromosome 5

DNA markers from the short arm of chromosome 5 were used to examine a large family in which a microscopically undetectable translocation was segregating. In addition to confirming that three retarded children were hemizygous for loci distal to 5p14, these analyses identified five individuals as being carriers of the balanced translocation. The use of molecular probes provided informed genetic counseling to the family for the first time. With the DNA markers from 5p, prenatal diagnosis was performed on two fetal chorionic villus samples, both of which were found to have unbalanced karyotypes. The identification of translocation carriers was complicated by recombination between the small translocated segment of 5p and the corresponding region on the normal homologue, which changed the haplotype of the translocated 5p segment.

Hypopigmentation: a common feature of Prader-Labhart-Willi syndrome

In order to determine the frequency and characterization of hypopigmentation in Prader-Labhart-Willi syndrome (PLWS), clinical, cytogenetic and biochemical findings are reported in 56 PLWS individuals. Forty-eight percent of the individuals with PLWS met the criteria for hypopigmentation. Hypopigmentation in PLWS individuals appears to be as common as previously recognized features such as behavioral problems and dental abnormalities. Significant differences in hair color, sun sensitivity, and complexion were found between those PLWS patients with the chromosome 15 deletion and those with normal chromosomes. Individuals with the deletion frequently had lighter hair color, more sun sensitivity, and fairer complexion than did either other family members or nondeletion PLWS patients. No significant differences in biochemical findings (phenylalanine, tyrosine, catecholamines, or beta-melanocyte-stimulating hormone) were found between deletion and nondeletion PLWS patients or between hypopigmented and normally pigmented patients. The data suggest that a gene(s) controlling the activity of tyrosinase or other enzymes required for melanin production is located on proximal 15q.

Occupational hydrocarbon exposure among fathers of Prader-Willi syndrome patients with and without deletions of 15q

Prader-Willi syndrome (PWS) is a multiple-anomaly disorder in which 50%-70% of cases are associated with a de novo interstitial deletion [del 15(q11-13)] on prometaphase cytogenetic analysis, the remainder having apparently normal chromosomes. In most instances, the paternally derived chromosome has become deleted in the affected child, suggesting the possibility of a predisposing environmental factor. Strakowski and Butler found an increased incidence of paternal periconceptional employment in hydrocarbon-exposing occupations in this population. This observation may suggest a causal relationship to PWS. To determine whether this association may distinguish the cytogenetically different groups, we identified 81 patients with the disorder who were physically and cytogenetically examined in three centers, and we compared the frequency of possible periconceptional occupational hydrocarbon exposure between fathers of patients who demonstrate a 15q deletion and those who do not. There was no statistically significant difference between the cytogenetically different groups. In both groups, approximately half of the fathers had been employed in hydrocarbon-exposing jobs. These findings suggest lack of etiologic heterogeneity between the cytogenetically different groups for PWS and affirm the need to seek submicroscopic deletions through molecular genetic studies. These data also provide additional evidence that hydrocarbon exposure among fathers of children with PWS may be causally related to the disorder, and they also suggest the need for more accurate assessment of exposure via a large, controlled study.

Analysis of chromosome breakage in the Prader-Labhart-Willi syndrome

Analysis of chromosome breakage with mitomycin C (MMC) and folate-deficient culture conditions was undertaken on 18 Prader-Labhart-Willi syndrome (PLWS) patients (10 with 15q12 deletion [5 females, 5 males; mean age = 17.9 yr, range of 0.3 to 40 yr] and 8 without deletion [2 females, 6 males; mean age = 18.6 yr, range of 7 to 26 yr]), 21 PLWS parents with an average age of 39.2 yr and a range of 25 to 70 yr (12 fathers [8 fathers of PLWS children with the 15q12 deletion and 4 fathers of PLWS children with normal chromosomes] and 9 mothers [4 mothers of PLWS children with the 15q12 deletion and 5 mothers of PLWS children with normal chromosomes]), and age-matched control individuals. There was no difference between PLWS patients and control individuals in the number of chromosome and chromatid aberrations in cells grown at 48 and/or 96 hr in either 20 ng/ml or 50 ng/ml of MMC or between the PLWS parents and control individuals in cells grown in 50 ng/ml MMC for 96 hr, although a small increase (P less than 0.05) in chromosome breakage was found in cells from the total PLWS parental group compared with control individuals exposed for 48 hr in 50 ng/ml MMC. There was also no significant difference in chromosome fragile site frequency in cells grown in folate-deficient culture conditions in PLWS patients, their parents, or controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of age, sex and multiple endocrine neoplasia type-II on silver stained nucleolar organizer regions

Silver stained nucleolar organizer regions (AgNORs) were studied in phytohemagglutinin (PHA)-stimulated lymphocytes from 55 Caucasian control individuals (34 females with average age of 24 years and age range 19 weeks gestation to 87 years; 21 males with average age of 31 years and age range 29 weeks gestation to 72 years) and 13 individuals (7 females, 6 males; average age 38.8 years with age range 25-58 years) with multiple endocrine neoplasia-type II (MEN-II), an autosomal dominant malignancy with increased chromosome breakage. For the first time, AgNORs were examined in lymphocytes from normal fetuses and patients with MEN-II in order to determine the effects of age, sex or malignancy on the number of AgNORs. No significant difference in the average number of AgNORs were found in fetal cells (8.2 +/- S.D. 0.7/cell) when compared with cells from older individuals including those over 65 years of age (8.0 +/- S.D. 0.8/cell). There was a statistically significant negative correlation (P less than 0.05) between the modal number of AgNORs on G but not D chromosomes in both males and females. A negative correlation was also found between the mean number of AgNORs and age but was not statistically significant. The average number of AgNORs in the MEN-II individuals was 8.5 +/- S.D. 0.7/cell, which was not significantly different than 8.2 +/- S.D. 0.7/cell observed in age-matched control subjects.

Metacarpophalangeal pattern profile analysis in fragile X syndrome

We analyzed the metacarpophalangeal pattern profile (MCPP) on 18 male individuals from 16 families with fragile X--fra (X), or Martin-Bell--syndrome and calculated a mean syndrome profile. Fourteen of 18 individuals with fra (X) syndrome had significant positive correlations which indicated clinical homogeneity. Discriminant analysis of individuals with fra (X) syndrome compared with a sample of normal individuals produced a correct classification rate of 88% based on a function of 3 MCPP variables that may provide a useful tool in screening individuals for the fra (X) syndrome. Discriminant and correlation analyses of individuals with Sotos sequence and individuals with fra (X) syndrome did not identify MCPP similarities. Therefore, there was no MCPP evidence in our study of patients with Sotos sequence and fra (X) chromosome expression.

Do some patients with fragile X syndrome have precocious puberty?

We report on an 8 1/2-year-old white girl with fra (X) syndrome; she had mental deficiency, hyperactivity, speech disturbances, slightly prominent ears, mild joint laxity and 20% fra (X) expression. Additional findings include idiopathic precocious puberty and a right ovarian cyst. Ovarian cysts have been reported previously in heterozygous females, but to our knowledge idiopathic precocious puberty is a new finding in this syndrome. Whether precocious puberty is a coincidental finding in this patient or a previously unreported manifestation of the fra (X) syndrome is not clear.

The use of early simultaneous percutaneous umbilical blood sampling (PUBS) and amniocentesis for prenatal fragile X chromosome diagnosis

Early simultaneous percutaneous umbilical blood sampling (PUBS) and amniocentesis for prenatal diagnosis were undertaken for the first time in a 17-week gestation fetus at risk for the fragile X [fra (X)] syndrome. Metaphase spreads from 300 fetal lymphocytes were examined within 5 days following PUBS, while approximately 5 weeks were required for the analysis of 148 amniocytes. The chromosomes were interpreted as normal (46,XX) and the fetus as fragile X-negative at the time of prenatal diagnosis. This was cytogenetically confirmed after delivery of a healthy term female infant. Our results suggest that early PUBS may become a useful adjunct to amniocentesis because of shorter culture time and earlier diagnosis.

Acrodysostosis: report of a 13-year-old boy with review of literature and metacarpophalangeal pattern profile analysis

We report on a 13-yr-old boy with acrodysostosis, a review of 30 cases in the literature, and metacarpophalangeal pattern profile (MCPP) analysis. The prominent manifestations (present in greater than 75% of cases) of this condition include nasal and maxillary hypoplasia, peripheral dysostosis, first ray hyperplasia of the foot, acromesomelic brachymelia, decreased interpedicular distance, advanced skeletal maturation and mental retardation. Results of chromosome studies have been normal. An autosomal dominant inheritance pattern was reported in two families. Maternal and paternal ages were 2 and 3 yr, respectively, above the average age of the general parent population, which suggests that advanced parental age may be a factor in the cause of this condition. A characteristically abnormal MCPP was found in our patient and in 16 additional cases studied from the literature. A mean MCPP was developed for the syndrome. MCPP analysis may be useful as a diagnostic tool in patients suspected to have acrodysostosis.

P component in the synovium in rheumatoid and osteoarthritis

P component is present in amyloid deposits, normal serum, and normal tissues in relation to elastic fibres. Its pathological role in inflammatory synovitis was investigated. Its distribution was determined immunohistologically in 33 synovia: 15 rheumatoid; seven osteoarthritic; seven traumatic controls; and four infected biopsy specimens. P component was present in two circumscribed distributions: extracellular fibrils in dense fibroelastic tissue of the more fibrotic synovia; and in the arterial wall, where it was confined to a single elastic lamina in some cases and in others showed reduplication and fragmentation. These were not related to amyloid material. It shows no disease specificity, but P component categorises the nature of the pathological reaction and is typically in biopsy specimens showing the development of chronic fibrosis. There was close codistribution of P component with elastic tissue, though this was not absolute. P component had a different distribution from C reactive protein (in synovial lining cell layer), and fibronectin, which was absent from fibrotic areas. Understanding the pathological interactions of P component may help elucidate why some synovial reactions remain inflammatory and other progress to chronic fibrosis.

Ultrastructural localization of antigens recognized by the monoclonal antibodies MB1, MB2, MT1, UCHL1, and TAL 1B5

In this study the ultrastructural localization of antigens recognized by novel antibodies that allow the recognition of lymphoid antigens in conventionally fixed and wax-embedded sections was investigated. MT1, MB1, and UCHL1 recognize antibodies restricted to the cell membrane, whereas the antigen recognized by MB2 is present only in the cytoplasm. These distributions are different from that of immunoreactivity with TAL 1B5 (anti-HLA DR), which is present both on the cell membrane and in the cytoplasm. The significance of these findings is discussed.

Metacarpophalangeal pattern profile analysis in Sotos syndrome: a follow-up report on 34 subjects

Metacarpophalangeal pattern profile (MCPP) was determined on 34 Sotos syndrome individuals and compared with previous MCPP studies. The mean hand profile contained a major peak in the proximal phalangeal area and a smaller peak in the metacarpal area, while the distal hand bones were relatively short. There appear to be three recognized hand profiles in Sotos syndrome, which suggests heterogeneity of the syndrome, although correlation studies indicate clinical homogeneity of individuals in the younger age groups. Discriminant analysis of Sotos syndrome versus control subjects produced a function of two MCPP variables, plus age, which may be applied as another diagnostic tool.

The use of skinfold measurements to judge obesity during the early phase of Prader-Labhart-Willi syndrome

We report the first prospective longitudinal study of dietary intake, weight, height, and skinfold measurements during the early phase of four Prader-Labhart-Willi syndrome (PLWS) individuals (two males and two females). Although caloric intake ranged from 80 to 90 percent of recommended daily allowance during our study of the four PLWS infants, obesity still occurred. Our findings suggest that the onset of obesity in PLWS individuals occurs earlier than previously thought in spite of reduced caloric intake. The infants in our study reached the obese range judged by skinfold measurements greater than the 85th centile at an early age and before they were considered heavy based on weight for height criterion. We propose that skinfold measurements should be obtained on all individuals with PLWS and obesity judged by this criterion.

Two patients with ring chromosome 15 syndrome

We report on 2 patients (3 1/2 year-old-male and 6-year-old female) with the ring 15 chromosome syndrome and speech delays and review 25 cases from the literature. The main characteristics of this syndrome include growth retardation (100%), variable mental retardation (95%), microcephaly (88%), hypertelorism (46%), and triangular facies (42%). Other frequent findings include delayed bone age (75%), brachydactyly (44%), speech delay (39%), frontal bossing (36%), anomalous ears (30%), café-au-lait spots (30%), cryptorchidism (30%), and cardiac abnormalities (30%). The average age at diagnosis was 8.1 years. The average maternal and paternal age at the time of birth was 28 and 31 years, respectively.

Photoanthropometric analysis of individuals with the fragile X syndrome

A photoanthropometric method, which enables an objective description of facial structures, was used to examine 31 boys with the fragile X or Martin-Bell syndrome below the age of 12 years. The age range was 1.5 to 12 years with an average age of 6.5 years. Facial parameters were measured from strict frontal and profile photographs of fra(X) syndrome boys and compared with other facial measurements from the same face (e.g. mouth width vs. bizygomatic diameter). We studied 18 photoanthropometric facial parameters following the protocol established by Stengel-Rutkowski et al [1984]. Fourteen indices were calculated and compared with photoanthropometric index standards for age, established from normal children between 0 and 12 years [Stengel-Rutkowski et al, 1984]. Two of the fourteen craniofacial indices, broad palpebral fissures and decreased inner canthal distance, were significantly abnormal.

Steroid metabolic disturbances in Prader-Willi syndrome

We have studied steroid sulfate conjugates in serum samples from 17 children with Prader-Willi syndrome (PWS) by extraction, enzymatic hydrolysis and chromatography of the hydrolysed, free steroids. The chromatograms in patients with PWS can be divided into 2 classes. Ten (4 with the deletion on chromosome 15 and 6 without) of 17 had a normal pattern with dehydroepiandrosterone (DHEA) as the only steroid detected. However, 7 out of 17 (3 with the deletion and 4 without) had a very different pattern. The chromatogram derived from these hydrolysates had 5 major peaks. One of these was DHEA; a second peak was tentatively identified as 16 alpha-hydroxy-DHEA on the basis of column retention time and immunoreactivity. The remaining 3, more polar, compounds have not yet been identified. The presence of unusual steroid sulfoconjugates in serum may correlate with other features of PWS and may be the basis for dividing PWS into two separate disease states: a) PWS-1 associated with DHEA-S as the only sulfo-conjugate and b) PWS-2 associated with unusual sulfo-conjugates. One interesting possibility is that these sulfo-conjugates may have a hormonal function, even though no function has yet been recognized for DHEA-S. Then, PWS may be the common clinical manifestation of a variety of different defects in the sulfo-conjugate metabolic pathway.

Craniofacial variation and growth in the Prader-Labhart-Willi syndrome

A study of anthropometric variation and craniofacial growth in individuals with the Prader-Labhart-Willi syndrome (PLWS) illustrates the utility of anthropometry in clinical evaluation and research. Anthropometric measurements, including head length and breadth, minimum frontal diameter, and head circumference, were obtained on 38 PLWS individuals (21 with chromosome 15 deletions) with an age range from 2 weeks to 39 years. No anthropometric differences were found between the two chromosome subgroups. A relative deceleration in the growth of certain craniofacial dimensions (head circumference and length) is suggested by the negative correlations between age and Z-scores for the measurements. Raw values for minimum frontal diameter and head breadth were near or below the 5th percentile curve, while almost all values for head length and circumference fell within normal limits. The data support suggestions that dolichocephaly be considered an early diagnostic feature of PLWS. Furthermore, the status of narrow bifrontal diameter as a major feature of PLWS is confirmed.

Sister chromatid exchange analysis in the Prader-Labhart-Willi syndrome

The number of sister chromatid exchanges (SCE) and cell kinetics in lymphocytes were investigated from 16 Prader-Labhart-Willi syndrome (PLWS) patients [8 with 15q12 deletion (4 females, 4 males; mean age = 12.9y with age range of 0.3 to 24y), and 8 non-deletion (2 females, 6 males; means age = 16.8y with age range of 5 to 26y)], 18 parents of PLWS patients and age-matched control individuals. The average SCE frequency and standard deviation in PLWS patients with and without the chromosome 15 deletion was 6.6 +/- 1.3 and 6.2 +/- 0.8, respectively. Therefore no significant difference in SCE frequency or replicative index was found between the two PLWS subgroups. There was also no significant difference in SCE frequency or replicative index between the 16 PLWS patients and age-matched control subjects. The average SCE frequency and standard deviation in 8 fathers who were previously identified to have donated the chromosome 15 with the deletion in the child was 7.5 +/- 1.2, which was not significantly different from 8.5 +/- 2.0 seen in age-matched control subjects. There was also no significant difference in the SCE frequency or replicative index of 18 parents of PLWS patients with and without the chromosome 15 deletion when compared with age-matched control subjects.

Plasma immunoreactive beta-melanocyte stimulating hormone (lipotropin) levels in individuals with Prader-Labhart-Willi syndrome

Plasma immunoreactive beta-melanocyte-stimulating hormone (beta-MSH) levels, which actually represent the combined concentrations of beta-lipotropin (beta-LPH) and gamma-LPH in normal individuals, were measured in 12 patients (6 males and 6 females with an average age of 16.8 years, range 4 months to 27 years) with the Prader-Labhart-Willi syndrome (PLWS). Five patients were previously identified with high-resolution analysis as having the 15q chromosomal deletion, whereas 7 patients had normal chromosomes. Hypopigmentation was observed in all 5 patients with the 15q deletion. Of the 7 individuals with normal chromosomes, two were hypopigmented and 5 had normal pigmentation. Fasting (6 to 12 hours) plasma samples were analyzed for immunoreactive beta-MSH in the 12 PLWS individuals. Plasma immunoreactive beta-MSH (LPH) levels were within the normal range in all 12 individuals. There was no significant difference in the plasma immunoreactive beta-MSH concentrations between patients who did and did not have the chromosomal deletion or in those who were or were not hypopigmented. Thus, a decrease in circulating plasma immunoreactive beta-MSH (LPH) does not appear to be the cause of the hypopigmentation observed in some patients with PLWS.

Metacarpophalangeal pattern profile analysis in diastrophic dysplasia

We analyzed the metacarpophalangeal pattern profile (MCPP) on 16 individuals with diastrophic dysplasia and calculated a mean syndrome profile. Correlation studies confirm clinical homogeneity of the hand profile in diastrophic dysplasia. Discriminant analysis of individuals with diastrophic dysplasia compared with a sample of normal individuals produced a function of 3 MCPP variables plus age that appears to be a useful diagnostic tool.

Cytogenetic studies of individuals from four kindreds with multiple endocrine neoplasia type II syndrome

Multiple endocrine neoplasia type II (MEN-II) syndrome is an autosomal dominant condition characterized by medullary carcinoma of the thyroid, pheochromocytoma, and parathyroid adenoma. A cytogenetic investigation was conducted on 13 MEN-II syndrome patients from four unrelated kindreds and 13 age-matched control subjects for chromosome instability and the chromosome 20 deletion reported in MEN-II syndrome. A significant increase (p less than 0.05) was found in the total number of chromatid and chromosome aberrations in MEN-II cells (12.3%) compared with control cells (6.9%) grown at 96 hours in mitomycin C (20 ng/ml, final concentration). The major difference between the two groups was in chromatid, and not chromosome, aberrations. There was no difference between MEN-II and control individuals in fragile site expression, the number of sister chromatid exchanges or cell kinetics. A blind analysis of high-resolution G-banded chromosomes was performed on blood specimens from 13 MEN-II and seven control individuals. Twelve of 13 MEN-II patients and one of seven control subjects were scored as having a 20p12.2 deletion (chi 2 = 12.6; p less than 0.001). Additional research is needed to determine if this cytogenetic finding is due to a chromosome deletion, inversion, or polymorphism.

Renal and urinary tract abnormalities associated with chromosome aberrations

The frequency of malformations of the kidney and urinary tract is much higher in patients with chromosome aberrations than in the general population. Sixty to 100% of "cat-eye" syndrome, 60 to 80% of Turner, 75% of trisomy 8, 33 to 70% of trisomy 18, 50 to 60% of trisomy 13, and over 50% of triploidy and tetraploidy patients may have such abnormalities. Renal and urinary tract malformations should be looked for in all patients with chromosome aberrations. Moreover, a chromosome study is indicated in any fetus with an ultrasonographic evidence of urinary tract abnormality.

Rapid technique of DNA-DNA in situ hybridisation on formalin fixed tissue sections using microwave irradiation

The relative sensitivities of different protocols for detecting cytomegalovirus nucleic acid sequences in histological specimens, using a biotinylated cDNA probe, were assessed. Several commonly used pre-treatment steps were not essential, nor was the use of a highly sensitive detection system. The choice of enzyme used for proteolytic digestion of tissue seems to be important, and increasing the temperature of denaturation of tissue and probe DNA to above 100 degrees C greatly increased the sensitivity of the method. Difficulties in achieving such high temperatures in a controlled manner were overcome by the use of a rapid microwave heating method that can be used routinely in laboratories. This technique detected cytomegalovirus infections in formalin fixed, paraffin processed tissue sections within a single working day.

Demonstration of lymphoid antigens in decalcified bone marrow trephines

A panel of antibodies recognising lymphoid and epithelial antigens in formalin fixed, paraffin embedded sections was applied to a series of 54 bone marrow trephines decalcified by formic or edetic acids. Normal trephines and cases infiltrated by myeloid, lymphoid, and epithelial tumours were included. Patterns of reactivity were distinct and allowed the different diseases to be distinguished. All lymphoid tumours expressed leucocyte common antigen, with B cell tumours staining with MB1 and MB2, and T cell tumours staining with MT1 and UCHL1. T cell acute lymphoblastic leukaemia (ALL)/lymphoblastic lymphoma all stained with MT1, but some were negative with UCHL1. B cell ALL/lymphoblastic lymphoma also stained with MT1, but could be distinguished by its reactivity with MB1 and MB2. Reed-Sternberg cells did not stain with any reagent. Normal and neoplastic myeloid cells stained with MT1. Carcinomas stained with CAM 5.2 but were negative for lymphoid markers except MB2 staining in some cases. A case of neuroblastoma could be distinguished from ALL/lymphoblastic lymphoma by its lack of reactivity with all antileucocyte antibodies and its staining with antineurone specific enolase. Although not ideal, if used together, this panel of reagents may usefully be applied to routinely fixed and processed, decalcified bone marrow trephines.

Do some patients with Seckel syndrome have hematological problems and/or chromosome breakage?

We report on a 12-yr-old female and a 14-yr-old male with Seckel syndrome. The 12-yr-old female had pancytopenia, which is seen occasionally in patients with Seckel syndrome and is also a feature of Fanconi anemia, a well-recognized autosomal recessive dwarfism syndrome with chromosome instability. Chromosome breakage analysis of both of our patients also indicated chromosome instability. We suggest that there may be a subgroup of Seckel syndrome patients with chromosome instability and/or hematological problems.

Metacarpophalangeal pattern profile analysis in Robinow syndrome

We analyzed the metacarpophalangeal pattern profile (MCPP) on 15 individuals with Robinow syndrome and calculated a mean Robinow syndrome profile. Correlation studies confirm clinical homogeneity of the hand profile in the Robinow syndrome. Discriminant analysis of individuals with Robinow syndrome compared with a sample of normal individuals produces a function of 6 MCPP variable that may provide a useful tool for diagnosis.

A 26-month-old child with Marden-Walker syndrome and pyloric stenosis

We recently examined a 26-month-old boy with abnormal face, blepharophimosis, hypertelorism, apparently low-set ears, micrognathia, arachnodactyly, talipes equinovarus, and joint contractures. Subsequently he manifested failure to thrive, respiratory infections, and developmental delay. These congenital anomalies and associated findings are consistent with a diagnosis of the Marden-Walker syndrome. He also had mild pyloric stenosis and duodenal bands, not previously reported in this syndrome. This syndrome appears to be an autosomal recessive trait in some families. A summary of findings of the 16 previous published patients is presented.

Metaphase chromosome folds and X-inactivation

To evaluate the suggested nonrandom folding of Xq13-q21 (center of Barr body condensation) of the inactivated X chromosomes, metaphases from nine subjects with or without X chromosome abnormalities (eight females and one male) were investigated with RBG-staining. A significant increase (p less than .05) in the number of arm folds (Xq13-q21) of the late-replicating X chromosome, particularly in early to mid-metaphase, was observed in four of eight females. Therefore, the stage of chromosome contraction was an important factor with more folds observed at the centromeres and in longer chromosomes in early metaphase compared with mid- to late metaphase. X chromosome folds were present in cells of subjects treated with or without bromodeoxyuridine. While our study agrees with the relationship of Xq13-q21 fold with the X-inactivation center, the correlation of extended chromosomes and folding limits this method as a sole indicator of X-inactivation in routine mid-metaphase, but is useful in the analysis of early metaphase chromosomes.

An anthropometric study of 38 individuals with Prader-Labhart-Willi syndrome

Weight, height, sitting height, and 24 other anthropometric variables (5 body circumferences, skinfolds at 7 sites, 4 head dimensions, and 8 hand and foot measurements) were obtained on 38 Prader-Labhart-Willi syndrome (PLWS) individuals (21 with apparent chromosome 15 deletions and 17 nondeletion cases) with an age range of 2 weeks to 38 1/2 years. More than half of these individuals were measured on more than one occasion. The measurements confirmed the presence of short stature, small hands and feet, obesity, and narrow bi-frontal diameter in PLWS. No differences were found for the anthropometric measurements between the 2 chromosome subgroups. Inverse correlations were produced with linear measurements (eg, height, hand and foot lengths) and age, which indicated a deceleration of linear growth relative to normal individuals with increasing age.

Robinow syndrome: report of two patients and review of literature

We report two patients with Robinow or fetal face syndrome. We present a thirteen year follow-up on three previously published cases and a review of 32 cases in the literature. The cardinal features of this condition include mesomelic shortening of the forearms, frontal bossing, hypertelorism, wide palpebral fissures, short upturned broad nose with anteverted nares, long philtrum, small chin, brachydactyly, hypoplastic genitalia and a normal karyotype. Development delay and mental retardation was noted in 18% of the reported cases. Early death was identified in about 10% of the cases. Genetic heterogeneity is suggested with autosomal dominant inheritance reported in 8 individuals from 3 families and autosomal recessive inheritance in 8 siblings from 4 families although no clinical differences were identified among those individuals with different inheritance patterns. Male to male transmission was reported in one family. Parental age does not appear to be a factor in the cause of this syndrome.

New marker of B lymphocytes, MB2: comparison with other lymphocyte subset markers active in conventionally processed tissue sections

The use of the murine monoclonal antibody MB2 for identifying B lymphocytes in routinely processed tissue was evaluated and contrasted with the use of the monoclonal antibody UCHL1 for identifying T cells. One hundred and sixty eight surgical biopsy specimens were immunostained with these antibodies, including a wide range of normal and neoplastic non-lymphoid tissues, as well as normal lymphoreticular tissues and lymphomas. Sixty four non-Hodgkin's lymphomas were also examined, of which 51 had been previously phenotypically defined. In selected cases the results were compared with those obtained using two other monoclonal antibodies MB1 and MT1, used for identifying B and T cells, respectively, in paraffin sections. MB1 stained a smaller proportion of B cell tumours than MB2 and staining was, in general, weaker, except in one case of centroblastic lymphoma. MT1 immunoreactivity was comparable with that of UCHL1, except in one case of T lymphoblastic lymphoma (MT1 positive, UCHL1 negative). None of the antibodies is ideal, but, if used as a panel, they permit the separation of B cells and T cells in paraffin sections.

High resolution chromosome and DNA analysis in multiple endocrine neoplasia type II syndrome

Multiple endocrine neoplasia type II (MEN-II or Sipple's syndrome) is an autosomal dominant disorder characterized by medullary thyroid cancers, pheochromocytomas, and parathyroid adenomas. A blind analysis of high resolution G-banded chromosomes was performed on blood specimens from eight MEN-II individuals from three unrelated families and six control subjects. Seven of eight MEN-II patients and one of six control subjects were determined to have a deletion at 20p12.2. These findings support the hypothesis that MEN-II patients have a 20p12.2 deletion (chi 2 = 6.99; p less than 0.01). Genomic DNA from seven of the eight MEN-II patients was studied using the DNA probe, D20S5, localized by in situ hybridization to 20p12. The probe binding site is not deleted in some MEN-II patients, as demonstrated by the presence of two alleles detected as restriction fragment length polymorphisms. Thus, D20S5 does not hybridize to DNA sequences that are deleted based on cytogenetic analysis in MEN-II patients.

Acetone/periodate-lysine-paraformaldehyde (PLP) fixation and improved morphology of cryostat sections for immunohistochemistry

Cryostat sections are extensively used in the study of lymphoid tissues because the majority of antigens do not survive routine fixation and processing. A major disadvantage of cryostat section immunohistochemistry is their poor morphology. The use of periodate-lysine-paraformaldehyde (PLP) fixation regimes for cryostat sections was evaluated and compared with conventional acetone immersion. This fixation gives excellent morphology but poor immunostaining. The quality of immunostaining with a panel of 31 antibodies was good with brief acetone fixation followed by PLP fixation. Morphological preservation was very good. We suggest that acetone-PLP fixation is an improvement over acetone alone for cryostat section immunohistochemistry.

Cytokeratin and laminin immunostaining in the diagnosis of cutaneous neuro-endocrine (Merkel cell) tumours

Nine cutaneous neuro-endocrine tumours have been immunostained with monoclonal antibodies to low molecular weight cytokeratin (CAM 5.2) and neurofilament. Polyclonal antisera to neurone-specific enolase, calcitonin and laminin were also used. All nine cases showed paranuclear, dot-like positive staining with CAM 5.2 and diffuse cytoplasmic staining for neurone-specific enolase. Neurofilament and calcitonin immunoreactivity could not be demonstrated. All tumours were negative for laminin immunoreactivity. The limitations of staining for neurone-specific enolase are discussed and the value of CAM 5.2 in the differential diagnosis of cutaneous neuro-endocrine tumours is emphasized. The histogenetic implications of the absence of laminin staining are considered.

Isolated atrial amyloid contains atrial natriuretic peptide: a report of six cases

Twenty five specimens of the human right atrial appendage were examined for immunoreactivity to alpha human atrial natriuretic peptide. In the electron microscope characteristic amyloid fibrils were identified around small blood vessels and adjacent to atrial muscle cells in eight of the surgical cases and in two necropsy cases. In six cases, four surgical and two necropsy, these fibrils contained immunoreactive alpha human atrial natriuretic peptide. Amyloid is known to occur in peptide secreting endocrine tumours and immunoreactive peptide may be incorporated in the amyloid matrix. The demonstration of atrial amyloid containing immunoreactive alpha human atrial natriuretic peptide suggests that some deposits of cardiac amyloid are of a type analogous to that found in other endocrine organs.

Metacarpophalangeal pattern profile analysis in clinical genetics: an applied anthropometric method

The hand is a complex anatomical structure with the component bones susceptible to a combination of environmental and genetic factors that may affect the bone length and width. The alterations may involve a single bone or specific group of bones. The metacarpophalangeal pattern profile (MCPP) developed by Poznanski, Garn, and others (Poznanski et al. Birth Defects VIII (5): 125-131, 1972) is a graphic representation of the relative lengthening and shortening of the 19 tubular bones of the hand useful for diagnosis, comparison of dissimilar patients, and gene carrier detection. The profile hand bone measurements are derived from posteroanterior hand radiographs and are standardized for age and sex. Specific profiles have been developed for several syndromes. Therefore, MCPP analysis has developed from a method of describing changes in the hand to a technique useful in assigning a diagnosis to a specific syndrome and evaluation of skeletal development. The current status of MCPP analysis in clinical genetics, particularly with the Prader-Labhart-Willi and Sotos syndromes, is discussed.