Fra(X) frequency on the active X-chromosome and phenotype in heterozygous carriers of the fra(X) form of mental retardation

Female heterozygotes of the fra(X) form of mental retardation show variable degrees of mental impairment and phenotype expression of the disorder. This might be an effect of inactivation of the X-chromosome which carries the fra(X)(q). Prior replication studies in heterozygous carriers gave contradictory results with respect to possible genotype-phenotype correlation. In the interpretation of these studies it is important to understand the effect of BrdU on the fra(X)(q) expression. In a group of 13 hemizygous patients with fra(X)(q) and 7 heterozygous carriers we studied the effect of BrdU on fra(X) expression. In the heterozygous carriers the use of BrdU resulted in a significant suppression of the fra(X)(q), while in hemizygous patients no difference in fra(X)(q) frequency with or without BrdU could be observed. It can be concluded that BrdU suppresses the fra(X)(q) preferentially on the inactive X-chromosome. Thus the fra(X)(q) frequency on the active X-chromosome is of primary importance in phenotype correlation studies among heterozygous carriers. In our group of heterozygous carriers we observed a negative correlation between (IQ) phenotype and fra(X)(q) expression on the active X-chromosome. This suggests that the gene for the fra(X)(q) form of mental retardation is on the X-chromosome and undergoes inactivation.     

An unusual bandlike web in an infant with lethal multiple pterygium syndrome

We report on a patient with a lethal multiple pterygium syndrome who also had an unusual, bandlike web across one axilla and partial intestinal atresia. Umbilical cord wrapping with subsequent vascular compromise appears to be the most likely pathogenetic mechanism for the additional anomalies.     

First trimester diagnosis of Rho (D) with an immunofluorescence technique after chorionic villus sampling

Double indirect immunofluorescence technique (DIIF) was applied to fetal erythrocytes from vascularized chorionic villi, obtained by chorionic villus sampling (CVS) in the first trimester of pregnancy, to determine the presence of Rhesus antigen Rh (D).     

Dermatoglyphic peculiarities in families with X-linked mental retardation and fragile site Xq27: a collaborative study

The dermatoglyphic patterns of fingertips, palms and soles of 75 male patients with X-linked mental retardation and fra-Xq27 and of 28 obligate female heterozygotes were analyzed and compared with the data from 200 male and 200 female control individuals. The results show that there is a strong association between the fra-X-syndrome and dermatoglyphic peculiarities observed in male patients and also in female heterozygotes. The characteristic dermatoglyphic features of the fra-X-syndrome are: increased frequencies of radial loops, whorls and arches on the fingertips, a pronounced transversal course of palmar ridges, lower a-b RC, absence of c-triradii on the palms, abnormal palmar and plantar creases, dysplasia of the papillary ridges and low frequencies of true patterns on the soles. Some of these patterns were found in the female carriers of fra-Xq27 also. The combination of palmar and plantar patterns, expressed by a "log. score-Index", provides a high degree of discrimination between the male patients with fra-X-syndrome and the control group. A preliminary log. score-Index was developed also for the female heterozygotes. A "phantom picture" of the dermatoglyphic stigmata is constructed. We suggest that dermatoglyphic examination of the members of families suspected for fra-Xq27-syndrome can be useful for predicting this state and for diagnosing male hemizygotes and carrier females.     

Guidelines for the preparation and analysis of the fragile X chromosome in lymphocytes

The following guidelines were adopted by an Ad Hoc Committee convened at the Fourth International Workshop on the Fragile X Syndrome and X-Linked Mental Retardation to establish minimum cytogenetic standards for the preparation and analysis of the fragile X chromosome. The intention of the committee was to develop and provide practical standards for the routine cytogenetic detection of the fragile X. The guidelines describe reasonable criteria for effective tissue culture methods for eliciting the Xq27.3 fragile site in vitro and for the analysis of such chromosome preparations.     

Isochromosome 18q with karyotype 46, XX, i(18q). Cytogenetics and pathology

Cytogenetic and morphological findings of a 20-gestational-week-old female fetus with karyotype 46,XX,i(18q) are reported. The fetus displayed clinical features resembling Edward's syndrome. No characteristic symptoms of monosomy 18p could be observed.     

Caudal dysplasia and femoral hypoplasia-unusual facies syndrome: different manifestations of the same disorder?

The Caudal Dysplasia syndrome and the Femoral Hypoplasia-Unusual Facies syndrome have been reported to be more frequent among infants of diabetic mothers. We report a newborn girl who presented with features compatible with both syndromes. The possibility that both conditions represent different manifestations of the same disorder is discussed.Abbreviations IDM's Infant of diabetic mother syndrome - FHUFS Femoral Hypoplasia-Unusual Facies syndrome     

Knee pterygium syndrome in a newborn infant

We report on a newborn boy with popliteal pterygium syndrome. Congenital anomalies included popliteal pterygia, symblepharon, cleft lip and palate with syngnathia, severe hypoplasia of both thumbs, a characteristic nail anomaly of both first toes, multiple syndactylies, and a hypoplastic scrotum with cryptorchidism. Mental development can be expected to be normal. Overall prognosis of the disorder after detailed operative correction is apparently favorable. Differential diagnosis is discussed in detail. The syndrome is autosomal dominantly inherited, our patient represents an isolated case.     

Mental retardation, acromegalic face, and megalotestes in two half-brothers: a specific form of X-linked mental retardation without fra(X) (q)?

We describe a family with two half-brothers affected with severe mental retardation. The phenotype in the affected individuals is characterized by apparent acromegaly, profound mental retardation, and hyperactivity. The mother has analogous but less severe facial anomalies and mild mental impairment. Screening for fra(X) (q) was negative in peripheral lymphocytes using methotrexate for fra(X) enhancement. The clinical findings in our patients are similar to those described by Fryns et al. [1986] in two patients with acquired lesions of the central nervous system. CT investigations in one of our patients showed areas of hyperdensity in the pontine region and a small subarachnoid cyst. The pedigree suggests X-linked inheritance. The association of apparent acromegaly, CNS anomalies, megalotestes, and mental retardation in this family supports the hypothesis that a distinct syndrome may exist with phenotype anomalies more severe than those characteristic for the Martin-Bell syndrome but without fragile X.