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A case of prenatally diagnosed true mosaicism for trisomy 5 with a clinically normal outcome is presented. Trisomy 5 was detected in 23% of cells obtained by amniocentesis, but it was not detected from cells obtained by fetal blood sampling. While in this case the finding at amniocentesis did not reflect the status of the fetus, care must be exercised in reaching this conclusion in all cases.

The previously unreported and unique finding of a complete disomy of an apparently balanced reciprocal translocation is described. The parents are second cousins once removed and each parent contributed the same balanced reciprocal translocation chromosome. Although the complete disomy involves balanced translocation chromosomes from unaffected parents, it is possible that a hemizygous state of some genes may be present on each translocation chromosome, which in a disomic homozygous state could result in an abnormal phenotype, as manifested by infantile seizures in this patient.

We report on a patient with multiple congenital anomalies and ring chromosome 22 who died at age 16 years of bronchopneumonia. Autopsy documented multiple psammomatous meningiomas of the spinal dura and tentorium. Tumor tissue for cytogenetic analysis was not available. Although abnormalities of chromosome 22 in tumor tissue have been reported, to our knowledge, this is only the third report of a constitutional chromosome 22 abnormality associated with the development of meningiomas. Thus, a constitutional chromosome 22 abnormality may predispose to the development of meningiomas.

We report on a male with Kallmann syndrome (KS) and an apparently balanced complex chromosome rearrangement (CCR): 46,XY,t(3; 9)(9;12)(q13.2;q21.2p13;q15). This is the first known report of a CCR in the KS and the second reported case of a definitive autosomal chromosome abnormality with KS. Possible relationships between the cytogenetic abnormality and KS are discussed.

A case of Prader-Willi syndrome is presented in which high resolution chromosome analysis revealed not only a familial Robertsonian translocation [t(13q15q)], but also a del(15) (q11.2q13) of the chromosome 15 not involved in the translocation. While there have been numerous reports of Robertsonian translocations involving chromosome 15 in patients with Prader-Willi syndrome, in this case, the Robertsonian translocation was shown to be unrelated to the clinical findings.

In order to assess the impact of the increasing awareness of the fra(X) syndrome and a broader approach to fra(X) testing, we analyzed our laboratory experience for 1980-1988. In 1981–1986, there was an avearage of 80 cases/year (62 male; 18 female). The 103 (74 male; 29 female) cases in 1987 represent a 45% increase over the prior 3 years; this sustained in 1988 with 106 cases. The fra(X) positive yield decreased from a high of 49% in 1980 to an average of 20% (range 15–24%) in 1981–1984, 10% (range 9–11%), in 1985–1987 and 7% in 1988. The positive rate for males and females was nearly identical in both time periods. The positive yield for mentally retaded individuals with a family history of mental retardation dropped from an average of 20% for 1981–1984 and 33% for 1985–87 to 13% for 1988; hopwever, the positive fra(X) rate for mentally retarded individuals decreased from an average of 23% in 1981–1984 to 9% in 1985–1987 and 7% in 1988. The decreasing fra(X) yield and increasing case load are directly attributable to the relaxation of criteria for referral and testing related to the referral of all mentally retarded patients, and to the perceived malpractice liability for not doing a “complete” evaluation. Although the burden for cytogenetic laboratories is considerable, the yield of positive fra(X) cases is still worthwhile, and may be maximized by the use of improved screening criteria.

Deletion of 16q is characterized by mental retardation, microcephaly, a characteristic combination of minor facial anomalies, and broad halluces. Various break points have been described. This patient's phenotype is typical of this syndrome, but in addition, unusual radiographic findings were present. This chromosome abnormality is compatible with survival into adulthood. Expression of this phenotype does not appear to be correlated with specific break points.

The Smith-Lemli-Opitz syndrome (SLOS) and the Meckel syndrome (MS) have been regarded as separate autosomal recessive entities. Recently, overlap of these two syndromes has been discussed. A sibship containing a probable new syndrome with features reminiscent of the SLOS and the MS is presented. The literature is reviewed with regard to the frequency of various malformations in these syndromes. Clinical manifestations and cerebellar abnormalities in these sibs are similar to those described in the Joubert syndrome (JS). These three cases may represent a new syndrome with features in common with SLOS, MS, and JS resulting from the same mutant gene, which exhibits considerable pleiotropy.

The wrinkly skin syndrome is an autosomal recessive disorder characterized by wrinkling of the skin of the dorsum of the hands and feet, decreased elastic recoil of the skin, an increased number of palmar and plantar creases, multiple musculoskeletal abnormalities, microcephaly, and mental retardation. Our patient is characteristic of the syndrome as previously described, and confirms the presence of mental retardation and microcephaly as component manifestations, with the additional findings of connective tissue abnormalities evidenced by an atrial septal aneurysm.

A human pregnancy exposed to TC-83 live attenuated Venezuelan equine encephalitis (VEE) virus vaccine resulted in hydrops fetalis and fetal demise. Maternal seroconversion and the finding of a diffuse mononuclear cell infiltrate on postmortem examination are suggestive of a causative role for TC-83 vaccine.

Spondylocostal dysostosis, anal atresia, and urogenital anomalies were observed in two male infants of a consanguineous Mennonite couple. A careful review of previously reported syndromes of severe vertebral abnormalities and/or imperforate anus suggests that our patients have a previously undescribed recessive disorder that should be included in the differential diagnosis of rib and vertebral anomaly syndromes.

The acrocallosal syndrome (ACS) is a probable autosomal recessive condition of macrocephaly, craniofacial and hand and foot abnormalities, absence of the corpus callosum, and mental retardation. This patient had characteristics of the ACS but also had a severe congenital heart defect and other visceral malformations. After comparing the ACS with and contrasting it to other disorders, we concluded that the internal organ abnormalities found in this patient probably represent further manifestations of the ACS.