Multiple congenital defects associated with trisomy for the short arm of chromosome 4

Clinical manifestations of trisomy 4p syndrome

Trisomy 4p syndrome is a distinct clinical entity which was noted almost a quarter century ago by Wilson et al. [71] and later was delineated by Gonzalez and colleagues [29]. The variation in the length of duplicated segment usually associated with monosomy of other genetic material which has resulted in confusion and as a result a so-called 4p syndrome could not be recognized without cytogenetic analysis. We wish to draw the attention of clinicians to this subject by presenting the description of over 75 cases including one from our clinic and stress the point that molecular approaches are imperative to characterize this anomaly. After extensive review, it appears that patients retaining at least the distal two-thirds to the entire short arm share an overlapping phenotypic expression that constitutes pure trisomy 4p syndrome which includes prominent glabella, bulbous nose with flat or depressed nasal bridge, retrognathia, pointed chin, short neck with low hairline, enlarged ears with abnormal helix and antihelix, rocker-bottom feet with prominent heel. Arachnodactyly and camptodactyly. Molecular characterization of 4p is imperative. We have also included an extensive bibliography for clinicians who may find it useful as a single reference source for evaluating their future cases.

CONCLUSION

The 4p-syndrome is a distinct entity but without cytogenetic evaluation, the syndrome can not be recognized.

Familial Wolf's syndrome with a hidden 4p deletion by translocation of an 8p segment. Unbalanced inheritance from a maternal translocation (4;8)(p15.3;p22). Case report, review and risk estimates

This is the case report of a patient with Wolf's syndrome having a monosomy 4pter----p15.3 and an additional trisomy 8pter----p22, derived from a maternal balanced translocation t(4;8)(p15.3;p22) after 2:2 disjunction and adjacent-1 segregation. The patient's phenotype is presumably slightly modified by the trisomic 8p segment. Literature analyses indicate that phenotypic "hybrids" with traits of monosomy 4p and of other autosomal segment trisomies exist. The dermatoglyphics of the patient were not highly characteristic for Wolf's syndrome. Also the dermatoglyphics of the balanced translocation carriers were unspecific and did not reflect the carrier status. Pedigree analyses of 46 reported families with reciprocal translocations involving the short arm of chromosome 4 show a high risk (20.5% +/- 4.6%) for unbalanced offspring (trisomy or monosomy 4p) after 2:2 disjunction and adjacent-1 segregation, if the breakpoint in the recipient chromosome is terminal and the resulting imbalance concerns the 4p segment only. It is considerably lower (4.5% +/- 2.5%) if the breakpoint in the recipient chromosome is subterminal, as in the reported case, and the resulting imbalance concerns other chromosome segments additionally to the 4p segment. In both instances, the risk decreases with increasing segment length. The risk for unidentified abortions, stillbirths or neonatal deaths is also high in these families (about 40%). The frequency of progeny with balanced compared to progeny with normal karyotype corresponds to the expected 50% for alternate segregation.

Factors predisposing to adjacent 2 and 3:1 disjunctions: study of 161 human reciprocal translocations

Reciprocal translocations produce imbalances by three types of disjunction which are, in decreasing frequency, adjacent 1, 3:1, and adjacent 2. Adjacent 1 disjunction produces duplication deficiencies of inverse topography to those of adjacent 2. The imbalanced chromosome segments in one of these types are balanced in the other. The disjunction 3:1 produces pure trisomies and monosomies. The following situations predispose to adjacent 2 disjunction: translocations between the long arms of two acrocentric chromosomes or between one of these and that of a No 9 chromosome; centric segments, either short or carrying a heterochromatic zone (9qh); a balanced translocation in the mother. The factors predisposing to the disjunction adjacent 2 operate by selection, or directly on the meiotic configuration. Some of them (shortness of the interstitial segment, shortness of the short arms of translocation chromosomes) act in both these ways. Their influence is probably responsible for the repetitive and exclusive character of this disjunction. The conditions for the occurrence of the 3:1 disjunctions seem less strict than those for adjacent 2, although they should be of the same nature (involvement of acrocentrics or a chromosome 9 in the translocation, maternal origin).

4p trisomy syndrome: report of 4 additional cases and segregation analysis of 21 families with different translocations

Thirty reports of partial 4p trisomy have been published. The manifestations and cytogenetic findings in four additional cases from two families are described in the present paper. Segregation analysis has been performed on the 21 families reported to date. The risk of having unbalanced offspring was the same in carrier mothers and carrier fathers. The risk of trisomic offspring was 14%. Among phenotypically normal progeny, normal karyotypes and balanced translocation states occurred with about equal frequency.

Trisomy 4p: five new observations and overview

Five new cases of trisomy of the short arm of chromosome No. 4 are presented. In two brothers the abnormality arose from segregation of the 4p chromosome present in the mother who is a carrier of a centric fission of one No. 4 chromosome. In the other three patients, the chromosome imbalance originated from segregation of a balanced maternal 3p/4q or 4/22 translocation. The available data, derived from the 4p trisomics reported so far, are adequate to establish trisomy of the short arm of chromosome No. 4 as a definite clinical entity. The most outstanding findings include growth retardation of prenatal onset, severe mental deficiency, microcephaly and a peculiar constellation of facial dysmorphisms. The dermatoglyphic patterns and the radiological findings may help towards a correct interpretation of the syndrome.

'Complete 5p' trisomy: 1 case and 19 translocation carriers in 6 generations

A description is given of a female infant with multiple malformations and mental retardation who died at 31 months. Cytogenetic studies indicate trisomy of the complete short arm of chromosome 5, resulting from the unbalanced segregation of a balanced translocation in the mother whose karyotype was interpreted as 46,XX,t(5; 15)(p11; p12). The karyotype of the proband was designated 46,XX, der(5)t(5; 15)(p11; p12)mat. Family studies indicate that the translocation has been present in the family for at least 6 generations.

The trisomy 4p syndrome: case report and review

We report a further case of trisomy 4p: a 5-year-old mentally retarded boy with characteristic facial features, eye abnormalities, flexion contractures, several bone anomalies, and hyperactivity. In a review of 27 cases (11 male, 16 female, 22 families) the cytogenetic and clinical data were tabulated and analyzed. Diagnosis is established by karyotype: there is always partial or apparently "total" trisomy of the short term arm of chromosome 4. In 19 families a parent carried either a balanced translocation (16 times) or a pericentric inversion (3 times); 3 patients had de novo duplication of 4p. In several cases, additional deletions or trisomies were present. From the analysis of all cases, but particularly of the "pure" trisomies, the phenotypic spectrum of this condition was observed and found to be a specific multiple congenital anomaly/mental retardation (MCA/MR) syndrome. Its main features are a characteristic facial appearance, postnatal growth retardation, severe psychomotor retardation with or without seizures, microcephaly, and various major and minor anomalies.

Hand dermatoglyphics in trisomy 4p

A dermatoglyphic analysis of the hands of 16 patients with trisomy for the short arm of chromosome 4 has revealed an increased frequency of whorl patterns on fingertips, presence of axial triradii in position t' on palms and an increase of the main line index. Although of little diagnostic value these changes must be included in the constellation of major signs which characterize the 4p trisomy syndrome.

[Trisomy 4p. Three new observations (author's transl)]

Three new observations of trisomy 4p are reported. Two are due to a maternal translocation t(4;15). The third is due to a "mirror" duplication, it is the first case of trisomy 4p without balanced parental rearrangement. The very characteristic phenotype is compared to that of 13 other patients already reported in the literature.

Trisomy 4p14 leads to 4pter with translocation t(4;15)(p14;p12) in the father

A trisomy 4p14 leads to 4pter in a 15-year-old girl is reported. The main features are physical and mental retardation and the absence of gross malformations. The relevance of other symptoms found in the patient is discussed.