Natural course of subclinical hypothyroidism in Down's syndrome: prospective study results and therapeutic considerations.

Pathogenesis, natural course and therapeutic management of subclinical hypothyroidism (SH) in Down's syndrome (DS) remain object of debate in literature. In the present study thyroid function, antithyroid antibody (ATA) prevalence and serum lipid concentrations were investigated in a group of 344 Down patients (DP) and data were compared with those obtained from a control group of 257 age and sex matched healthy subjects. Thyroid function and ATA prevalence were also studied in 120 parents of DP. SH prevalence was clearly higher in DP (32.5% of cases) than in controls (1.1%) and parents (0%). Similarly, ATA prevalence was higher in DP (18% of cases) than in controls (5.8%) and parents (6.6%). In spite of this, no correlation was found in DP between SH and ATA prevalences, since ATA were detected in 18.7% of SH-DP and in 15.8% of euthyroid DP. Thus, circulating ATA were not detected in the majority of SH-DP. No significant differences regarding T4, FT4, T3 and serum lipid levels among SH and euthyroid DP and controls were found. Moreover, TSH levels were only slightly increased, generally less than 10 microU/ml, in most cases of SH-DP. Follow-up was longer than 24 months (range 2-7 years, mean 3.1) in a group of 201 DP: two different patterns of SH course were observed, mainly depending on the presence or the absence of circulating ATA. In particular, 35.7% of ATA-positive SH-DP developed a clinically evident thyroid disease (overt hypothyroidism or hyperthyroidism), while no similar case was recorded among ATA-negative SH-DP.(ABSTRACT TRUNCATED AT 250 WORDS)

Electroclinical diagnosis of Angelman syndrome: a study of 7 cases.

The authors describe 7 new cases of Angelman syndrome (AS: 3 males and 4 females) diagnosed on the basis of clinical features (dysmorphic facial features, severe mental retardation with absent speech, peculiar jerky movements, ataxic gait and paroxysms of inappropriate laughter) and neurophysiological findings. Failure to detect deletion of the long arm of chromosome 15 or the absence of epileptic seizure were not considered sufficient to exclude a diagnosis of AS. Feeding problems, developmental delay and early signs of ataxia, especially tremor on handling objects and unstable posture when seated, proved effective as clinical markers for early diagnosis of AS. The EEG patterns characteristic of AS were found within the first 2 years of life (under 18 months in the majority of cases). The authors conclude that AS should be included in differential diagnosis in a child aged under 12 months having cryptogenic psychomotor retardation with prevalent language compromise. Repeat EEG recordings are needed to check for the typical trace, and cytogenetic investigations are mandatory.

Uniparental disomy explains the occurrence of the Angelman or Prader-Willi syndrome in patients with an additional small inv dup(15) chromosome.

A patient with Angelman syndrome and a 46,XY/47,XY,+inv dup(15)(pter-->q11: q11-->pter) karyotype and a patient with Prader-Willi syndrome and a 46,XY/47,XY,+inv dup(15)(pter-->q12: q12-->pter) karyotype were investigated with molecular markers along chromosome 15. Paternal uniparental isodisomy was found for all informative markers in the first case which indicates that this, rather than the presence of the extra chromosome, is the cause of the Angelman syndrome phenotype. Similarly, the PWS patient showed maternal uniparental distomy with absence of PWS region material on the inv dup(15) chromosome. If (1) marker chromosomes are an occasional by product of 'rescuing' a trisomic fertilisation, or (2) if duplication of the normal homologue in a zygote which has inherited a marker in place of the normal corresponding chromosome 'rescues' an aneuploid fertilisation, or (3) if the presence or formation of a marker chromosome increases the probability of non-disjunction, then uniparental disomy might be found occasionally in other subjects with de novo marker chromosomes.

Hypomelanosis of Ito: involvement of chromosome aberrations in this syndrome.

The authors report on cytogenetic results of six patients with hypomelanosis of Ito. Karyotypes from peripheral lymphocytes prometaphases and skin fibroblasts metaphases were normal. A review of the literature revealed no specific chromosomal abnormality but a close association between mosaicism and HI syndrome. The X-chromosome was involved in 53% of the abnormal cases.

Spontaneous resolution of cystic hygroma in a 46,XX normal female.

We report a case of nuchal cystic hygroma with spontaneous resolution detected by ultrasound examination at 13 weeks' gestation. Fetal karyotype and amniotic fluid alpha-fetoprotein levels were normal. Extreme caution in evaluating this situation is stressed.

Observations on the visual-perceptual abilities and adaptive behavior in adults with Down syndrome.

In this research, we consider some psychological, social, and clinical implications of premature aging in persons with Down syndrome (DS). Perceptual and adaptive tests contribute to a better knowledge of the characteristics of mental decline and self-government in DS adults. Visual-perceptual abilities (as measured by the Frosting Development Test of Visual Perception) and behavioral and social adaptation (measured by the Brown Adaptive Behavioral Inventory) were examined in 44 DS subjects aged 14 to 43 years. The results indicated a general decline in performance in the older groups (over 25 years), except in the visual-motor subtest, where a decline is less evident, as this ability continues to be exercised in craft work. Statistical analysis indicates a significant correlation between perceptual abilities, adaptive scales, and mental age. From the data collected, we draw some general conclusions about the trend of perceptual abilities and self-government in relation to aging in DS persons.

Thyroid function in patients with Down syndrome: preliminary results from non-institutionalized patients in the Veneto region.

We investigated thyroid function of 108 home-reared Down syndrome (DS) patients. Five had overt hypothyroidism, 2 were hyperthyroid, and 33 had high TSH values with an exaggerated response to TRH test despite hormone levels in the normal range. This finding indicated subclinical hypothyroidism. Antithyroid antibodies (antimicrosome and antithyroglobulin) were present in 13 patients. At the same time we investigated 73 parents: only one mother was hypothyroid and antithyroid autoantibodies were found in only 8% of Down syndrome parents.

Down syndrome in the Belluno district (Veneto region, northeast Italy): age distribution and morbidity.

A structured pre-planned form was used to collect data on age distribution and morbidity of Down Syndrome (DS). Survival rates are also reported. The incidence of autoimmune disease among DS individuals was higher than in the normal population. Alopecia (7%), atopic dermatitis (35%), and autoimmune thyroiditis were the most frequently reported conditions, but diabetes and ulcerative colitis were also observed.

Duplication of an Xp segment that includes the ZFX locus causes sex inversion in man.

Two 46,XY females with tandem duplications of an X short arm segment were studied by cytogenetic and Southern blot analysis. The results show that the duplicated segment in each case included the Xp21.2-Xp22.2 interval, resulting in a double dose of ZFX on the single active X chromosome. The results from our two cases, in conjunction with those reported by other workers, lead us to conclude that the duplication is the reason for the sex inversion. If ZFY and ZFX are indeed sex-determining gene loci, these findings favour a model of sex determination characterized by antagonistic interaction between these genes.

A new family with extra material on proximal 15q.

Proximal extra material in the long arm of chromosome 15, has been described in individuals with different phenotypes (isolated mental retardation, multiple malformations, repeated miscarriages), and with apparently normal phenotype, in which cytogenetic analysis was invariably carried out on the basis of clinical indications. The paper describes a child with mental retardation, and his father, who both had proximal extra material in 15q. Caution is advised in the study of karyotype-phenotype correlation.

Terminal deletion of the short arm of chromosome 5.

Three cases of deletion of the short arm of chromosome 5 are described: one family cluster, in which the mother and three sons are affected, and two sporadics without the typical "cri du chat" phenotype (the family and Case 2 were previously reported in 1982). Mental retardation varied between affected members of the same family. Band p15.2 appears critical for the development of the complete phenotype. A peculiar deafness observed in the familial and one of the sporadic cases suggests a cochlear malformation.

Trisomy 8p by malsegregation of a t(5;8)(p15;p11)mat in a case of XY pure gonadal dysgenesis.

A new case of trisomy 8p due to balanced t(5;8)(p15;p11)mat in a phenotypically female infant with a male karyotype is reported; postmortem examination disclosed streak gonads.

Partial duplication of 17 long arm.

Three subjects from 2 unrelated families with partial duplication of 17q, derived from a reciprocal parental translocation between chromosomes 11 and 17 with different breakpoints, are described. A female patient from one family with a 46,XX,-11,+der(11),t(11;17)(q24;q23.2)pat chromosome complement had died at 2 months of age. In the second family, a male propositus and a subsequent fetus, identified by cytogenetic prenatal diagnosis, showed a 46,XY,-11,+der(11),t(11;17)(q2505,q24.3) mat chromosome complement. Twelve other cases involving partial duplication of chromosome 17 have been reported, 11 of these derived from a balanced translocation, and 1 was a duplication. All these cases showed psychomotor and mental retardation, cranial contour anomalies, micrognathia, bulbous nose, short neck, skeletal anomalies, and CNS defects. The phenotypic and clinical observations in the three subjects of this report are compared with previously reported findings.

Frequency of abnormal karyotypes in relation to the ascertainment method in females referred for suspected sex chromosome abnormality.

Cytogenetic investigation was carried out on 231 female patients referred for suspected sex chromosome abnormality. Cases were classified into five groups according to reason for referral and chromosome abnormality frequency was estimated. The overall frequency of abnormal karyotypes was 38.5%. The rate of positive identification of chromosome abnormality ranges from 0 in patients with secondary amenorrhoea to 80% in those with Turner phenotype. Our data demonstrate that the indications for referral of female patients with suspected sex chromosome abnormality are not only primary amenorrhoea alone or short stature and primary amenorrhoea without Turner stigmata, but also short stature of unknown etiology without any additional anomaly during childhood.

Ring chromosome 21 in phenotypically apparently normal persons: report of two families from Switzerland and Italy.

If a ring 21, originating from breaks close to the telomere of 21q and anywhere in 21p, replaces a normal 21, it may be associated with an apparently normal phenotype. An apparently normal mother and son were ascertained by a prenatal chromosome study. A second mother, with a ring 21 but without gross anomalies, is short of stature, has epilepsy and has a low normal intelligence. He daughter is a mosaic: 46,XX/47,XX,+r(21) and has the Down's syndrome. None of these four persons was found to have mitoses with more than one ring 21 or with rings of double size.

Replication patterns of human X isochromosomes by high-resolution banding.

The DNA replication patterns of eight cases of X isochromosomes, five idic(X) and three i(Xq), were studied. R-banded prometaphases and metaphases from lymphocyte cultures after synchronization with methotrexate and incorporation of 5-bromodeoxyuridine were analyzed. No significant differences in the frequency of metaphases with symmetric and asymmetric replication patterns between dicentric and monocentric isochromosomes were found. Furthermore the distribution of the frequencies of R-positive bands was similar and comparable to that of the normal late-replicating X. Our data suggest that the DNA replication pattern of Xq isochromosomes is not correlated with the mechanism of their origin.