The variable phenotype in tetrasomy 18p syndrome. A propos of a subtle dysmorphic case.

The variable phenotype in tetrasomy 18p syndrome. Apropos of a subtle dysmorphic case: Tetrasomy 18 is a rare chromosomal syndrome. Its frequency is 1/40,000 newborns and more than 40 cases have been reported. In this paper we report a 25-month-old female patient referred for chromosome examination essentially because of delayed psychomotor development. The physical examination showed: microcephaly, mild generalized spasticity, arched eyebrows, horizontal palpebral fissures with unilateral convergent strabismus, bilateral epicanthic folds, small nose, well placed ears, oral cavity with high arched palate and upper vestibular frenula, tented mouth with slightly everted upper lip, hands with normal palmar creases and long fingers. All the blood tests were normal, while the magnetic resonance imaging reported mild demyelination and polymicrogyria. The karyotype was 47,XX,+i(18)(p10).ish i(18)(plO)(D18Z1+) de novo.

Benign familial macrocephaly in a mother-son pair.

Macrocephaly can be found isolated or associated with other anomalies as a part of specific syndrome. Benign Familial Macrocephaly (BFM) is a primary macrocephaly and autosomal dominant and multifactorial inheritances had been proposed. Cole and Hughes (5), described clinically seven patients. We report two BFM cases, a boy and his mother. The male propositus showed macrocephaly with dolicocephaly shape, frontal bossing, narrowing biparietal and a square-shaped face. Neurological examination was normal. He had two computed tomography (CT) scans of the skull, one at 7 months of age showing extracerebral fluid collection in the anterior convexity and increased interhemispheric subarachnoid space and a second normal CT scan at 3 years of age. The mother showed macrocephaly with dolycocephaly shape and dished-out mid-face. This family exhibited the full clinical spectrum of BFM, with an autosomal dominant inheritance.

Interstitial 1q42-q44 deletion defined by FISH in a short-lived female.

We report a female newborn with a de novo 1q4 deletion ascertained by G bands but refined as an interstitial one by FISH with a subtelomeric 1q probe; hence, the final karyotype was 46,XX,del(1)(q42q44).ish subtel1q x 2. She presented a few typical features of the del(1q42) syndrome. Additionally, she showed occipital skin aplasia, interauricular communication, and intestinal perforation-obstruction and she died at 24 days of age. This observation illustrates the clinical variability of the syndrome as well as the occasional reduced survival. The redefinition by molecular cytogenetics of a terminal deletion as an interstitial one suggests that interstitial deletions are more common than reported by classic cytogenetics and can partially account for the phenotypic variability in some deletion syndromes.

Schilbach-Rott syndrome in a third family: further delineation of an autosomal dominant trait.

We describe a father-son Mexican pair with typical features of Schilbach-Rott syndrome (SRS): ocular hypotelorism, cleft palate, hypospadias (only in the child), and microcephaly. This observation documents for the first time a male to male transmission and therefore confirms that the SRS is inherited as an autosomal dominant trait with variable expressivity.

Zimmermann-Laband syndrome: further clinical delineation.

Zimmermann-Laband syndrome (ZLS) is an autosomal dominant disorder characterized by gingival fibromatosis, absent or dysplastic distal phalanges, vertebral defects, hepatosplenomegaly, hypertrichosis and sometimes mental retardation. We describe two unrelated patients, a girl aged 9 years and a boy 11 months whose clinical and radiological findings permit us to diagnose the ZLS. Body overgrowth, present in both patients, was identified as a main clinical feature not previously reported as well as the presence in neuroimaging studies of a cavernous hemangioma on the frontal and the left cerebellar regions in the boy. The girl also presented important radiological characteristics such as broad medulary canals and metaphyses of long bones, thin cortices, broad ribs, accelerated skeletal maturation as well as high intelligence level. A wide clinical spectrum in ZLS is also considered.

Guadalajara camptodactyly type III: a new probably autosomal dominant syndrome.

A Mexican family is presented with the main clinical features of camptodactyly, a distinctive facial appearance because of ocular hypertelorism, telecanthus, symblepharon and spinal defects. Other clinical manifestations included: multiple nevi, simplified ears, retrognathia, congenital shortness of the sternocleidomastoid muscle, thin hands and feet, a small penis and mild mental retardation. Radiographic studies revealed spina bifida occulta at cervical and dorso-lumbar levels, increased bone trabeculae, cortical thickening and delayed bone age. The presence of five affected members through four generations suggests autosomal dominant inheritance although no male-to-male transmission was documented. The authors propose this as a new entity, and have designated it Guadalajara camptodactyly type III.

[Gestational diabetes mellitus and congenital malformations]. / Diabetes mellitus gestacional y malformaciones congénitas.

INTRODUCTION: Maternal diabetes mellitus affects approximately 5% of all pregnancies. Pregestational diabetes mellitus has been associated with a high risk of spontaneous abortions and congenital malformations during the first trimester of pregnancy then is considered teratogenic. This frequency of birth defects is three to fivefold increased compared with general population. Although an association of gestational diabetes mellitus (GDM) with an increase of congenital malformations has not been demonstrated, some clinical and epidemiological studies of this possible association have reported the presence of GDM in mothers of children with congenital malformations. THE OBJECTIVE: Of this study was to compare the prevalence of congenital malformations associated with GDM in relation to pregestational diabetes mellitus and general population. MATERIALS AND METHODS: In the present study 3 groups were compared: the group I was integrated by 112 new born of mothers with GDM; in the group 2, there were 30 new born from women with gestational diabetes mellitus. 103 new born from healthy women integrated the group 3. All patients were recruited consecutively during a period of 18 months. RESULTS: A total of 24 cases with congenital malformations were detected. The group with the higher prevalence was the group 2 (30%). We found a tendency to a higher risk of congenital malformations on the cases exposed to GDM (group 1) compared with the group not exposed (group 3). The analysis of the mothers background of the children from group 2 with congenital malformations showed a significant difference in the antecedent of previous macrosomic product in comparison with the antecedents of the mothers of the same group that bear healthy babies. COMMENT: The results of the analysis in the studied population did not show an association between GDM and congenital malformations, although there is a tendency to a higher prevalence in comparison with not exposed population. This could be due to the heterogeneity of the GDM; an entity usually detected late in pregnancy, but probably present since the first weeks of gestation when the teratogenic effect could occur. CONCLUSION: In the present study we found that the antecedent of previous macrosomic products is an important risk factor, therefore, such women require a close vigilance of the glucose levels before and during the first weeks of pregnancy in order to prevent congenital malformations, one of the principal causes of death in the new born.

Two different Philadelphia chromosomes in a cell line from an AML-M0 patient.

A second Philadelphia (Ph) chromosome is one of the most common nonrandom secondary chromosome changes in leukemias with 9;22 translocations. It has been suggested, and observed in two studies of masked t(9;22), that the second Ph chromosome is an exact duplication of the entire derivative chromosome 22. In a cytogenetic study of bone marrow cells from an acute myelogenous leukemia patient, a cell line carrying two different Ph chromosomes evidenced by a chromosome 22 centromeric heteromorphism was found. From this observation arose the question whether the second der(22) was a true Ph chromosome or whether it was a deleted chromosome derived from the normal chromosome 22 that did not contain the bcr-abl rearrangement. A fluorescent in situ hybridization (FISH) study with the t(9;22) probe revealed two bcr-abl positive signals on 60 of 100 interphase nuclei. The second Ph could have resulted from a mitotic crossing over; or, analogously to late-appearing Philadelphia chromosomes, it may be derived from a new chromatid translocation between the chromosomes 9 and 22 not involved in the initial t(9;22).

Silver-Russell syndrome and exclusion of uniparental disomy.

Recently, maternal uniparental disomy for the entire chromosome 7 was described in three of 25 Silver-Russell syndrome sporadic cases, yet the etiology of the remaining cases is unclear. Two cases with Silver-Russell syndrome and a balanced translocation involving the 17q25 had been reported. We looked for evidence of genomic imprinting due to uniparental disomy 17 in seven patients with sporadic Silver-Russell syndrome and their parents. Additionally, chromosomes 7, 8, 11 and 20 were studied. Uniparental disomy was ruled out for all these chromosomes in six of seven families; one family was informative only for chromosome 17. Not-withstanding our negative results, it is still possible that uniparental disomy plays a part in this syndrome. A mutation in a Mendelian gene in 17q25 could also account for the Silver-Russell syndrome etiology.

Alphoidless centromere of a familial unstable inverted Y chromosome.

We report on a 3-generation pedigree in which an inverted unstable Y chromosome had no phenotypical or reproductive repercussion despite a sizable proportion of secondary aneuploidies (mainly 45, X cells) in lymphocytes. This chromosome was metacentric and had a single Cd-positive primary constriction, but occasionally assumed a normal acrocentric aspect. FISH using the probe DYZ3 revealed a single strong signal; unexpectedly, the signal was outside the primary constriction and appeared to map in the middle of p, that is, at the usual centromeric localisation. Therefore, this chromosome should be regarded as a remarkable pseudodicentric because the major alphoid array was located at the inactive centromere but not at the active one. This chromosome may have resulted from a) a transcentric inversion with the 48 bp satellite array of proximal Yq being relocated next to the Yq heterochromatin, or b) an intrachromosomal insertion of nonalphoid centromeric sequences.

Floating-Harbor syndrome. A neuropsychological approach.

We describe a six year old Mexican girl whose clinical picture (short stature with delayed bone age, language difficulties and triangular face with prominent nose) was compatible with the diagnosis of Floating-Harbor Syndrome (FHS). A neuropsychological evaluation disclosed a mild mental retardation, a constructive apraxia, a comprehensive and expressive language impairment. The analysis of the present case and sixteen patients previously described establishes that the FHS is mainly characterized by proportionate short stature with significantly delayed bone age, delayed expressive language and peculiar face.

Molecular characterization of the fragile-X syndrome in the Mexican population.

The fragile X (fra-X) syndrome is the most frequent form of inherited mental retardation. Facial dysmorphism, macroorchidism and a folate-sensitive fragile site on Xq27.3 are commonly associated features. The gene causing this disorder, designated as FMR1, is X-linked and shows an unusual inheritance mode. A multistep amplification of the CGG repeats at the 5' end of the FMR1 gene has been recently identified as the cause of the fra-X syndrome. Different numbers of repeats define three gene forms (normal, premutated and mutated), whose ranges show little variation in the populations studied so far. We analyzed 18 Mexican individuals with the fra-X syndrome, 40 of their relatives (first and second degree), and 76 healthy individuals without antecedents of mental retardation. Southern blot and PCR permitted the assessment of the number of CGG repeats and the methylation state of the FMR1 gene for the normal, premutated, and mutated alleles. The results showed no statistical differences when compared with those from other populations. No cytogenetic expression of the Xq27.3 fragile site in 50% of the affected males and in all the affected and carrier females was observed. This finding emphasizes the necessity of a molecular analysis in fra-X cases and their relatives in order to provide a more adequate genetic counseling.

Spondyloepimetaphyseal dysplasia (SEMD) Shohat type.

Recently a distinct spondyloepimetaphyseal dysplasia (SEMD) was reported in three members of a Jewish family. We present a 3.5-year-old Mexican boy with disproportionate short stature, peculiar face, short neck, small chest, abdominal distension, lumbar lordosis, short limbs, marked genua vara, and joint laxity. Roentgenologic findings include short long bones, wide and flared metaphyses with irregularities, delayed epiphyseal ossification, platyspondyly and morphological changes of vertebral bodies and fibular overgrowth. The striking resemblance of this patient to those previously reported confirms this form of SEMD as a distinct entity. Autosomal recessive inheritance is supported and the designation SEMD Shohat type is proposed.

The Myhre syndrome: report of two cases.

Two unrelated patients, aged 19 and 6 years, were studied and diagnosed as having Myhre syndrome (MS). This review, together with three previous cases, permits further delineation of MS. The main features are: short stature, mental retardation, blepharophimosis, muscular hypertrophy, decreased joint mobility, thick calvarium, broad ribs, hypoplastic iliac wings and short tubular bones. Advanced paternal age at the propositi's birth suggests an autosomal dominant mutation as the cause of MS.

Kaufman oculocerebrofacial syndrome: report of two new cases and further delineation.

Two unrelated Mexican girls, aged 14 months and 6 years respectively, with Kaufman oculocerebrofacial syndrome, are reported. Both showed psychomotor retardation, microcephaly, blepharophimosis and delayed growth as the main features; the infant also presented preauricular tags and large clitoris. Comparative analysis with previous cases reveals a heterogeneous syndrome in which the micro-brachycephaly, the mongoloid slanted eyes with different anomalies, the micrognathia and the neonatal respiratory distress are the most typical characteristics of this mental retardation syndrome.

Guadalajara camptodactyly syndrome type I. A corroborative family.

Three sibs, two girls aged 18 and 9 years, and a 7-year-old boy, were found to have Guadalajara camptodactyly syndrome type I (GCSI). They had intrauterine growth retardation, dwarfism, peculiar facial appearance, camptodactyly and skeletal anomalies. Comparison with other camptodactyly syndromes led to the conclusion that the patients had the same disorder as the two first reported patients with GCSI. The clinical and radiological concordance in the five patients permits further delineation of GCSI and corroboration of its autosomal recessive inheritance.