Whole gene duplication of SCN2A and SCN3A is associated with neonatal seizures and a normal intellectual development.

Duplications at 2q24.3 encompassing the voltage-gated sodium channel gene cluster are associated with early onset epilepsy. All cases described in the literature have presented in addition with different degrees of intellectual disability, and have involved neighbouring genes in addition to the sodium channel gene cluster. Here, we report eight new cases with overlapping duplications at 2q24 ranging from 0.05 to 7.63 Mb in size. Taken together with the previously reported cases, our study suggests that having an extra copy of SCN2A has an effect on epilepsy pathogenesis, causing benign familial infantile seizures which eventually disappear at the age of 1-2 years. However, the number of copies of SCN2A does not appear to have an effect on cognitive outcome.

A neocentric isochromosome Yp present as additional small supernumerary marker chromosome--evidence against U-type exchange mechanism?

Here we report the first case of an inverted duplicated neocentric small supernumerary marker chromosome present in a karyotype 47,XX,+mar(Y). As expected a partial disomy of Ypter to Yp11.2 did not lead to any major malformations. However, the formation of an inverted duplicated chromosome from a Y chromosome is not possible by a U-type exchange, as has been suggested for such kind of neocentric marker chromosomes. Thus, some evidence is here provided that this concept might not always be true.

The gene for autosomal dominant hidrotic ectodermal dysplasia (Clouston syndrome) in a large Indian family maps to the 13q11-q12.1 pericentromeric region.

Hidrotic ectodermal dysplasia (HED), Clouston syndrome (MIM No. 129500), is an autosomal dominant disorder affecting the skin and its derivatives. It is characterized by alopecia, dysplastic nails in hands and feet, and hyperkeratosis of the palms and soles. We have studied a large Indian pedigree (UR005), from Gujarat region, consisting of a total 127 individuals including 41 affected (12 males and 29 females). The phenotype in this family ranged from atrichosis to hypotrichosis, sparsity or absence of eyebrows, and thickening of palms and soles. In order to map the disease locus by linkage analysis, DNA polymorphisms were used in DNAs from 23 affected and 8 normal individuals. While genotyping was in progress, Kibar et al. [1996] reported mapping of the locus of a similar disease in French-Canadian families to 13q around marker D13S141. We then utilized markers on 13q to genotype the members of the Indian family. Linkage with 13q11-12.1 markers was confirmed with a maximum lod score of 3.27 (theta=0.00) with locus D13S1316. Multipoint linkage analysis yielded a lod score of 5.04 at theta=0.00 with D13S1316; haplotype analysis indicated that the gene for the Clouston syndrome in this family is localized proximal to D13S292. These data suggest that the gene for the Clouston syndrome in this Indian pedigree is probably the same as that described in the French Canadian families. The combination of data from all available families linked to 13q11-12.1 will make it possible to narrow the critical region and facilitate the positional cloning of the elusive gene.

Three siblings with Harlequin Ichthyosis in an Indian family.

The Harlequin fetus is a distinct genetic entity with a strikingly grotesque appearance. Three siblings (two males, one female) with Harlequin Ichthyosis, a rare form of congenital disorder, born to the same parents are presented. The genetic aspects are discussed and the relevant literature is reviewed.

A newer avenue for evaluation of thyroid dysfunction.

Attempt has been made to rationalise the biochemical assessment of patients suspected to have thyroid dysfunction by introduction of a new rapid and supersensitive immunoradiometric assay (IRMA) for TSH. 294 patients were subjected to thyroid investigation viz; tT3, tT4 and TSH (IRMA). Of these, 51 (17.34%) were hypothyroid, 22 (7.48%) were hyperthyroid and 221 (75.1%) were euthyroid. The ratio of thyroid disorder in male to female was 1:3.38. In all patients with hyperthyroidism TSH (IRMA) was 0.05 to undetectable and it was more than 4.5 ulu/ml in hypothyroid patients. TSH (IRMA) was low in one euthyroid patient a 0.34% incidence of false negativity. In 2 patients with subclinical hyperthyroidism TSH (IRMA) was low while tT3 and tT4 were normal. TSH (IRMA) therefore may obviate the need for more time consuming and expensive TRH test and simplify the approach to thyroid function tests in patients suspected to have masked or overt hyperthyroidism.

Study of anticardiolipin antibodies in repeated abortions--an institutional experience.

A cohort of 178 pregnant women with a history of first or second trimester abortions (2 or more) were the base of present study. In all, other causes of abortion were ruled out except for anti-phospholipid syndrome. Anti-Cardiolipin antibody (ACA) (IgG & IgM) was estimated in the sera samples of all women. Out of 178 women, any one or both immunoglobulins were above the cut off range (> 15.0 units) in 47 (26.4%) while both immunoglobulins were normal in 131 (73.59%) women. Both immunoglobulins were present in only 0.5% women. ACA-IgG alone was present in 11.79% while ACA-IgM alone was present in 14.04% women. We observe from present study that ACA is a major cause of recurrent fetal loss & many pregnancies can be saved if diagnosed & treated adequately.

Genotype-Phenotype Characterization of Wolf-Hirschhorn Syndrome Confirmed by FISH: Case Reports.

The Wolf-Hirschhorn syndrome (WHS) is a multiple malformation and contiguous gene syndrome resulting from the deletion encompassing a 4p16.3 region. A microscopically visible terminal deletion on chromosome 4p (4p16→pter) was detected in Case 1 with full blown features of WHS. The second case which had an interstitial microdeletion encompassing WHSC 1 and WHSC 2 genes at 4p16.3 presented with less striking clinical features of WHS and had an apparently "normal" karyotype. The severity of the clinical presentation was as a result of haploinsufficiency and interaction with surrounding genes as well as mutations in modifier genes located outside the WHSCR regions. The study emphasized that an individual with a strong clinical suspicion of chromosomal abnormality and a normal conventional cytogenetic study should be further investigated using molecular cytogenetic techniques such as fluorescence in situ hybridization (FISH) or array-comparative genomic hybridization (a-CGH).

Diagnostic strategy for mucolipidosis II/III.

Overlapping clinical phenotypes are a diagnostic challenge to the clinician, especially in the cases of mucolipidosis (ML) and mucopolysaccharide disorders (MPS), due to overlapping phenotypes. Present study was carried out in 147 children suspected to have ML or MPS and 100 controls. They were screened for ML II/III by colorimetric method using substrate pNCS. Six children were found screen positive for ML II/III and further confirmatory study showed significantly raised activity in plasma confirming high specificity of the ML screening test. Forty-two (28.5%) children out of remaining 141 children that were screen negative, were found to have various MPS disorders, while rest 99 had normal enzyme activity in plasma and leucocytes. Present study demonstrates prompt and specific chemical method that can be used as a tool for estimating ML II/III, with high specificity.

Beta-thalassemia mutations in western India.

OBJECTIVE: To study occurrence of common mutations in the population of Gujarat and the most prevalent mutation in certain high-risk communities. METHODS: The mutation screening was carried out using ARMS-PCR in children with beta thalassemia. RESULTS: Population screening has identified certain communities like Sindhis, Lohana, Rajputs, and SC/ST/OBC to be at higher risk as compared to others. The most common mutation was IVS 1-5 (G-->C) followed by 619 bp deletions of the total cases coming to Gujarat. CONCLUSION: Molecular evaluation for Thalassemia should be considered for families whose ethnicity indicates origin from high-risk community.

Translocation t(22;22)(p11.1;q11.1) and NOR studies in a female with a history of repeated fetal loss.

A 32-year-old phenotypic female with a history of nine consecutive abortions each in the first trimester was referred for cytogenetic studies. She was found to have 45,XX,t(22;22) (p11.1;q11.1) chromosomal pattern. The Ag-NOR banding technique showed that the NORs of both the acrocentrics involved in the translocation were deleted and the loss suffered from the elimination was compensated by the increased NOR activity as well as presence of dNOR on other acrocentric chromosomes.

A triple-X female with long arm deletion of one of the X-chromosomes associated with primary amenorrhoea: 47,XX, +del(X) (q27.3).

A 25-year-old phenotypic female with primary amenorrhoea was referred for chromosomal analysis. Earlier she had undergone hormonal therapy but showed no response. The secondary sex characters were of female type, with poor breast development. Laparoscopic findings revealed the presence of a very small uterus; the right ovary was found to be undeveloped and the left was absent. Cytogenetic study revealed a case of triple-X with deletion of the terminal region of the long arm of one of the X chromosomes [Xq27.3]. Among the 100 buccal mucosa cells analysed, 30 cells showed double Barr bodies. Hormonal studies using RIA technique revealed normal levels of prolactin (9.1 ng/ml), a high level of FSH and LH (135 and 61 mIU/ml) and low levels of estradiol and progesterone (12 pg/ml and 0.20 ng/ml respectively). To our knowledge, this may be the first report of a triple X with deletion of the X chromosome associated with primary amenorrhoea.

Incomplete gonadal dysgenesis.

A 21-year-old phenotypic male with ambiguous external genitalia and hypospadias was referred for cytogenetic studies. Exploratory laparotomy revealed presence of a small atropic uterus, unilateral gonadal dysgenesis with fallopian tubes on both sides and a cryptorchid testis on the left side. No gonad could be traced on the right side. Chromosomal analysis from peripheral whole blood culture revealed a 46,XY cell line. No mosaicism was detected. Endocrine studies showed elevated levels of serum FSH and LH with low borderline testosterone level and failure to respond to HCG stimulation. The presence of fallopian tube next to testis suggests absence of anti-Mullerian hormone secretion by Sertoli cells. The absence of Wolffian duct derivatives indicates insufficient secretion of testosterone by Leydig cells.