P. S. N. Menon

Screening of families with autosomal recessive non-syndromic hearing impairment (ARNSHI) for mutations in GJB2 gene: Indian scenario

Several studies have reported that mutations in the GJB2 gene (coding for connexin26) are a common cause of recessive non‐syndromic hearing impairment. A GJB2 mutant allele, 35delG, has been found to have a high prevalence in most ethnic groups. Though mutations in the GJB2 gene have been shown to cause autosomal recessive deafness in Indian families, the frequencies of the various mutations are still unknown. In the present study, we analyzed 45 Indian families belonging to three different states, namely, Karnataka, Tamil Nadu, and Delhi with non‐syndromic hearing impairment and an apparently autosomal recessive mode of inheritance. All the families were initially screened for three mutations (W24X, W77X, and Q124X) by using allele‐specific PCR primers; mutations were confirmed by DNA sequencing. Families that were heterozygous or negative for tested mutations of the GJB2 gene were sequenced directly to identify the complementary mutation and other mutations in GJB2. Four families were homozygous for W24X, constituting around 8.8%. In two families, the affected individuals were compound heterozygotes for W24X; one family (DKB16) carried 35delG with W24X while the other family (DKB7) carried R143W with W24X. We suggest that W24X is a common allele among the mutations screened, causing autosomal recessive non‐syndromic hearing impairment (ARNSHI) in the Indian population.

Growth Hormone Therapy

Growth hormone (GH) therapy has revolutionized treatment of children with growth hormone deficiency (GHD). Improved height outcome with final height in the target height range has been achieved in these children. Identification of Creutzfeldt-Jakob disease, a deadly prion mediated disorder, in recipients of pituitary GH accelerated the transition from pituitary derived GH to recombinant GH. Once daily subcutaneous administration of the freeze-dried preparation at evening is the recommended mode of GH therapy. Studies have led to use of higher dose of GH for improving height outcome (0.33 mg/kg/week or 0.14 IU/kg/day) albeit at a significantly high cost. Growth velocity increases from 3–4 cm/year before therapy to 10–12 cm/year during the first two years of therapy and is maintained at 7–8 cm/year after a period of two years. Close follow-up with regular clinical and laboratory monitoring is essential for achieving a desirable height outcome. A theoretical unlimited supply has led to wide spread use of GH in a variety of disorders other than GHD. Initially started in children with Turner syndrome, GH has now been used in chronic renal failure, idiopathic short stature and intrauterine growth restriction besides a wide array of newly emerging indications.

Ovarian Cysts in Young Girls with Hypothyroidism: Follow-up and Effect of Treatment

Ovarian cysts have been reported in girls with longstanding uncompensated primary hypothyroidism. Restoration of euthyroid state has been associated with resolution of these cysts; long-term follow-up of these patients is however lacking. We evaluated the outcome in ten girls with ovarian cysts and hypothyroidism managed at our hospital with special emphasis on subsequent pubertal development and ovarian imaging. Patients were diagnosed at the age of 8.6 +/- 2.3 years (mean +/- SD) with severe uncompensated primary hypothyroidism (TSH levels >100 mIU/l in all; 509.3 +/- 651 mIU/l) and growth retardation (height SDS -4.1 +/- 1.8). Nine girls had vaginal bleeding at diagnosis; five also had thelarche. LH and FSH levels were prepubertal in all patients. Ovarian cysts were bilateral in eight girls (80%); internal septation was noted in six. Thyroxine replacement (4.1 +/- 0.7 microg/kg/day) led to normalization of TSH levels with reversal of pubertal changes and regression of ovarian cysts in all patients 2.2 +/- 1.0 months after treatment. At last follow-up 3.5 +/- 2.6 years after initiation of treatment at the age of 12.0 +/- 2.3 years, all patients had normal ovarian size in ultrasound evaluation with six girls progressing to normal puberty. Our study emphasizes the need to exclude hypothyroidism in young girls with ovarian cysts. Identification of hypothyroidism in these girls obviates the need for extensive investigations.

Prenatal diagnosis in hemophilia A using factor VIII gene polymorphism—Indian experience

The heterogeneous nature of the mutations, the size, and the complexity of the factor VIII gene makes direct mutation analysis in hemophilia A families in India an option that is not very feasible and practical. Thus, carrier screening and prenatal diagnosis of hemophilia A often depends on haplotype analysis using restriction fragment length polymorphisms (RFLP) and short tandem repeat (STR) markers to track the defective factor VIII gene within a family. The main objective of this present study was to assess the utility of using polymerase chain reaction (PCR)-based five polymorphic markers: four intragenic Hind III, Bcl I, intron 13, and intron 22 STRs and one extragenic marker St14 in prenatal diagnosis. Forty-one chorionic villus samples (CVS) were studied from 41 families with a history of hemophilia A. PCR and RFLP were used for screening. Intron 22 STR showed the highest informativeness (60.9%), followed by Hind III (51.2%), Bcl I (46.3%), & intron 13 STR (51.2%); the extragenic marker St14 (VNTR) was informative in 46.3% of families. Linkage analysis, with the combined use of these five PCR-based polymorphic markers, gives good informativeness of 87.8% in the Indian population. Of the 41 CVS tested, 21 were found to be male fetuses and of these 13 were found likely to be affected with hemophilia A. Only in 12.2% of the families were none of the markers informative.

Insulin like growth factors axis and growth disorders.

The growth hormone-insulin like growth factor (GH-IGF) axis plays a crucial role in the regulation of growth. Initially considered to be a mediator of growth hormone actions, IGF axis has been established as an independent endocrine system with wide array of actions. Recent advances have led to tremendous increase in the clinical utility of the IGF axis. IGF-based investigations (IGF1 and IGF binding protein 3) are now replacing GH-based investigations for evaluation and monitoring of disorders of the GH-IGF axis. IGF therapy has been successfully utilized in growth hormone insensitivity syndrome and GHD type 1B. The possibility of IGF axis as therapeutic options is being explored in wide variety of disorders like hypoxic-ischemic encephalopathy, Alzheimers disease and psoriasis.

Hypothalamic hamartoma, gelastic epilepsy, precocious puberty – a diffuse cerebral dysgenesis

Childhood epileptic syndrome characterized by early onset gelastic seizures, hypothalamic hamartoma and precocious puberty is well recognized though rare. We report association of agenesis of corpus callosum, Dandy-Walker complex and heterotopic gray matter with this childhood epileptic syndrome which is hitherto an unreported association. The child showed a satisfactory response to gonadotropin releasing hormone agonist.

Fraser-cryptophthalmos syndrome.

Fraser or Cryptophthalmos syndrome is a variable syndrome to the extent that cryptophthalmos might not be present in all cases. However, the main features are a “hidden eye”, other craniofacial abnormalities, renal abnormalities, syndactyly and abnormal genitalia. It may be classified as isolated cryptophthalmos or cryptophthalmos sequence and cryptophthalmos syndrome. The cryptophthalmos syndrome has an autosomal recessive mode of inheritance. Isolated cryptophthalmos has been reported as an autosomal dominant trait. Prenatal diagnosis is possible using ultrasonography and fetoscopy. We report three cases of cryptophthalmos. One with renal agenesis had cryptophthalmos syndrome and the other two had isolated cryptophthalmos or cryptophthalmos sequence.

Infantile-onset leukoencephalopathy with discrepant mild clinical course

Four children characterised by megalencephaly and cerebral leukoencephalopathy with infantile onset, defined on the basis of clinical and neuroimaging findings are reported. The course of the disease is characterised by stabilization of the macrocephaly and slow clinical deterioration. The CT scan findings include supratentorial diffuse hypodensities in the white matter and swelling. The characteristic MRI findings include the discrepant severity in comparison with the clinical picture, diffuse supratentorial white matter abnormalities with subcortical cysts. The basic defect of the disease is unknown. Considering the high rate of consanguinity among the parents and the presence of two affected sibs in one family, an autosomal recessive inheritance is assumed. We report four unrelated cases of this entity.

Insulin analogues and management of diabetes mellitus

The introduction of insulin analogues, of which insulin lispro is the prototype, marks a very important milestone in the management of patients with diabetes mellitus. It differs from regular human insulin in its quicker onset and shorter duration of action. Invarious clinical trials, insulin lispro was found to be superior to regular human insulin in controlling postprandial hyperglycemia without increasing the risk of hypoglycemia. It improved the quality of life of diabetic patients by providing more flexibility to meal plans. Recently, another short acting insulin analogue called insulin aspart has been tried in clinical studies with benefits similar to insulin lispro. The turn of the millennium is now witnessing the development of long acting insulin analogues like insulin glargine, which can provide continuous low-level basal insulin concentrations similar to natural settings. In this review, we discuss the potential of insulin analogues in the modern management of diabetes with emphasis on insulin lispro.

Physical Growth in Children with Reflux Nephropathy with Normal or Mildly Impaired Renal Function

Ten children aged 11 months to 10 years (means 5.7 years) with reflux nephropathy, vesicoureteric reflux (VUR) and normal or mildly impaired renal function having GFR more than 50 ml/min/1.72 m2, were included in the study. The hematological and biochemical parameters were within normal limits. Height standard deviation score (HZ score) was reduced at entry and, decreased further during follow-up (−2.2 and −2.6 at 0 and 12 months, respectively). Weight for height index (WHI) improved significantly (p=0.0004) during follow-up. The basal and stimulated peak growth hormone levels of these patients were found to be elevated, 18.53 ± 11.36 μg/L and 34.20 ± 5.86 μg/L, respectively. The IGF-1 levels were low ranging from 45.00 to 84.40 ng/dl (mean ± SD 61.54 ± 10.21 ng/dl) compared to 51.80 to 247.50 ng/dl (mean ± SD111.20 ± 70.24 ng/dl) in age and sex matched controls, indicating partial insensitivity to growth hormone.