Jamal Raza

SNX10 mutations define a subgroup of human autosomal recessive osteopetrosis with variable clinical severity.

Human Autosomal Recessive Osteopetrosis (ARO) is a genetically heterogeneous disorder caused by reduced bone resorption by osteoclasts. In 2000, we found that mutations in the TCIRG1 gene encoding for a subunit of the proton pump (V‐ATPase) are responsible for more than one‐half of ARO cases. Since then, five additional genes have been demonstrated to be involved in the pathogenesis of the disease, leaving approximately 25% of cases that could not be associated with a genotype. Very recently, a mutation in the sorting nexin 10 (SNX10) gene, whose product is suggested to interact with the proton pump, has been found in 3 consanguineous families of Palestinian origin, thus adding a new candidate gene in patients not previously classified. Here we report the identification of 9 novel mutations in this gene in 14 ARO patients from 12 unrelated families of different geographic origin. Interestingly, we define the molecular defect in three cases of “Västerbottenian osteopetrosis,” named for the Swedish Province where a higher incidence of the disease has been reported. In our cohort of more than 310 patients from all over the world, SNX10‐dependent ARO constitutes 4% of the cases, with a frequency comparable to the receptor activator of NF‐κB ligand (RANKL), receptor activator of NF‐κB (RANK) and osteopetrosis‐associated transmembrane protein 1 (OSTM1)‐dependent subsets. Although the clinical presentation is relatively variable in severity, bone seems to be the only affected tissue and the defect can be almost completely rescued by hematopoietic stem cell transplantation (HSCT). These results confirm the involvement of the SNX10 gene in human ARO and identify a new subset with a relatively favorable prognosis as compared to TCIRG1‐dependent cases. Further analyses will help to better understand the role of SNX10 in osteoclast physiology and verify whether this protein might be considered a new target for selective antiresorptive therapies.

Exome sequencing identifies CTSK mutations in patients originally diagnosed as intermediate osteopetrosis

Autosomal Recessive Osteopetrosis is a genetic disorder characterized by increased bone density due to lack of resorption by the osteoclasts. Genetic studies have widely unraveled the molecular basis of the most severe forms, while cases of intermediate severity are more difficult to characterize, probably because of a large heterogeneity. Here, we describe the use of exome sequencing in the molecular diagnosis of 2 siblings initially thought to be affected by “intermediate osteopetrosis”, which identified a homozygous mutation in the CTSK gene. Prompted by this finding, we tested by Sanger sequencing 25 additional patients addressed to us for recessive osteopetrosis and found CTSK mutations in 4 of them. In retrospect, their clinical and radiographic features were found to be compatible with, but not typical for, Pycnodysostosis. We sought to identify modifier genes that might have played a role in the clinical manifestation of the disease in these patients, but our results were not informative. In conclusion, we underline the difficulties of differential diagnosis in some patients whose clinical appearance does not fit the classical malignant or benign picture and recommend that CTSK gene be included in the molecular diagnosis of high bone density conditions.

Precocious Puberty in Children

OBJECTIVE To determine the etiology of precocious puberty in children and to compare the clinical and laboratory parameters of central and peripheral precocious puberty. STUDY DESIGN Cross-sectional study. PLACE AND DURATION OF STUDY Endocrine Clinic at National Institute of Child Health, Karachi, from January 2009 to December 2011. METHODOLOGY Children presenting with precocious puberty were included. The age of onset of puberty was documented. Clinical evaluation, Tanner staging, height, height SDS, weight, weight SDS, body mass index, bone age, pelvic USG, plasma estradiol level and GnRH stimulation were done. Ultrasound of adrenal glands, serum level of 17 hydroxyprogesterone, ACTH, Renin, aldosterone and testosterone were performed in children with peripheral precocious puberty. MRI of adrenal glands and gonads was done in patients with suspected tumor of that organ and MRI of brain was done in patients with central precocious puberty. Skeletal survey was done in patients with Mc Cune-Albright syndrome. RESULTS CAH (81.8%) indentified as a main cause in peripheral percocious puberty and idiopathic (67.74%) in central precocious puberty. Eighty five patients were registered during this period. The conditions causing precocious puberty were central precocious puberty (36.47%), peripheral precocious puberty (38.82%), premature pubarche (10.58%) and premature thelarche (14.11%). There was a difference in the age of onset of puberty in case of central precocious puberty (mean=3, 2-6 years) versus peripheral precocious puberty (mean=5.25; 3.62 - 7.0 years). Children with central precocious puberty showed higher height SDS, weight SDS, FSH, LH than those with peripheral precocious puberty. CONCLUSION Etiology in majority of cases with peripheral precocious puberty was congenital adrenal hyperplasia and idiopathic in central precocious puberty. Central precocious puberty children showed higher height SDS, weight SDS, FSH, LH than peripheral precocious puberty.

Etiological Diagnosis of Undervirilized Male / XY Disorder of Sex Development

OBJECTIVE To do clinical, hormonal and chromosomal analysis in undervirilized male / XY disorder of sex development and to make presumptive etiological diagnosis according to the new Disorder of Sex Development (DSD) classification system. STUDY DESIGN Case series. PLACE AND DURATION OF STUDY Endocrine Unit at National Institute of Child Health, Karachi, Pakistan, from January 2007 to December 2012. METHODOLOGY Patients of suspected XY DSD / undervirilized male visiting endocrine clinic were enrolled in the study. Criteria suggested XY DSD include overt genital ambiguity, apparent female/male genitalia with inguinal/labial mass, apparent male genitalia with unilateral or bilateral non-palpable testes, micropenis and isolated hypospadias or with undescended testis. The older children who had delayed puberty were also evaluated with respect to DSD. As a part of evaluation of XY DSD, abdominopelvic ultrasound, karyotype, hormone measurement (testosterone, FSH, LH), FISH analysis with SRY probing, genitogram, laparoscopy, gonadal biopsy and HCG stimulation test were performed. Frequencies and percentages applied on categorical data whereas mean, median, standard deviation were calculated for continuous data. RESULTS A total of 187 patients met the criteria of XY DSD. Age ranged from 1 month to 15 years, 55 (29.4%) presented in infancy, 104 (55.6%) between 1 and 10 years and 28 (15%) older than 10 years. Twenty five (13.4%) were raised as female and 162 as (86.6%) male. The main complaints were ambiguous genitalia, unilateral cryptorchidism, bilateral cryptorchidism, micropenis, delayed puberty, hypospadias, female like genitalia with gonads, inguinal mass. The karyotype was 46 XY in 183 (97.9%), 46 XX in 2 (1.1%), 47 XXY in 1 (0.5%), 45 X/46 XY in 1 (0.5%) patient. HCG stimulation test showed low testosterone response in 43 (23 %), high testosterone response in 62 (33.2%), partial testosterone response in 32 (17.1%) and normal testosterone response in 50 (26.7%). Genitogram was carried out in 86 (45.98%) patients. Presumptive etiological diagnosis of androgen sensitivity syndrome/ 5-alpha reductase deficiency, testicular biosynthetic defect/ leydig cell hypoplasia, partial gonadal dysgenesis, ovotesticular DSD, XX testicular DSD, mixed gonadal dysgenesis, testicular vanishing syndrome, klinefelter syndrome, hypogonadotropic hypogonadism, isolated hypospadias and isolated micropenis was made. CONCLUSION Clinical, chromosomal and hormonal assessment may help in making the presumptive etiological diagnosis. Further molecular genetics analysis are needed in differentiating these abnormalities and to make a final diagnosis.

Clinical, hormonal and chromosomal analysis of undervirilized male/46XY DSD – a 3years experience of national institute of child health

Methodology This study was conducted in National Institute of Child Health at Department of Pediatrics, Division of Endocrinology from January 2008 to December 2010. A Total of 127 Patient under age of 14 years with ambiguity, micropenis, hypospadias, cryptorchism and delayed puberty were selected and studied.USG Pelvis, HCG Stimulation test and Chromosomal analysis were carried out in all patients. Two types of HCG stimulation test were performed. Short HCG was done in children ten and less than ten years of age. Prolong HCG was performed in children more than ten years of age. Laproscopy and biopsy were carried out in patients who had mullerian duct structure on USG and also in patients with no gonads. FISH analysis was done in patients who were 46XX karyotype with testes.

Perceptions of parents and healthcare professionals regarding minimal invasive tissue sampling to identify the cause of death in stillbirths and neonates: a qualitative study protocol

BackgroundGlobally, around 2.6 million neonatal deaths occur world-wide every year and the numbers of stillbirths is almost similar. Pakistan is ranked among the highest countries in the world for neonatal mortality. In 2016, for every 1000 babies born in Pakistan, 46 died before the end of the first month of life. Also, Pakistan had the highest rate of stillbirths (43.1/1000 births) in 2015. To meet sustainable development (SDG) targets of reducing neonatal mortality and stillbirths, it is essential to gain understanding about the causes of neonatal death and stillbirths. In Pakistan, full autopsies are conducted only in medico-legal cases and are very rarely performed to identify a definitive cause of death (CoD) and because of cost and insufficient staff are generally not feasible. Recently, minimally invasive tissue sampling (MITS) has been used to determine CoD in neonates and stillbirths as it addresses some of the socio-cultural and religious barriers to autopsy. However, it is not known how families and communities will perceive this procedure; therefore, exploring family and healthcare professionals’ perceptions regarding MITS is essential in determining acceptable and feasible approaches for Pakistan.MethodsThe study will employ an exploratory qualitative research design. The study will be conducted at the National Institute of Child Health (NICH) hospital of Karachi. The data collection method will consist of key-informant interviews (KIIs) and focus group discussions (FGDs). FGDs will be conducted with the families and relatives of newborns who are visiting the outpatient department (OPD) and well-baby clinics of NICH hospital. KIIs will be conducted with the NICH - medical director, healthcare providers, professionals involved in proceedings related to death and dying, religious leaders, health sector representatives from the government, public health experts, maternal and child health (MCH) specialists, obstetricians and neonatologists and experts from the bioethics committee. Study data will be analyzed using NVivo 10 software.DiscussionThe research will help explore specific cultural, religious and socio-behavioral factors that may increase or decrease the acceptability of MITS for identifying COD in neonates and stillbirths. The findings of the qualitative study will provide a better understanding of parents’ and healthcare professionals’ attitudes towards the use of MITS on neonatal deaths and stillborns.