Whole exome sequencing identifies a novel pathogenic variation [p.(Gly194valfs*7)] in SLC45A2 in the homozygous state in multiple members of a family with oculocutaneous albinism in southern India.

Deleterious mutations within the SLC45A2 gene, encoding membrane-associated transporter protein (MATP), are responsible for type 4 oculocutaneous albinism. The cytogenetic location of SLC45A2 is 5p13.2 and it comprises seven exons located over around 40 kb. Its encoded protein, MATP, is 530 amino acids long and has 12 putative transmembrane domains. MATP is synthesized within melanocytes. It is in these cells that melanogenesis takes place and the melanin is contained within specialized organelles called melanosomes. Previous studies have shown that when MATP expression was reduced using small interfering RNA in MNT-1 melanoma cells, pH was lowered within melanosomes, they became poorly melanized and tyrosinase activity within melanocytes was also reduced. This type of albinism produces a broad spectrum of phenotypes, ranging from complete absence of melanin to brown hair and brown irides. In the current study, blood was collected from a family in which four members had oculocutaneous albinism, showing a complete absence of melanin in skin, hair and eyes. Screening of the TYR gene using the extracted DNA showed no mutation and therefore whole exome sequencing analysis was performed. A novel deletion mutation c.579delG [p.(Gly194Valfs*7)] in the SLC45A2 gene, predicted to be pathogenic and to result in both frameshift and premature termination of the MATP chain, was identified. These data add to the information pertaining to the mutation spectrum of OCA4.

Report of second case and clinical and molecular characterization of Eiken syndrome.

We report a boy with Eiken syndrome caused by a homozygous missense variant in Parathyroid hormone 1 receptor (PTH1R) c.103G > A [p.(Glu35Lys)]. Eiken syndrome is a very rare skeletal dysplasia due to bi-allelic variants in PTH1R. Only one affected family has been known to-date. The hallmarks include delayed ossification of bone including the epiphyses, pubic symphysis, and primary ossification centers of the short tubular bones, coarse bone trabeculae, and modeling abnormalities. The phenotype being described here recapitulates the delayed ossification and modeling abnormalities of Eiken syndrome. In addition, supernumerary epiphyses of the tubular bones of the hands and primary failure of eruption of teeth were observed in our proband. This report characterizes Eiken syndrome and confirms that bi-allelic hypomorphic variants in PTH1R are probably to cause this condition.

A review of skeletal dysplasia research in India.

We aimed to review the contributions by Indian researchers to the subspecialty of skeletal dysplasias (SDs). Literature search using specific keywords in PubMed was performed to retrieve all the published literature on SDs as on July 6, 2017. All published literature on SDs wherein at least one author was from an Indian institute was included. Publications were grouped into different categories based on the major emphasis of the research paper. Five hundred and forty publications in English language were retrieved and categorized into five different groups. The publications were categorized as reports based on: (i) phenotypes (n = 437), (ii) mutations (n = 51), (iii) novel genes (n = 9), (iv) therapeutic interventions (n = 31), and (v) reviews (n = 12). Most of the publications were single-patient case reports describing the clinical and radiological features of the patients affected with SDs (n = 352). We enlisted all the significant Indian contributions. We have also highlighted the reports in which Indians have contributed to discovery of new genes and phenotypes. This review highlights the substantial Indian contributions to SD research, which is poised to reach even greater heights given the size and structure of our population, technological advances, and expanding national and international collaborations.

Seven additional families with spondylocarpotarsal synostosis syndrome with novel biallelic deleterious variants in FLNB.

The location and/or type of variants in FLNB result in a spectrum of osteochondrodysplasias ranging from mild forms, like spondylocarpotarsal synostosis syndrome and Larsen syndrome, to severe perinatal lethal forms, such as atelosteogenesis I and III and Boomerang dysplasia. Spondylocarpotarsal synostosis syndrome is characterized by disproportionate short stature, vertebral anomalies and fusion of carpal and tarsal bones. Biallelic loss-of-function variants in FLNB are known to cause spondylocarpotarsal synostosis syndrome and 9 families and 9 pathogenic variants have been reported so far. We report clinical features of 10 additional patients from 7 families with spondylocarpotarsal synostosis syndrome due to 7 novel deleterious variants in FLNB, thus expanding the clinical and molecular repertoire of spondylocarpotarsal synostosis syndrome. Our report validates key clinical (fused thoracic vertebrae and carpal and tarsal coalition) and molecular (truncating variants in FLNB) characteristics of this condition.

Novel KIAA0753 mutations extend the phenotype of skeletal ciliopathies.

The skeletal ciliopathies are a heterogeneous group of disorders with a significant clinical and genetic variability and the main clinical features are thoracic hypoplasia and short tubular bones. To date, 25 genes have been identified in association with skeletal ciliopathies. Mutations in the KIAA0753 gene have recently been associated with Joubert syndrome (JBTS) and orofaciodigital (OFD) syndrome. We report biallelic pathogenic variants in KIAA0753 in four patients with short-rib type skeletal dysplasia. The manifestations in our patients are variable and ranging from fetal lethal to viable and moderate skeletal dysplasia with narrow thorax and abnormal metaphyses. We demonstrate that KIAA0753 is expressed in normal fetal human growth plate and show that the affected fetus, with a compound heterozygous frameshift and a nonsense mutation in KIAA0753, has an abnormal proliferative zone and a broad hypertrophic zone. The importance of KIAA0753 for normal skeletal development is further confirmed by our findings that zebrafish embryos homozygous for a nonsense mutation in kiaa0753 display altered cartilage patterning.

Second family provides further evidence for causation of Steel syndrome by biallelic mutations in COL27A1.

Steel syndrome is a rare disorder of the skeleton characterized by facial dysmorphism, short stature, carpal coalition, dislocated radial heads, bilateral hip dislocation and vertical talus. Homozygous variants in COL27A1 were reported in an extending family from Puerto Rico. Here, we report a 5-year-old girl from a non-consanguineous family with facial dysmorphism, short stature, carpal coalition, dislocation of radial heads, bilateral hip dislocation, scoliosis and vertical talus. Exome sequencing identified 2 novel compound heterozygous variants c.521_528del (p.(Cys174Serfs*34)) and c.2119C>T (p.(Arg707*)) in COL27A1 in this child and the parents were heterozygous carriers. We hence report the second molecularly proven case of Steel syndrome and the first case to be reported among non-Puerto Rican population. Our report further validates the role of COL27A1 mutations in causation of Steel syndrome.

A homozygous nonsense variant in IFT52 is associated with a human skeletal ciliopathy.

Intraflagellar transport (IFT) is vital for the functioning of primary cilia. Defects in several components of IFT complexes cause a spectrum of ciliopathies with variable involvement of skeleton, brain, eyes, ectoderm and kidneys. We examined a child from a consanguineous family who had short stature, narrow thorax, short hands and feet, postaxial polydactyly of hands, pigmentary retinopathy, small teeth and skeletal dysplasia. The clinical phenotype of the child shows significant overlap with cranioectodermal dysplasia type I (Sensenbrenner syndrome). Whole-exome sequencing revealed a homozygous nonsense variant p.R142* in IFT52 encoding an IFT-B core complex protein as the probable cause of her condition. This is the first report of a human disease associated with IFT52.

Prenatal diagnosis of absent pulmonary valve confirmed by autopsy.

Absent pulmonary valve syndrome (APVS) is a rare congenital cardiac anomaly. This syndrome is comprised of subtotal or total absence of pulmonary valve leaflets, stenosis of the pulmonary artery orifice, aneurysmal dilation of the main pulmonary artery and ventricular septal defect. We report a case of APVS with neural tube defect detected prenatally at 22 weeks of gestation by echocardiography, and subsequently confirmed by autopsy of the still born fetus. The common presentations, means of diagnosis and variants of APVS are discussed in brief.

Analysis of the WISP3 gene in Indian families with progressive pseudorheumatoid dysplasia.

Progressive pseudorheumatoid dysplasia (PPD) is a progressive skeletal syndrome characterized by stiffness, swelling and pain in multiple joints with associated osteoporosis in affected patients. Radiographically, the predominant features resemble a spondyloepiphyseal dysplasia. Mutations in the WISP3 gene are known to cause this autosomal recessive condition. To date, only a limited number of studies have looked into the spectrum of mutations causing PPD. We report on clinical features and WISP3 mutations in a large series of Indian patients with this rare skeletal dysplasia. Families with at least one member showing clinical and radiologic features of PPD were recruited for the study. Symptoms, signs and radiographic findings were documented in 35 patients from 25 unrelated families. Swelling of small joints of hands and contractures are the most common presenting features. Mutation analysis was carried out by bidirectional sequencing of the WISP3 gene in all 35 patients. We summarize the clinical features of 35 patients with PPD and report on 11 different homozygous mutations and one instance of compound heterozygosity. Eight (c.233G>A, c.340T>C, c.348C>A, c.433T>C, c.682T>C, c.802T>G, c.947_951delAATTT, and c.1010G>A) are novel mutations and three (c.156C>A, c.248G>A, and c.739_740delTG) have been reported previously. One missense mutation (c.1010G>A; p.Cys337Tyr) appears to be the most common in our population being seen in 10 unrelated families. This is the largest cohort of patients with PPD in the literature and the first report from India on mutation analysis of WISP3. We also review all the mutations reported in WISP3 till date.

Placental Teratoma Presenting as a Lobulated Mass behind the Neck of Fetus: A Case Report.

Placental teratoma is a rare nontrophoblastic benign tumour, which is thought to arise from germ cells. These tumours contain elements derived from multiple germ cell layers. We report a case of teratoma, where on ultrasound; there were two echogenic masses of 4 cm × 5 cm and 3 cm × 4 cm, arising from the placenta. Elective lower segment cesarean section was done in view of breech presentation at 38 weeks of gestation. Gross examination of the placenta showed two lobulated masses of 5 cm × 5 cm and 4 cm × 4.5 cm, respectively. Histopathological examination of the placenta was suggestive of teratoma of the placenta. The fetus was normal.The maternal and fetal outcome was good.

Preimplantation diagnosis of genetic diseases.

One of the landmarks in clinical genetics is prenatal diagnosis of genetic disorders. The recent advances in the field have made it possible to diagnose the genetic conditions in the embryos before implantation in a setting of in vitro fertilization. Polymerase chain reaction and fluorescence in situ hybridization are the two common techniques employed on a single or two cells obtained via embryo biopsy. The couple who seek in vitro fertilization may screen their embryos for aneuploidy and the couple at risk for a monogenic disorder but averse to abortion of the affected fetuses after prenatal diagnosis, are likely to be the best candidates to undergo this procedure. This article reviews the technique, indications, benefits, and limitations of pre-implantation genetic testing in clinical practice.

Unusual facial cleft in Fryns syndrome: defect of stomodeum?

Unusual facial cleft in Fryns syndrome: defect of stomodeum?: We report on a fetus with Fryns syndrome. The facial cleft was unusual. There was bilateral cleft lip with cleft palate. The intermaxillary segment was connected through the base of a mound in the midline to the lower lip. We believe this is an atypical facial cleft in Fryns syndrome and likely represents a defective stomodeum.

Opsismodysplasia.

Opsismodysplasia is a rare osteochondrodysplasia with micromelia and platyspondyly. We report on a neonate with opsismodysplasia. During the antenatal period, polyhydramnios was noted. This is the first report of opsismodysplasia from India. Significant observation was antenatal polyhydramnios.

Massive cranial osteolysis, skin changes, growth retardation and developmental delay: Gorham syndrome with systemic manifestations?

We report on a 16-month-old girl with multiple swellings on her skull due to massive osteolysis, growth retardation, facial anomalies, and wrinkly skin with mosaic hypopigmentation. She also had severe hypercalcemia, which gradually returned to normal levels. The condition likely represents Gorham syndrome with systemic manifestations.

Fabry disease: a treatable lysosomal storage disorder.

Fabry disease is a lysosomal storage disease with an X-linked inheritance pattern, which presents in childhood as acroparaesthesias. Its non-specific symptoms often lead to delays in the diagnosis. We report the case of a 13-year-old boy who presented with typical acroparaesthesia of Fabry disease, his younger brother had gastrointestinal manifestations of the disease and their mother's symptoms suggested that she is a carrier. Enzyme replacement therapy helped in ameliorating the patient's symptoms and preventing complications such as renal failure, stroke and cardiovascular disorders.

Long-term efficacy of oral deferiprone in management of iron overload in beta thalassemia major.

OBJECTIVE: Variable response to deferiprone has been observed in the management of iron overload in patients with thalassemia major. Our objective was to assess the long-term efficacy of deferiprone in patients with thalassemia major. METHODS: We analyzed the serum ferritin levels in fifty-eight patients who were on deferiprone therapy for at least three years. We divided patients into three groups based on the initial serum ferritin level: group 1, <2000 ng/ml; group 2, 2000-4000 ng/ml; group 3, <4000 ng/ml. RESULTS: Repeated measurement analysis showed a fall in serum ferritin level in group 3 after 12 months but again increased after 24 months, whereas other groups showed an increase in serum ferritin after 12 months which was sustained for 3 years. The patients were divided into three groups depending on the comparison of serum ferritin at the beginning and at the end; response group I: patients remained in the same ferritin group (n=30), response group II: patients progressed to more severe group (n=17), response group III: serum ferritin decreased and patient shifted to the lower group of ferritin level (n=11). Comparing various factors which could affect the response to deferiprone among three groups, no factor other than serum ferritin at the beginning of the treatment showed significant effect. However, some patients with a serum ferritin value in the lower range also showed improvement. CONCLUSION: The major factor determining the response to deferiprone was initial serum ferritin. But some patients responded well even with relatively low initial serum ferritin.

Novel mutation and atlantoaxial dislocation in two siblings from India with Dyggve-Melchior-Clausen syndrome.

Dyggve-Melchior-Clausen syndrome is a rare variety of spondyloepimetaphyseal dysplasia which often resembles Morquio syndrome. We describe two siblings from India with the condition and report a novel homozygous mutation in them (c.1172_1173insC). One of them had atlantoaxial dislocation.

Synpolydactyly and HOXD13 polyalanine repeat: addition of 2 alanine residues is without clinical consequences.

BACKGROUND: Type II syndactyly or synpolydactyly (SPD) is clinically very heterogeneous, and genetically three distinct SPD conditions are known and have been designated as SPD1, SPD2 and SPD3, respectively. SPD1 type is associated with expansion mutations in HOXD13, resulting in an addition of > or = 7 alanine residues to the polyalanine repeat. It has been suggested that expansions < or = 6 alanine residues go without medical attention, as no such expansion has ever been reported with the SPD1 phenotype. METHODS: We describe a large Pakistani and an Indian family with SPD. We perform detailed clinical and molecular analyses to identify the genetic basis of this malformation. RESULTS: We have identified four distinct clinical categories for the SPD1 phenotype observed in the affected subjects in both families. Next, we show that a milder foot phenotype, previously described as a separate entity, is in fact a part of the SPD1 phenotypic spectrum. Then, we demonstrate that the phenotype in both families segregates with an identical expansion mutation of 21 bp in HOXD13. Finally, we show that the HOXD13 polyalanine repeat is polymorphic, and the expansion of 2 alanine residues, evident in unaffected subjects of both families, is without clinical consequences. CONCLUSION: It is the first molecular evidence supporting the hypothesis that expansion of < or = 6 alanine residues in the HOXD13 polyalanine repeat is not associated with the SPD1 phenotype.

S252W mutation in Indian patients of Apert syndrome.

Two common mutations in the exon IIIa of fibroblast growth factor receptor 2 account for majority of the cases of Apert syndrome. They can be analyzed by amplifying the segment followed by testing for the abolition of restriction sites. We evaluated two children with typical features of Apert syndrome. A segment of FGFR2 exon IIIa was amplified by polymerase chain reaction. Restriction fragment length polymorphism was analyzed using enzymes MboI and BglI respectively for S252W and P253R mutations. The DNA segment was sequenced using ABI 310 automated DNA fragment analyzer. Both the patients showed S252W mutations. DNA sequencing confirmed the results of the restriction fragment length polymorphism. Our study is the first report from Indian subcontinent to show the prevalence of S252W mutation among Apert syndrome patients from Indian origin.