Expanding the comprehensive national neonatal screening programme in the United Arab Emirates from 1995 to 2011.

The national neonatal screening programme in the United Arab Emirates currently includes 16 disorders: congenital hypothyroidism, sickle-cell diseases, congenital adrenal hyperplasia, biotinidase deficiency and 12 amino acid, organic acid and fatty acid disorders. This paper reports data since the programme started in January 1995 up to December 2011 on the incidence of screened disorders and the molecular basis of positive screened cases. Screening used a combination of tandem mass spectrometry, molecular technologies and biochemical analysis. A total of 750 365 infants were screened and 717 babies saved from associated morbidity and/or mortality. The incidence of screened disorders were 1:1 873 for congenital hypothyroidism, 1:14 544 for phenylketonuria, 1:3 526 for amino acid, organic acid and fatty acid disorders, 1:9 030 for classical congenital adrenal hyperplasia, 1:8 300 for biotinidase deficiency, 1:2 384 for sickle-cell disease and 1:121 for sickle-cell traits. Coverage of neonatal screening in the population reached 95% in 2010.

Severe exfoliative erythema of malnutrition in a child with coexisting coeliac and Hartnup's disease.

Exfoliative erythema of malnutrition is a collective term for skin lesions caused by a combination of multiple deficiencies in vitamins, microelements, essential fatty acids and amino acids. We report a 3-year-old Iraqi girl with malnutrition due to coexisting coeliac and Hartnup's disease. On admission to hospital, she presented with kwashiorkor, anaemia, hepatitis and hypoalbuminia. She had severe skin changes with erythema, desquamation, erosions and diffuse hyperpigmentation involving the whole integument, particularly the perioral area, trunk and legs. She also had angular cheilitis, glossitis, conjunctivitis and diffuse alopecia. After treatment with a high-protein gluten-free diet and supplementation with vitamins and microelements there was a rapid improvement in the skin lesions. The severity of the skin lesions in this case can be explained by the coexistence of two metabolic diseases causing complex malnutrition.

Mutations of the E1beta subunit gene (PDHB) in four families with pyruvate dehydrogenase deficiency.

Pyruvate dehydrogenase complex (PDC) deficiencies are a major cause of primary lactic acidosis. Most cases result from mutations of the gene for the pyruvate dehydrogenase E1alpha subunit (PDHA1), with fewer cases resulting from mutations in genes for E3, E3-binding protein, E2, and the E1beta subunit (PDHB). We have found four cases of PDHB mutations among 83 analyzed cases of PDC deficiency. In this series, PDHB mutations were found to be about 10% as frequent as PDHA1 mutations. All cases were diagnosed by low PDC activity, with normal E2 and E3 activities. These included a 6.5-year-old male (consanguineous, homozygous R36C); a neonatal female who died soon after birth, (compound heterozygous C306R/D319V), a 26-year-old female (heterozygous I142M/W165S), and a 13month old female (consanguineous, homozygous Y132C) who is a sibling of a previously published case. Their ethnic background is diverse (Caucasian, Arab, and African American descent). All cases had lactic acidosis and developmental delay. Three cases had agenesis of the corpus callosum, seizures, and hypotonia; one died within the first year of life. These clinical findings are similar to those of PDHA1 deficiency, except that ataxia was more frequent in PDHA1 cases and consanguinity was found only in PDHB families. PDC activity in lymphocytes from six parents is normal, who all are heterozygous carriers for the respective mutations. Immunoreactivity of E1beta was markedly reduced in one case and showed a slightly larger form of E1beta in one case. Computer analysis predicts that: R36C affects the interaction of several amino acids resulting in conformational change, C306R affects interaction of the two beta subunits, D319 is in the interface of E1 and E2, I142M affects conformation around a K ion affecting stability of the beta subunit, W165S affects hydrophobic interaction between the beta subunits, and Y132C affects interaction between the beta subunits. All of these residues are conserved in E1beta across species, and Y132 is also conserved in other TPP-requiring enzymes. These observations support the conclusion that these are pathogenic mutations.

A new autosomal recessive syndrome of ocular colobomas, ichthyosis, brain malformations and endocrine abnormalities in an inbred Emirati family.

We report on an inbred Emirati family of Baluchi origin with ocular colobomas, ichthyosis, and endocrine abnormalities associated with midline brain malformations and mental retardation. All affected children had ocular colobomas, developmental delay and midline brain malformations. Hypoplastic pituitary gland was present in all three investigated children. Ichthyosiform dermatitis appeared in infancy in all surviving children. Other variable features include congenital heart defects, hypertrichosis and dark skin involving the dorsum of hands and feet associated with mild degree of palmo-plantar keratoderma. Some of the features in this family overlap the CHIME (Coloboma of the eye, Heart defect, Ichthyosiform dermatosis, Mental retardation, and Ear defect) syndrome. However, several features described in CHIME syndrome were not present in these children. These include deafness, seizures, oligodontia, and hair abnormalities. Some of the features in these children also overlap with septo-optic dysplasia (SOD) but optic nerve hypoplasia, mandatory for the diagnosis of SOD, was present in one child only. We suggest that these children have a new autosomal recessive syndrome of ocular colobomas and ichthyosis.

Several homozygous mutations in the gene for 11 beta-hydroxysteroid dehydrogenase type 2 in patients with apparent mineralocorticoid excess.

Four deleterious mutations are described in the gene for HSD11B2, which encodes the type 2 isoenzyme of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD2). In seven families with one or more members affected by apparent mineralocorticoid excess, this disorder is shown to be the result of a deficiency in 11 beta HSD2. Surprisingly, the patients are all homozygous for their mutation. This results from consanguinity in two families and possibly from endogamy or a founder effect in four of the other five families. The absence of compound heterozygotes remains to be investigated.

Examination of genotype and phenotype relationships in 14 patients with apparent mineralocorticoid excess.

Apparent mineralocorticoid excess (AME) is a genetic disorder causing pre- and postnatal growth failure, juvenile hypertension, hypokalemic metabolic alkalosis, and hyporeninemic hypoaldosteronism due to a deficiency of 11 beta-hydroxysteroid dehydrogenase type 2 enzyme activity (11 beta HSD2). The 11 beta HSD2 enzyme is responsible for the conversion of cortisol to the inactive metabolite cortisone and therefore protects the mineralocorticoid receptors from cortisol intoxication. Several homozygous mutations are associated with this potentially fatal disease. We have examined the phenotype, biochemical features, and genotype of 14 patients with AME. All of the patients had characteristic signs of a severe 11 beta HSD2 defect. Birth weights were significantly lower than those of their unaffected sibs. The patients were short, underweight, and hypertensive for age. Variable damage of one or more organs (kidneys, retina, heart, and central nervous system) was found in all of the patients except one. The follow-up studies of end-organ damage after 2-13 yr of treatment in six patients demonstrated significant improvement in all patients. The urinary metabolites of cortisol demonstrated an abnormal ratio with predominance of cortisol metabolites, i.e. tetrahydrocortisol plus 5 alpha-tetrahydrocortisol/tetrahydrocortisone was 6.7-33, whereas the normal ratio is 1.0. Infusion of [11-3H]cortisol resulted in little release of tritiated water, indicating the failure of the conversion of cortisol to cortisone. Thirteen mutations in the HSD11B2 gene have been previously published, and we report three new genetic mutations in two patients, one of whom was previously unreported. All of the patients had homozygous defects except one, who was a compound heterozygote. Our first case had one of the most severe mutations, resulting in the truncation of the enzyme 11 beta HSD2, and died at the age of 16 yr while receiving treatment. Three patients with identical homozygous mutations from different families had varying degrees of severity of clinical and biochemical features. Due to the small number of patients with identical mutations, it is difficult to correlate genotype with phenotype. In some cases, early and vigilant treatment of AME patients may prevent or improve the morbidity and mortality of end-organ damage such as renal or cardiovascular damage and retinopathy. The outcome of treatment in more patients may establish the efficacy of treatment.

Adrenoleukodystrophy: cortical hypoperfusion demonstrated with 99mTc-HMPAO SPECT.

Regional cerebral blood flow was investigated in an 8-year-old boy with adrenoleukodystrophy by single photon emission computed tomography. The use of 99mTc-hexamethylpropylene amine oxime revealed markedly reduced blood flow in the occipital, parietal, and temporal cortical gray matter, in addition to the anticipated reduction in white matter. The area with a decreased blood flow was more extensive than that detected by x-ray computed tomography.

Congenital insensitivity to pain with anhidrosis.

Congenital insensitivity to pain with anhidrosis is an autosomal-recessive disorder resulting from defective neural crest differentiation with loss of the first-order afferent system, which is responsible for pain and temperature sensation. There is also a neuronal loss in the sympathetic ganglia. Lack of sweating, hyperthermia, and infections of bones are main features of the disorder; however, contradictory results have been published regarding eccrine sweat gland innervation. A 5-year-old male patient with typical clinical manifestations of congenital insensitivity to pain with anhidrosis is presented. Immunohistochemistry with antibodies against S100 protein and neuron-specific enolase failed to reveal nerve fibers in the vicinity of the eccrine sweat glands. The roles of the nerve growth factor and tyrosine kinase receptor gene mutations in the pathogenesis of the disease are also discussed.

Pneumatosis and pneumoperitoneum in chronic idiopathic intestinal pseudoobstruction.

Chronic idiopathic intestinal pseudoobstruction is a diagnosis of exclusion for the rare patient with severe small bowel atony without any demonstrable organic cause. The very poor prognosis associated with this disease has been somewhat improved with the advent of parenteral nutrition; nevertheless, these patients follow a stormy course characterized by malnutrition, recurrent obstruction, infection, hemorrhage, and perforation. We describe a 16-year-old boy with this disease who presented to us with vague abdominal pain and pneumoperitoneum. Laparotomy showed pneumatosis cystoides intestinalis without intestinal perforation. The presence of free air in the abdominal cavity is an almost pathognomonic sign of intestinal perforation. Pneumatosis cystoides intestinalis is one of the very few nonsurgical causes of pneumoperitoneum. Beyond the neonatal period, in which it is the hallmark of necrotizing enterocolitis, it has been described in patients with severe obstructive lung disease, in collagenous disorders, and in the short-bowel syndrome. In the present case, it may have resulted from chronic intestinal distension, allowing air under pressure to dissect through the bowel wall. The challenge of such a unique association of conditions lies in the avoidance of unnecessary surgery in a chronic, essentially nonsurgical disease while avoiding unnecessary delay in a possibly acute surgical event.

Further delineation of Hennekam syndrome.

We report four children from four inbred Arab families with varying manifestations of Hennekam syndrome and additional features that have not been previously reported. These include abnormalities of the middle ear, anomalous pulmonary venous drainage, interrupted inferior vena cava, polysplenia, crossed renal ectopia, median position of the liver and multiple cavernous haemangiomas. In addition, in one case lymphoedema was absent and oedema due to hypoproteinaemia appeared at 6 years of age. Since anomalies of the veins and the consequent developmental abnormalities of the lymphatics might lead to alterations in the fluid balance of the embryo, we hypothesize that altered fluid dynamics due to defective vascular and lymphatic development might disrupt critical events in craniofacial morphogenesis resulting in Hennekam syndrome.

An autosomal recessive syndrome of choanal atresia, hypothelia/athelia and thyroid gland anomalies overlapping bamforth syndrome, ANOTHER syndrome and methimazole embryopathy.

Two sibs from an inbred Arab family are described with an autosomal syndrome of choanal atresia, hypothelia/athelia and thyroid gland anomalies overlapping Bamforth syndrome, ANOTHER syndrome and methimazole embryopathy. In one case the syndrome described was lethal. Cases with similar features are reviewed and genetic mutations discussed.

Mediobasal and mantle defect of the prosencephalon: lobar holoprosencephaly, schizencephaly and diabetes insipidus.

An infant is described who had a combination of lobar holoprosencephaly and open-lip schizencephaly. Midline fusion of the basal ganglia was associated with bilateral absence of abundant parts of the brain mantle. Agenesis of the corpus callosum, hypoplasia of the optic nerves and chiasm, absence of the septum pellucidum, posterior pituitary and olfactory bulbs were further components of the malformation. Blindness, intractable seizures, spastic tetraplegia, somatomental retardation and diabetes insipidus were the main clinical features. A defect in the induction of the mediobasal part of the prosencephalon and failure of cell proliferation can be responsible for this complex malformation. Recent results of homeobox gene research relevant to the development of the prosencephalon are discussed.

Lipoprotein lipase deficiency and transient diabetes mellitus in a neonate.

Lipoprotein lipase deficiency (LPLD) represents a rare ( < 1:100000), life-threatening neonatal condition, and a challenge for dietary management. We describe a neonate who developed diabetes mellitus as a feature of LPLD, without evidence of pancreatitis.

Radiological analysis of children with cystic fibrosis who are homozygous for cystic fibrosis transmembrane conductance regulator mutation S549R (T-->G).

Genotype-phenotype analyses in cystic fibrosis (CF) have shown that cystic fibrosis transmembrane conductance regulator (CFTR) genotypes can predict pancreatic status but that correlations with pulmonary status remain elusive. We investigated the extent and severity of lung disease associated with CFTR mutation S549R (T-->G). This mutation is localized in intron 11 (nucleotide-binding fold 1 of the CFTR protein) and had so far been described as a private mutation only. It is associated with an extremely severe overall CF phenotypic expression. Detailed radiological analyses were performed by a single observer in 12 children with CF from the United Arab Emirates who were homozygous for CFTR mutation S549R (T-->G). A diversity of pulmonary changes included marked hyperinflation in early infancy in conjunction with inflammation of the interstitium. After 2 years of age, signs of central airway involvement occurred in association with early signs of pulmonary hypertension. In conclusion, although there is some diversity in the radiological findings of these CF patients, R549 is a very severe allele associated with extreme lung disease and rapid pulmonary decline.

Genotype-phenotype correlations in cystic fibrosis: clinical severity of mutation S549R(T-->G).

With a view to assessing genotype-to-phenotype correlations in cystic fibrosis (CF), the clinical presentation of CF children from the United Arab Emirates (UAE) who were homozygous for cystic fibrosis transmembrane conductance regulator (CFTR) mutation S549R(T-->G was investigated. This mutation is localized in intron 11 (nucleotide binding domain 1 of the CFTR protein) and had so far been described as a private mutation only. The associations between the R549/R549 genotype and 20 outcome variables, including age at diagnosis, sweat chloride concentrations, growth percentiles, meconium ileus, pancreatic sufficiency, pulmonary disease, associated complications and micro-organism colonization were examined in a group of 15 CF children (9 females and 6 males). Mean current age and age at diagnosis were both low (5.4+/-3.5 and 1.0+/-1.1 yrs, respectively). Although none of the 15 CF patients had presented with meconium ileus at birth, all were pancreatic insufficient and had very severe lung disease, with a high rate of Pseudomonas aeruginosa and Staphylococcus aureus. Two patients died during the course of this investigation (one was 5 months and the other, 6 yrs old). The clinical presentation associated with S549R(T-->G) homozygosity in the United Arab Emirates is quite homogeneous and shows an extreme degree and course of cystic fibrosis severity.

Expanding the comprehensive national neonatal screening programme in the United Arab Emirates from 1995 to 2011

The national neonatal screening programme in the United Arab Emirates currently includes 16 disorders: congenital hypothyroidism, sickle-cell diseases, congenital adrenal hyperplasia, biotinidase deficiency and 12 amino acid, organic acid and fatty acid disorders. This paper reports data since the programme started in January 1995 up to December 2011 on the incidence of screened disorders and the molecular basis of positive screened cases. Screening used a combination of tandem mass spectrometry, molecular technologies and biochemical analysis. A total of 750 365 infants were screened and 717 babies saved from associated morbidity and/or mortality. The incidence of screened disorders were 1:1 873 for congenital hypothyroidism, 1:14 544 for phenylketonuria, 1:3 526 for amino acid, organic acid and fatty acid disorders, 1:9 030 for classical congenital adrenal hyperplasia, 1:8 300 for biotinidase deficiency, 1:2 384 for sickle-cell disease and 1:121 for sickle-cell traits. Coverage of neonatal screening in the population reached 95% in 2010