Netherton syndrome-A therapeutic challenge in childhood.

Key Clinical Message: High-dose intravenous immunoglobulin exhibits great potential in the treatment of Netherton syndrome. Abstract: Netherton syndrome (NS) is a rare autosomal recessive genodermatosis (OMIM #256500) characterized by superficial scaling, atopic manifestations, and multisystemic complications. It is caused by loss-of-function mutations in the SPINK5 gene, which encode a key kallikrein protease inhibitor. There are two subtypes of the syndrome that differ in clinical presentation and immune profile: ichthyosiform erythroderma and ichthyosis linearis circumflexa. NS is a multisystemic disease with numerous extracutaneous manifestations. Current therapy for patients with NS is mainly supportive, as there is no curative or specific treatment, especially for children with NS, but targeted therapies are being developed. We describe an 8-year-old boy with genetically proven NS treated with intravenous immunoglobulin for recurrent skin and systemic infections from infancy, growth retardation, and associated erythroderma. Under this therapy, his skin status, infectious exacerbations, and quality of life all improved. Knowledge of the cytokine-mediated pathogenesis of NS and the development of new biologic drugs open new possibilities for NS patients. However, the different therapeutic options have been applied in a limited number of cases, and variable responses have been shown. Randomized controlled trials with a sufficient number of patients stratified and treated according to their specific immune profile and clinical phenotype are needed to evaluate the safety and efficacy of treatment options for patients with NS.

Retrospective Diagnosis of Pontocerebellar Hypoplasia Type 1B in a Family with Two Deceased Newborn Children.

Pontocerebellar hypoplasia type 1B is a severe autosomal recessive neurologic disorder characterized by a combination of cerebellar and spinal motor neuron degeneration beginning at birth. Pontocerebellar hypoplasia type 1B is caused by mutations in EXOSC3 gene. High prevalence of the p.Gly31Ala mutation was found recently, especially in the Roma ethnic minority. We present a young Bulgarian Roma family with two deceased newborn children manifesting severe neuromuscular disorder including severe muscle weakness, respiratory distress, and multiple joint contractures. Based on the clinical signs and family's population characteristics, DNA testing for the previously described EXOSC3 in Bulgarian Roma mutation c.92G > C; p.Gly31Ala was performed on blood samples of both parents and they were found to be heterozygous carriers. This finding indirectly confirmed the diagnosis of pontocerebellar hypoplasia type B in the deceased offspring. Knowledge of population-specific molecular bases of genetic conditions was the key to final diagnosis in the presented family. Designing of population-based clinical-genetic panels may be a powerful diagnostic tool for patients with such origin. Preconception carrier screening in high-risk population groups is a feasible option to discuss.

Triploidy in a Live-Born Extremely Low Birth Weight Twin: Clinical Aspects.

Triploidy is a rare chromosomal aberration characterized by a karyotype with 69 chromosomes. Triploid fetuses usually are miscarried in early pregnancy. We present a case of a triploid twin and a genetically unaffected co-twin, conceived through in vitro fertilization. A discordant growth was registered at 20 weeks of gestation. Cesarean section was performed at 35 5/7 gestational week. The second twin was extremely growth restricted female (780 g) with oligohydramnios and severe respiratory distress, and died at 20 hours of age. The autopsy revealed unilobar left lung, bilobar right lung, and cysts of the terminal bronchioles. Quantitative fluorescent polymerase chain reaction detected triploidy compatible pattern. So, early intrauterine growth restriction may be a sign of triploidy, which must be proven by pre or postnatal genetic testing.

New Territory for an Old Disease: 5-Alpha-Reductase Type 2 Deficiency in Bulgaria.

Disorders/differences of sexual development (DSD) are a group of conditions, some of which can be clinically indistinguishable mainly due to their phenotypic variability. Defining the molecular basis of their wide spectrum is still in progress. The diagnosis of 5-alpha-reductase type 2 (5α-reductase-2) deficiency is difficult especially in newborns and pre-pubertal individuals, and as a result its frequency might be underestimated. In the present study, we describe the clinical characteristics and molecular defects in 3 nonrelated 5α-reductase-2 deficiency patients of Bulgarian descent. Sequencing analysis revealed the mutations p.Y188CfsX9 and p.G196S, and MLPA analysis showed a deletion of exon 1 in the SRD5A2 gene. The observed genetic substitutions were not detected in 76 additionally screened unrelated controls, but a heterozygous healthy carrier of the p.R171S mutation was found. This is the first study on the molecular basis of 5α-reductase-2 deficiency in Bulgaria. It suggests that the carrier frequency of mutations in the SRD5A2 gene might be noteworthy worldwide. There is no correlation between cultural aspects, location, and/or population size and the number of different mutations in SRD5A2 detected, and more efforts should be made to determine the prevalence of this condition in different geographic areas. Our study supports the importance of genetic testing in 46,XY DSD patients, especially in countries or regions where 5α-reductase-2 deficiency has not been reported so far.

2q31.1 microdeletion syndrome: redefining the associated clinical phenotype.

INTRODUCTION: The clinical phenotype of the chromosome 2q31 deletion syndrome consists of limb anomalies ranging from monodactylous ectrodactyly, brachydactyly and syndactyly to camptodactyly. Additional internal organ anomalies-for example, heart defects, ocular anomalies-may be present. Hemizygosity for HOXD13 and EVX2 genes was thought to cause the observed skeletal defects. Recently, based on the phenotype of patients with overlapping 2q31 interstitial deletions, a new SHFM5 locus was proposed, proximal to the HOXD cluster, between EVX2 and marker D2S294. DLX1 and DLX2 haploinsufficiency was suggested as the most plausible explanation for the observed SHFM-like limb anomalies in these cases. METHODS AND RESULTS: Five unique, interstitial 2q31 deletion patients were selected to further characterise the 2q31 region and to establish a genotype/phenotype correlation map. The size of the deletions was delineated with a chromosome 2 specific tiling path bacterial artificial chromosome (BAC) array. The clinical and molecular data for this group of patients were compared to others in the literature. A common locus for the observed skeletal anomalies, including the HOXD genes and surrounding regulatory sequences, was delineated. These results correlate with recently published studies in animal models. In addition, a critical region for the facial gestalt of the 2q31.1 microdeletion syndrome was delineated. CONCLUSIONS: These results reinforce the hypothesis that the variable skeletal phenotype in 2q31 deletion patients is a result of hemizygosity for the HOXD genes and that the 2q31.1 microdeletion syndrome is a well defined and clinically recognisable phenotype.

Hypertrichosis in patients with SURF1 mutations.

We present three patients with SURF1 mutations. In addition to Leigh syndrome all patients had hypertrichosis, a clinical sign that is not usually associated with Leigh syndrome. The hypertrichosis was not congenital and it was mainly distributed on the extremities and forehead. In addition to our three patients, we have identified five patients in the literature with hypertrichosis and Leigh syndrome due to SURF1 mutations. Since most patients had onset of hypertrichosis before the diagnosis of Leigh syndrome was made, we suggest that clinicians consider Leigh syndrome in patients with, for example, psychomotor retardation or other unspecific symptoms in combination with hypertrichosis.