Assessment of auditory functions in patients with hepatic glycogen storage diseases.

BACKGROUND: Hepatic glycogen storage diseases are a group of diseases manifesting mainly with hypoglycemia and hepatomegaly. The patients require frequent daytime and nocturnal feedings. Hypoglycemia may cause sensorineural hearing loss and nocturnal feeding is a risk factor for the development of gastroesophageal reflux that may cause chronic otitis media and hearing loss consequently. We aimed to determine the prevalence and characteristics of hearing loss in hepatic glycogen storage diseases. METHODS: A total of 24 patients with hepatic glycogen storage disease (15 glycogen storage disease type I and 9 non type I) and 24 age/sex matched healthy controls were enrolled in the study. Pure tone audiometer, immitansmetry, acoustic reflex measurement, otoacoustic emission test (OAE) and auditory brainstem response (ABR) tests were applied to all participants. RESULTS: Hearing loss was determined in 17/24 patients (12 glycogen storage disease type I and 5 non type I) with pure tone audiometer. Interpretation of all the findings revealed a total of 8 patients had conductive and 9 had mixed hearing loss. All parameters were significantly different than the control group. CONCLUSIONS: This is the first study to comprehensively assess the auditory functions of patients with hepatic glycogen storage disease. Audiological findings determined a significantly increased prevalence of conductive/ mixed type hearing loss in the patient group which is a new finding in the literature. Further studies with extended patient numbers are required to enlighten the underlying pathophysiology.

Fucosidosis: clinical and molecular findings of Turkish patients.

BACKGROUND: Fucosidosis is a rare, autosomal recessive lysosomal storage disease caused by alpha L- fucosidase enzyme deficiency in all tissues. Here, we identify a patient with a novel homozygous pathogenic variant and atypical clinical findings and summarized the clinical and molecular features of Turkish patients reported in the literature and present. CASE: The patient was born to consangineous parents at the 28th week of gestation. He had developmental delay that was attributed to prematurity. At he age of 2.5 years, brain magnetic resonans imaging revealed hyperintensities of symmetrical periventricular, subcortical, centrum semiovale and corona radiata regions on T2 and FLAIR weighted images. He developed seizures and showed developmental regression at he age of 3,5 years. Beside, coarse facial features and hepatomegaly were detected on phsyical examination. Lysosomal enzyme analysis revelaed alfa fucosidase deficiency and molecular genetic analysis identified a novel homozygous pathogenic p. Lys431 fs variant in FUCA1 gene. CONCLUSIONS: In Turkish patients no distinguishable clinical and radiologic finding could be established. Molecular analysis was performed in few patients. Increasing of molecular and biochemical facilities might enable to make diagnosis and increase the prevalence of the disease in countries with high rate of consanguineous marriages. Moreover, it will provide genetic counseling, and enlighten the therapeutic effects of hematopoietic stem cell transplantation.

Novel Dominant-Negative GH Receptor Mutations Expands the Spectrum of GHI and IGF-I Deficiency.

CONTEXT: Autosomal-recessive mutations in the growth hormone receptor (GHR) are the most common causes for primary growth hormone insensitivity (GHI) syndrome with classical GHI phenotypically characterized by severe short stature and marked insulin-like growth factor (IGF)-I deficiency. We report three families with dominant-negative heterozygous mutations in the intracellular domain of the GHR causing a nonclassical GHI phenotype. OBJECTIVE: To determine if the identified GHR heterozygous variants exert potential dominant-negative effects and are the cause for the GHI phenotype in our patients. RESULTS: All three mutations (c.964dupG, c.920_921insTCTCAAAGATTACA, and c.945+2T>C) are predicted to result in frameshift and early protein termination. In vitro functional analysis of variants c.964dupG and c.920_921insTCTCAAAGATTACA (c.920_921ins14) suggests that these variants are expressed as truncated proteins and, when coexpressed with wild-type GHR, mimicking the heterozygous state in our patients, exert dominant-negative effects. Additionally, we provide evidence that a combination therapy of recombinant human growth hormone (rhGH) and rhIGF-I improved linear growth to within normal range for one of our previously reported patients with a characterized, dominant-negative GHR (c.899dupC) mutation. CONCLUSION: Dominant-negative GHR mutations are causal of the mild GHI with substantial growth failure observed in our patients. Heterozygous defects in the intracellular domain of GHR should, therefore, be considered in cases of idiopathic short stature and IGF-I deficiency. Combination therapy of rhGH and rhIGF-I improved growth in one of our patients.

Evaluation of risk factors for development of severe hyperbilirubinemia in term and near term infants in Turkey.

OBJECTIVE: To determine clinical features, etiology and risk factors in term and near term newborns with severe hyperbilirubinemia. METHODS: During ten years period (2000 - 2009), infants of ≥ 35 gestational weeks who received phototherapy were evaluated retrospectively. The study population was divided into two groups and clinical features, etiology and risk factors were compared. Group 1 defined by those who had bilirubin level ≥25 mg/dl (severe hyperbilirubinemia) and group 2 defined by bilirubin level <25 mg/dl. RESULTS: During the study period 1335 babies were evaluated. Severe hyperbilirubinemia was found in 137 (10.3%) patients. Total serum bilirubin level was 29.7±4.7 mg/dl in group 1 and 18.9±3.5 mg/dl in group 2. Pathological weight loss, vaginal delivery and supplementary feeding were identified as significant risk factors for development of severe hyperbilirubinemia (p <0.001, p <0.001 and p = 0.04, respectively). The time at recognition of jaundice by family and postnatal age at admission were significantly higher in group 1. The ratios of previous sibling received phototherapy and being the second child or after were found higher in group 1. CONCLUSION: Pathological weight loss, vaginal delivery and supplementary feeding were determined as risk factors for development of severe hyperbilirubinemia. The newborns with severe hyperbilirubinemia had late recognition of jaundice and admission to hospital by their families.