Gu Hwan Kim

Clinical and genetic characteristics of Gaucher disease according to phenotypic subgroups

Purpose Gaucher disease is caused by a β-glucocerebrosidase (GBA) deficiency. The aim of this study is to investigate the clinical and genetic characteristics according to subtypes of Gaucher disease in the Korean population. Methods Clinical findings at diagnosis, GBA mutations, and clinical courses were reviewed in 20 patients diagnosed with Gaucher disease. Results Eleven patients were diagnosed with non-neuronopathic type, 2 with acute neuronopathic type, and 7 with chronic neuronopathic type. Most patients presented with hepatosplenomegaly, thrombocytopenia, and short stature. In the neuronopathic group, variable neurological features, such as seizure, tremor, gaze palsy, and hypotonia, were noted at age 8.7±4.3 years. B cell lymphoma, protein-losing enteropathy, and hydrops fetalis were the atypical manifestations. Biomarkers, including chitotriosidase, acid phosphatase, and angiotensin-converting enzyme, increased at the initial evaluation and subsequently decreased with enzyme replacement treatment (ERT). The clinical findings, including hepatosplenomegaly, thrombocytopenia, and skeletal findings, improved following ERT, except for the neurological manifestations. L444P was the most common mutation in our cohort. One novel mutation, R277C, was found. Conclusion Although the clinical outcome for Gaucher disease improved remarkably following ERT, the outcome differed according to subtype. Considering the high proportion of the neuronopathic form in the Korean population, new therapeutic strategies targeting the central nervous system are needed, with the development of a new scoring system and biomarkers representing clinical courses in a more comprehensive manner.

Epilepsy and Other Neuropsychiatric Manifestations in Children and Adolescents with 22q11.2 Deletion Syndrome

Background and Purpose 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion syndrome. Epilepsy and other neuropsychiatric (NP) manifestations of this genetic syndrome are not uncommon, but they are also not well-understood. We sought to identify the characteristics of epilepsy and other associated NP manifestations in patients with 22q11.2DS. Methods We retrospectively analyzed the medical records of 145 child and adolescent patients (72 males and 73 females) with genetically diagnosed 22q11.2DS. The clinical data included seizures, growth chart, psychological reports, development characteristics, school performance, other clinical manifestations, and laboratory findings. Results Of the 145 patients with 22q11.2DS, 22 (15.2%) had epileptic seizures, 15 (10.3%) had developmental delay, and 5 (3.4%) had a psychiatric illness. Twelve patients with epilepsy were classified as genetic epilepsy whereas the remaining were classified as structural, including three with malformations of cortical development. Patients with epilepsy were more likely to display developmental delay (odds ratio=3.98; 95% confidence interval=1.5-10.5; p=0.005), and developmental delay was more common in patients with structural epilepsy than in those with genetic epilepsy. Conclusions Patients with 22q11.2DS have a high risk of epilepsy, which in these cases is closely related to other NP manifestations. This implies that this specific genetic locus is critically linked to neurodevelopment and epileptogenesis.

Clinical, endocrinological, and molecular characterization of Kallmann syndrome and normosmic idiopathic hypogonadotropic hypogonadism: a single center experience

Purpose Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is classified as Kallmann syndrome (KS) with anosmia and normosmic idiopathic hypogonadotropic hypogonadism (nIHH). This study was undertaken to investigate the clinical, endocrinological, and molecular characteristics in Korean patients with KS and nIHH. Methods Twenty-six patients from 25 unrelated families were included. Their clinical, endocrinological, and radiological findings were analyzed retrospectively. Mutation analysis of the GNRH1, GNRHR, KISS1, KISS1R, PROK2, PROKR2, TAC3, TACR3, FGF8, FGFR1, and KAL1 genes was performed in all patients. CHD7 and SOX10 were analyzed in patients with CHARGE (Coloboma, Heart defects, choanae Atresia, Growth retardation, Genitourinary abnormality, Ear abnormality) features or deafness. Results Of the 26 patients, 16 had KS and 10 had nIHH. At diagnosis, mean chronologic age was 18.1 years in males and 18.0 years in females; height SDS were -0.67±1.35 in males, -1.12±1.86 in females; testis volume was 2.0±1.3 mL; and Tanner stage was 1.5. There were associated anomalies in some of the KS patients: hearing loss (n=6) and congenital heart disease (n=4). Absence or hypoplasia of the olfactory bulb/sulci was found in 84.62% of patients with KS. Molecular defects in KAL1, SOX10, and CHD7 were identified in 5 patients from 4 families (16.0%, 4/25 pedigrees). After sex hormone replacement therapy, there were improvement in sexual characteristics and the sexual function. Conclusion This study described the clinical, endocrinological, and molecular genetic features in IGD patients in Korea. Although the mutation screening was performed in 10 genes that cause IGD, molecular defects were identified in relatively small proportions of the cohort.

Successful sulfonylurea treatment in a patient with permanent neonatal diabetes mellitus with a novel KCNJ11 mutation.

Permanent neonatal diabetes mellitus refers to diabetes that occurs before the age of 6 months and persists through life. It is a rare disorder affecting one in 0.2-0.5 million live births. Mutations in the gene KCNJ11, encoding the subunit Kir6.2, and ABCC8, encoding SUR1 of the ATP-sensitive potassium (KATP) channel, are the most common causes of permanent neonatal diabetes mellitus. Sulfonylureas close the KATP channel and increase insulin secretion. KCNJ11 and ABCC8 mutations have important therapeutic implications because sulfonylurea therapy can be effective in treating patients with mutations in the potassium channel subunits. The mutation type, the presence of neurological features, and the duration of diabetes are known to be the major factors affecting the treatment outcome after switching to sulfonylurea therapy. More than 30 mutations in the KCNJ11 gene have been identified. Here, we present our experience with a patient carrying a novel p.H186D heterozygous mutation in the KCNJ11 gene who was successfully treated with oral sulfonylurea.

Testicular adrenal rest tumors in a patient with untreated congenital adrenal hyperplasia

Testicular adrenal rest tumors (TARTs) are considered to be formed from aberrant adrenal tissue that has become hyperplastic because of elevated adrenocorticotropic hormone (ACTH) in male patients with congenital adrenal hyperplasia (CAH). A 6-year-old boy presented with testicular enlargement and pubic hair. He was diagnosed with CAH complicated by precocious puberty. However, he was not followed-up. At the age of 17, he visited the outpatient clinic because of testicular enlargement and short stature. His right and left testicles were 10×6 cm and 7.5×4.5 cm, respectively. His height was 155.1 cm (standard deviation score [SDS], -2.90). The diagnosis of CAH due to 21 hydroxylase deficiency was confirmed by mutation analysis of CYP21A2. Histological examination of the testes showed large, polygonal, eosinophilic cells with round nuclei and prominent nucleoli, which were suggestive of TARTs. He was treated with dexamethasone for 3 weeks and tumors regressed. Subsequently, dexamethasone was replaced by prednisolone and 9α-fludrocortisone; thereafter, the reduced testis size has been maintained.

Recent advances in biochemical and molecular analysis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

The term congenital adrenal hyperplasia (CAH) covers a group of autosomal recessive disorders caused by defects in one of the steroidogenic enzymes involved in the synthesis of cortisol or aldosterone from cholesterol in the adrenal glands. Approximately 95% of all CAH cases are caused by 21-hydroxylase deficiency encoded by the CYP21A2 gene. The disorder is categorized into classical forms, including the salt-wasting and the simple virilizing types, and nonclassical forms based on the severity of the disease. The severity of the clinical features varies according to the level of residual 21-hydroxylase activity. Newborn screening for CAH is performed in many countries to prevent salt-wasting crises in the neonatal period, to prevent male sex assignment in affected females, and to reduce long-term morbidities, such as short stature, gender confusion, and psychosexual disturbances. 17α-hydroxyprogesterone is a marker for 21-hydroxylase deficiency and is measured using a radioimmunoassay, an enzyme-linked immunosorbent assay, or a fluoroimmunoassay. Recently, liquid chromatography linked with tandem mass spectrometry was developed for rapid, highly specific, and sensitive analysis of multiple analytes. Urinary steroid analysis by gas chromatography mass spectrometry also provides qualitative and quantitative data on the excretion of steroid hormone metabolites. Molecular analysis of CYP21A2 is useful for genetic counseling, confirming diagnosis, and predicting prognoses. In conclusion, early detection using neonatal screening tests and treatment can prevent the worst outcomes of 21-hydroxylase deficiency.

Two cases of chronic pancreatitis associated with anomalous pancreaticobiliary ductal union and SPINK1 mutation

Chronic pancreatitis is a progressive inflammatory disease resulting from repeated episodes of acute pancreatitis that impair exocrine function and eventually produce endocrine insufficiency. Some causes of chronic pancreatitis appear to be associated with alterations in the serine-protease inhibitor, Kazal type 1 (SPINK1), cationic trypsinogen (PRSS1), and cystic fibrosis-transmembrane conductance regulator (CFTR) genes, or with structural disorders in the pancreaticobiliary ductal system, such as pancreatic divisum or anomalous pancreaticobiliary ductal union (APBDU). However, it is unusual to observe both genetic alteration and structural anomaly. Here, we report 2 cases with both APBDU and a mutation in the SPINK1 genes, and we discuss the implications of these findings in clinical practice.

A Novel Frameshift Mutation of the ALDOB Gene in a Korean Girl Presenting with Recurrent Hepatitis Diagnosed as Hereditary Fructose Intolerance

Hereditary fructose intolerance is an autosomal recessive disorder that is caused by a deficiency in fructose-1-phosphate aldolase (Aldolase B). Children can present with hypoglycemia, jaundice, elevated liver enzymes and hepatomegaly after intake of dietary fructose. Long-term intake of fructose in undiagnosed patients can result in hepatic failure or renal failure. We experienced a case of hereditary fructose intolerance presenting as recurrent hepatitis-like episodes. Detailed evaluation of her dietary habits revealed her avoidance of sweetened foods and fruits. Genetic analysis of ALDOB revealed that she is a homozygote for a novel frameshifting mutation c[758_759insT]+[758_759insT] (p.[val25 3fsX24]+[val253fsX24]). This report is the first of a Korean patient diagnosed with hereditary fructose intolerance using only molecular testing without undergoing intravenous fructose tolerance test or enzyme assay.

Identification of 1p36 deletion syndrome in patients with facial dysmorphism and developmental delay

Purpose The 1p36 deletion syndrome is a microdeletion syndrome characterized by developmental delays/intellectual disability, craniofacial dysmorphism, and other congenital anomalies. To date, many cases of this syndrome have been reported worldwide. However, cases with this syndrome have not been reported in Korean populations anywhere. This study was performed to report the clinical and molecular characteristics of five Korean patients with the 1p36 deletion syndrome. Methods The clinical characteristics of the 5 patients were reviewed. Karyotyping and multiplex ligation-dependent probe amplification (MLPA) analyses were performed for genetic diagnoses. Results All 5 patients had typical dysmorphic features including frontal bossing, flat right parietal bone, low-set ears, straight eyebrows, down-slanting palpebral fissure, hypotelorism, flat nasal roots, midface hypoplasia, pointed chins, small lips, and variable degrees of developmental delay. Each patient had multiple and variable anomalies such as a congenital heart defect including ventricular septal defect, atrial septal defect, and patent duct arteriosus, ventriculomegaly, cryptorchism, or hearing loss. Karyotyping revealed the 1p36 deletion in only 1 patient, although it was confirmed in all 5 patients by MLPA analyses. Conclusion All the patients had the typical features of 1p36 deletion. These hallmarks can be used to identify other patients with this condition in their early years in order to provide more appropriate care.

Maternal 3-methylcrotonyl-coenzyme A carboxylase deficiency with elevated 3-hydroxyisovalerylcarnitine in breast milk

We report here a case of maternal 3-methylcrotonyl-coenzyme A carboxylase (3-MCC) deficiency in a Korean woman. Her 2 infants had elevated 3-hydroxyisovalerylcarnitine (C5-OH) on a neonatal screening test by liquid chromatography-tandem mass spectrometry (LC-MS/MS), but normal results were found on urine organic acid analysis. The patient was subjected to serial testing and we confirmed a maternal 3-MCC deficiency by blood spot and breast milk spot test by LC-MS/MS, serum amino acid analysis, urine organic acid and molecular genetic analysis that found c.838G>T (p.Asp280Tyr) homozygous mutation within exon 9 of the MCCB gene. Especially, we confirmed marked higher levels of C5-OH on breast milk spot by LC-MS/MS, in the case of maternal 3-MCC deficiency vs. controls.