Pediatric management challenges of hyperglycemic hyperosmolar state: case series of Korean adolescents with type 2 diabetes

The hyperglycemic hyperosmolar state (HHS) is considered the most fatal complication of type 2 diabetes mellitus (DM). The number of case reports describing pediatric HHS has increased recently in parallel with obesity and the prevalence of type 2 DM in pediatric patients. In this study, we investigated the patient characteristics and outcomes of HHS in 9 adolescents with obesity and type 2 DM. Almost all patients exhibited mixed clinical features of HHS and diabetic ketoacidosis (DKA), including characteristics such as hyperosmolality and ketoacidosis. These features made definitive diagnosis difficult; 5 out of 9 patients were initially diagnosed with DKA and were treated accordingly. Patients who were initially diagnosed with HHS received a more vigorous and appropriate fluid replacement than other patients did. No patients died, although 3 exhibited complications, such as arrhythmia, acute kidney injury requiring renal replacement therapy, rhabdomyolysis, and acute pancreatitis. Hyperosmolality with consequent severe dehydration is considered a significant factor contributing to the outcomes of patients with HHS. Therefore, early recognition of hyperosmolality is crucial for an appropriate diagnosis and adequate fluid rehydration to restore perfusion in the early period of treatment to improve patient outcomes for this rare but serious emerging condition in pediatric patients.

The first case of novel variants of the FSHR mutation causing primary amenorrhea in 2 siblings in Korea

Follicle-stimulating hormone receptor (FSHR) mutation is a rare cause of amenorrhea. We report the first case of FSHR mutations in Korea. Two female siblings, aged 16 (patient 1) and 19 (patient 2) years, were referred to the pediatric endocrinology clinic because of primary amenorrhea despite normal breast budding. Gonadotropin-releasing hormone stimulation test showed markedly elevated luteinizing hormone and follicle-stimulating hormone with a relatively low level of estrogen, suggesting hypergonadotropic hypogonadism. Pelvic magnetic resonance imaging revealed a bicornuate uterus in patient 1 and uterine hypoplasia with thinning of the endometrium in patient 2. The progesterone challenge test revealed no withdrawal of bleeding. After two months of administration of combined oral contraceptives, menarche was initiated at regular intervals. To determine the genetic cause of amenorrhea in these patients, whole exome sequencing (WES) was performed, which revealed a compound heterozygous FSHR mutation, c.1364T>G (p.Val455Gly) on exon 10, and c.374T>G (p.Leu125Arg) on exon 4; both of which were novel mutations and were confirmed by Sanger sequencing. The patients maintained regular menstruation and improved bone mineral density while taking combined oral contraceptives, calcium, and vitamin D. Therefore, FSHR mutations can be the cause of amenorrhea in Koreans, and WES facilitates diagnosing the rare cause of amenorrhea.

From diagnosis to treatment of mucopolysaccharidosis type VI: A case report with a novel variant, c.1157C>T (p.Ser386Phe), in ARSB gene

Mucopolysaccharidosis type VI (MPS VI) is an autosomal recessive lysosomal disorder caused by the deficiency of arylsulfatase B due to mutations in the ARSB gene. Here, we report the case of a Korean female with a novel variant of MPS VI.A Korean female aged 5 years and 8 months, who is the only child of a healthy non-consanguineous Korean couple, presented at our hospital for severe short stature. She had a medical history of umbilical hernia and recurrent otitis media. Her symptoms included snoring and mouth breathing. Subtle dysmorphic features, including mild coarse face, joint contracture, hepatomegaly, and limited range of joint motion, were identified. Radiography revealed deformities, suggesting skeletal dysplasia. Growth hormone (GH) provocation tests revealed complete GH deficiency. Targeted exome sequencing revealed compound heterozygous mutations in the ARSB genes c.512G>A (p.Gly171Asp; a pathogenic variant inherited from her father) and c.1157C>T (p.Ser386Phe; a novel variant inherited from her mother in familial genetic testing). Quantitative tests revealed increased urine glycosaminoglycan (GAG) levels and decreased enzyme activity of arylsulfatase B. While on enzyme replacement therapy and GH therapy, her height increased drastically; her coarse face, joint contracture, snoring, and obstructive sleep apnea improved; urine GAG decreased; and left ventricular mass index was remarkably decreased. We report a novel variant—c.1157C>T (p.Ser386Phe)—of the ARSB gene in a patient with MPS VI; these findings will expand our knowledge of its clinical spectrum and molecular mechanisms.

Prospective evaluation of the clinical utility of whole-exome sequencing using buccal swabbing for undiagnosed rare diseases

Purpose@#Whole-exome sequencing (WES) has been a useful tool for novel gene discovery of various disease categories, further increasing the diagnostic yield. This study aimed to investigate the clinical utility of WES prospectively in undiagnosed genetic diseases. @*Materials and Methods@#WES tests were performed on 110 patients (age range, 0-28 years) with suspected rare genetic diseases. WES tests were performed at a single reference laboratory and the variants reported were reviewed by clinical geneticists, pediatricians, neurologists, and laboratory physicians. @*Results@#The patients’ symptoms varied with abnormalities in the head or neck, including facial dysmorphism, being the most common, identified in 85.4% of patients, followed by abnormalities in the nervous system (83.6%). The average number of systems manifesting phenotypic abnormalities per patient was 3.9±1.7. The age at presentation was 2.1±2.7 years old (range, 0-15 years), and the age at WES testing was 6.7±5.3 years (range, 0-28 years). In total, WES test reported 100 pathogenic/likely pathogenic variants or variants of uncertain significance for 79 out of 110 probands (71.8%). Of the 79 patients with positive or inconclusive calls, 55 (50.0%) patients were determined to have good genotype-phenotype correlations after careful review. Further clinical reassessment and family member testing determined 45 (40.9%) patients to have been identified with a molecular diagnosis. @*Conclusion@#This study showed a 40.9% diagnostic yield for WES test for a heterogeneous patient cohort with suspected rare genetic diseases. WES could be the feasible genetic test modality to overcome the diversity and complexity of rare disease diagnostics.

Response to growth hormone according to provocation test results in idiopathic short stature and idiopathic growth hormone deficiency

Purpose@#To investigate growth response in children with either idiopathic short stature (ISS) or growth hormone (GH) deficiency (GHD). @*Methods@#The data of prepubertal GHD or ISS children treated using recombinant human GH were obtained from the LG Growth Study database. GHD children were further divided into partial and complete GHD groups. Growth response and factors predicting growth response after 1 and 2 years of GH treatment were investigated. @*Results@#This study included 692 children (98 with ISS, 443 partial GHD, and 151 complete GHD). After 1 year, changes in height standard deviation score (ΔHt-SDS) were 0.78, 0.83, and 0.96 in ISS, partial GHD, and complete GHD, respectively. Height velocity (HV) was 8.72, 9.04, and 9.52 cm/yr in ISS, partial GHD, and complete GHD, respectively. ΔHt-SDS and HV did not differ among the 3 groups. Higher initial body mass index standard deviation score (BMI-SDS) and midparental height standard deviation score (MPH-SDS) were predictors for better growth response after 1 year in ISS and the partial GHD group, respectively. In the complete GHD group, higher Ht-SDS and BMI-SDS predicted better growth response after 1 year. After 2 years of GH treatment, higher BMI-SDS and MPH-SDS predicted a better growth outcome in the partial GHD group, and higher MPH-SDS was a predictor of good growth response in complete GHD. @*Conclusion@#Clinical characteristics and growth response did not differ among groups. Predictors of growth response differed among the 3 groups, and even in the same group, a higher GH dose would be required when poor response is predicted.

Fabry nephropathy before and after enzyme replacement therapy: important role of renal biopsy in patients with Fabry disease

Background@#In Fabry disease, the presence of globotriaosylceramide (GL3) deposits in various kidney cells leads to progressive renal dysfunction. However, kidney biopsy studies in patients with Fabry disease are limited. In the present study, the pathologic findings of patients with Fabry nephropathy receiving enzyme replacement therapy (ERT) and untreated patients without albuminuria were investigated. @*Methods@#The present study included 15 patients with Fabry disease who underwent renal biopsy while receiving ERT (group 1: n = 9, age 19–58 years, two males and seven females) or before ERT initiation (group 2: n = 6, age 11–66 years, one male and five females). All patients in group 2 were normoalbuminuric. @*Results@#Group 1 showed improved clinical symptoms, such as acroparesthesia. The ERT duration was 1.2 to 8 years and seven of the nine patients showed GL3 deposits in various kidney cells and segmental foot process effacement (FPE) of podocytes. GL3 deposits and FPE were not observed in the two remaining patients in group 1. Group 2 showed segmental FPE and podocyte GL3 deposits. Most patients in group 2 also showed GL3 deposits in the mesangium, endothelium, or tubular epithelium. @*Conclusion@#The study results showed that segmental FPE and GL3 deposits can persist in Fabry nephropathy despite ERT. In addition, segmental FPE and GL3 deposits were observed in various kidney cells in normoalbuminuric patients with Fabry disease. These findings indicated that kidney biopsies at baseline and follow-up evaluation of Fabry nephropathy are essential for timely ERT initiation and ERT response assessment.

Successful rapid weight reduction and the use of liraglutide for morbid obesity in adolescent Prader-Willi syndrome

Prader-Willi syndrome (PWS), an imprinting disorder, results from the loss of expression of a paternal gene on chromosome 15q11-q13. Progressive obesity and its associated complications lead to increased morbidity and early death in PWS patients. The management techniques available for morbid obesity in adolescents and adults with PWS are limited. Herein, we report successful weight reduction in an adolescent PWS case showing morbid obesity and respiratory failure. An 18-year-old girl with PWS presented with diffuse cellulitis and dyspnea due to severe obesity. Her body weight had increased from 146 to 161 kg despite dietary restriction to 800 kcal/day, and a mechanical ventilator was required for dyspnea. During mechanical ventilation, the patient was managed using diuretics and by restricting fluid intake; her daily calorie intake was reduced to 200 kcal. This aggressive calorie and water restriction continued for 3 weeks and reduced her body weight to 118.6 kg. After transfer to the general ward, the patient was provided with growth hormone therapy and intensive aquatic rehabilitation and was administered liraglutide; as a result, her weight further decreased to 104 kg (body mass index [BMI], 50.8 kg/m2), and she was discharged. Following discharge, she maintained her BMI and adapted to 1,000 kcal/day for 1 year. Aggressive water and calorie restriction were observed as an effective method for rapid weight reduction in PWS patients, and liraglutide appeared useful in maintaining weight reduction in adolescent and adult PWS.

Clinical, endocrinological, and molecular features of four Korean cases of cytochrome P450 oxidoreductase deficiency

Purpose@#Cytochrome P450 oxidoreductase (POR) deficiency is a rare autosomal recessive disorder caused by mutations in the POR gene encoding an electron donor for all microsomal P450 enzymes. It is characterized by adrenal insufficiency, ambiguous genitalia, maternal virilization during pregnancy, and skeletal dysplasia. In this study, we investigated the clinical, hormonal, and molecular characteristics of patients with POR deficiency in Korea. @*Methods@#This study included four patients with POR deficiency confirmed by biochemical and molecular analysis of POR. Clinical and biochemical findings were reviewed retrospectively. Mutation analysis of POR was performed by Sanger sequencing after polymerase chain reaction amplification of all coding exons and the exon-intron boundaries. @*Results@#All patients presented with adrenal insufficiency and ambiguous genitalia regardless of their genetic sex. Two patients harbored homozygous p.R457H mutations in POR and presented with adrenal insufficiency and genital ambiguity without skeletal phenotypes. The other two patients with compound heterozygous mutations of c.[1329_1330insC];[1370G>A] (p.[I444Hfs*6];[R457H]) manifested skeletal abnormalities, such as craniosynostosis and radiohumeral synostosis, suggesting Antley-Bixler syndrome. They also had multiple congenital anomalies involving heart, kidney, and hearing ability. All patients were treated with physiologic doses of oral hydrocortisone. @*Conclusion@#We report the cases of 4 patients with POR deficiency identified by mutation analysis of POR. Although the study involved a small number of patients, the POR p.R457H mutation was the most common, suggesting founder effect in Korea. POR deficiency is rare and can be misdiagnosed as 21-hydroxylase or 17α-hydroxylase/17,20-lyase deficiency. Therefore, molecular analysis is critical for confirmatory diagnosis.

Evaluation and management of amenorrhea related to congenital sex hormonal disorders

Primary amenorrhea is a symptom with a substantial list of underlying etiologies which presents in adolescence, although some conditions are diagnosed in childhood. Primary amenorrhea is defined as not having menarche until 15 years of age (or 13 years with secondary sex characteristics). Various etiologies of primary amenorrhea include outflow tract obstructions, gonadal dysgenesis, abnormalities of the central nervous system, various endocrine diseases, chronic illnesses, psychologic problems, and constitutional delay of puberty. The management of primary amenorrhea may vary considerably depending on the patient and the specific diagnosis. In this article, the various causes, evaluation, and management of primary amenorrhea are reviewed with special emphasis on congenital sex hormonal disorders.

Comparison of effectiveness of growth hormone therapy according to disease-causing genes in children with Noonan syndrome / 소아과

PURPOSE: To analyze the growth response to growth hormone (GH) therapy in prepubertal patients with Noonan syndrome (NS) harboring different genetic mutations. METHODS: Twenty-three patients with prepubertal NS treated at Pusan National University Children’s Hospital between March 2009 and July 2017 were enrolled. According to the disease-causing genes identified, the patients with NS were divided into 4 groups. Three groups were positive for mutations of the PTPN11, RAF1, and SOS1 genes. The five genes undetected (FGU) group was negative for PTPN11, RAF1, SOS1, KRAS, and BRAF gene mutations. The influence of genotype was retrospectively analyzed by comparing the growth parameters after GH therapy. RESULTS: The mean chronological age at the start of GH treatment was 5.85±2.67 years. At the beginning of the GH treatment, the height standard deviation score (SDS), growth velocity (GV), and lower levels of insulin-like growth factor-1 (IGF)-1 levels were not statistically different among the groups. All the 23 NS patients had significantly increased height SDS and serum IGF-1 level during the 3 years of treatment. GV was highest during the first year of treatment. During the 3 years of GH therapy, the PTPN11, RAF1, and SOS1 groups showed less improvement in height SDS, IGF-1 SDS, and GV, and less increase in bone age-to-chronological age ratio than the FGU group. CONCLUSION: The 3-year GH therapy in the 23 prepubertal patients with NS was effective in improving height SDS, GV, and serum IGF-1 levels. The FGU group showed a better response to recombinant human GH therapy than the PTPN11, RAF1, and SOS1 groups.

A Rare Cause of Life-Threatening Ketoacidosis: Novel Compound Heterozygous OXCT1 Mutations Causing Succinyl-CoA:3-Ketoacid CoA Transferase Deficiency

Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency is a rare inborn error of ketone body utilization, characterized by episodic or permanent ketosis. SCOT deficiency is caused by mutations in the OXCT1 gene, which is mapped to 5p13 and consists of 17 exons. A 12-month-old girl presented with severe ketoacidosis and was treated with continuous renal replacement therapy. She had two previously unrecognized mild-form episodes of ketoacidosis followed by febrile illness. While high levels of ketone bodies were found in her blood and urine, other laboratory investigations, including serum glucose, were unremarkable. We identified novel compound heterozygous mutations in OXCT1:c.1118T>G (p.Ile373Ser) and a large deletion ranging from exon 8 to 16 through targeted exome sequencing and microarray analysis. This is the first Korean case of SCOT deficiency caused by novel mutations in OXCT1, resulting in life-threatening ketoacidosis. In patients with unexplained episodic ketosis, or high anion gap metabolic acidosis in infancy, an inherited disorder in ketone body metabolism should be suspected.

Genetic overgrowth syndrome: A single center's experience

PURPOSE: Overgrowth syndromes are conditions that involve generalized or localized areas of excess growth. In this study, the clinical, molecular, and genetic characteristics of Korean patients with overgrowth syndrome were analyzed. MATERIALS AND METHODS: We recruited 13 patients who presented with overgrowth syndrome. All patients fulfilled inclusion criteria of overgrowth syndrome. Analysis of the clinical and molecular investigations of patients with overgrowth syndrome was performed retrospectively. RESULTS: Among the 13 patients with overgrowth syndrome, 9 patients (69.2%) were found to have molecular and genetic causes. Among the seven patients with Sotos syndrome (SS), two had a 5q35microdeletion that was confirmed by fluorescent in situ hybridization. In two patients with SS, intragenic mutations including a novel mutation, c.5993T>A (p.M1998L), were found by Sanger sequencing. One patient had one copy deletion of NDS1 gene which was confirmed by multiplex ligation-dependent probe amplification. Among five patients with Beckwith-Wiedemann syndrome, three had aberrant imprinting control regions; 2 hypermethylation of the differentially methylated region of H19, 1 hypomethylation of the differentially methylated region of Kv. In one patient displaying overlapping clinical features of SS, a de novo heterozygous deletion in the chromosomal region 7q22.1-22.3 was found by single nucleotide polymorphism-based microarray. CONCLUSION: Considering high detection rate of molecular and genetic abnormalities in this study, rigorous investigations of overgrowth syndrome may be an important tool for the early diagnosis and genetic counseling. A detailed molecular analysis of the rearranged regions may supply the clues for the identification of genes involved in growth regulation.

Identification of a novel heterozygous mutation of ACAN in a Korean family with proportionate short stature

Aggrecan is a proteoglycan in the extracellular matrix of growth plate and cartilaginous tissues. Aggrecanopathy has been reported as a genetic cause not only for severe skeletal dysplasia but also for autosomal dominant short stature with normal to advanced bone age. We report a novel heterozygous mutation of ACAN in a Korean family with proportionate short stature identified through targeted exome sequencing. We present a girl of 4 years and 9 months with a family history of short stature over three generations. The paternal grandmother is 143 cm tall (−3.8 as a Korean standard deviation score [SDS]), the father 155 cm (−3.4 SDS), and the index case 96.2 cm (−2.9 SDS). Evaluation for short stature showed normal growth hormone (GH) peaks in the GH provocation test and a mild delayed bone age for chronological age. This subject had clinical characteristics including a triangular face, flat nasal bridge, prognathia, blue sclerae, and brittle teeth. The targeted exome sequencing was applied to detect autosomal dominant growth palate disorder. The novel variant c.910G>A (p.Asp304Asn) in ACAN was identified and this variant was found in the subject's father using Sanger sequencing. This is the first case of Korean familial short stature due to ACAN mutation. ACAN should be considered for proportionate idiopathic short stature, especially in cases of familial short stature.

Understanding of type 1 diabetes mellitus: what we know and where we go / 소아과

The incidence of type 1 diabetes mellitus (T1DM) in children and adolescents is increasing worldwide. Combined effects of genetic and environmental factors cause T1DM, which make it difficult to predict whether an individual will inherit the disease. Due to the level of self-care necessary in T1DM maintenance, it is crucial for pediatric settings to support achieving optimal glucose control, especially when adolescents are beginning to take more responsibility for their own health. Innovative insulin delivery systems, such as continuous subcutaneous insulin infusion (CSII), and noninvasive glucose monitoring systems, such as continuous glucose monitoring (CGM), allow patients with T1DM to achieve a normal and flexible lifestyle. However, there are still challenges in achieving optimal glucose control despite advanced technology in T1DM administration. In this article, disease prediction and current management of T1DM are reviewed with special emphasis on biomarkers of pancreatic β-cell stress, CSII, glucose monitoring, and several other adjunctive therapies.

The First Korean case of combined oxidative phosphorylation deficiency-17 diagnosed by clinical and molecular investigation / 소아과

Combined oxidative phosphorylation deficiency-17 (COXPD-17) is very rare and is caused by homozygous or compound heterozygous mutations in the ELAC2 gene on chromosome 17p12. The ELAC2 gene functions as a mitochondrial tRNA processing gene, and only 4 different pathogenic mutations have been reported in ELAC2-associated mitochondrial dysfunction involving oxidative phosphorylation. Affected patients show various clinical symptoms and prognosis, depending on the genotype. We report a novel mutation in the ELAC2 gene (c.95C>G [p.Pro32Arg], het), in an infant with COXPD-17 who presented with encephalopathy including central apnea and intractable epilepsy, and growth and developmental retardation. During hospitalization, consistently elevated serum lactic acid levels were noted, indicative of mitochondrial dysfunction. The patient suddenly died of shock of unknown cause at 5 months of age. This is the first case report of COXPD-17 in Korea and was diagnosed based on clinical characteristics and genetic analysis.

Association of Obesity or Overweight with Bone Health in Childhood and Adolescence: Another Health Risk Never to Be Underestimated

No abstract available.

Identification of a novel frameshift mutation (L345Sfs*15) in a Korean neonate with methylmalonic acidemia

Methylmalonic acidemia (MMA) is an autosomal recessive metabolic disorder characterized by an abnormal accumulation of methylmalonyl-CoA and methylmalonate in body fluids without hyperhomocysteinemia. Cardiac disease is a rarely known lethal complication of MMA, herein, we report a Korean neonate diagnosed with MMA on the basis of biochemical and genetic findings, who developed cardiomyopathy, resulting in sudden death. The patient presented vomiting and lethargy at 3 days of age. Initially, the patient had an increased plasma propionylcarnitine/acetylcarnitine concentration ratio of 0.49 in a tandem mass spectrometry analysis and an elevated ammonia level of 537 µmol/L. Urine organic acid analysis showed increased excretion of methylmalonate. Subsequent sequence analysis of the methylmalonyl-CoA mutase (MUT) gene revealed compound heterozygous mutations c.323G>A (p.Arg108His) in exon 1 and c.1033_1034del (p. Leu345Serfs*15) in exon 4, the latter being a novel mutation. In summary, this is the first case of MMA and cardiomyopathy in Korea that was confirmed by genetic analysis to involve a novel MUT mutation.

Ocular Findings in Mucolipidosis Type II

PURPOSE: To report ocular findings of a mucolipidosis type II patient with novel mutation. CASE SUMMARY: A 10-year-old boy visited our pediatric genetic metabolic clinic for evaluation of his overall developmental delay and short stature. The boy was diagnosed with mucolipidosis type II (I-cell disease) using plasma enzyme assay and DNA sequencing of the GNPTAB gene mutation. An ophthalmologic investigation was then performed, and a depressed nasal bridge, broad nose, and swelling in the upper lid of both eyes were noted. The best corrected visual acuity was 0.32 and 0.1 and the intraocular pressure was 35 mmHg and 24 mmHg in the right and left eyes, respectively. The anterior chamber angles of both eyes were normal and mild cornea opacity in both eyes was observed. Fundus examination revealed retinal atrophy with folds in both eyes, as well as optic disc edema and optic atrophy in the right and left eyes, respectively. Atherosclerotic changes in the retinal vessels and cystoid macular edema in the left eye were observed, and ocular ultrasound revealed increased posterior sclera thickness in both eyes. CONCLUSIONS: Ocular manifestations of mucolipidosis type II are not currently well-known, and differentiation from other metabolic disorders may be difficult. An ophthalmic work-up can assist in diagnosis, and regular ophthalmic examinations should be used to maintain visual function in mucolipidosis patients.

A rare case of multiple pituitary adenomas in an adolescent Cushing disease presenting as a vertebral compression fracture

Cushing disease in children and adolescents, especially with multiple pituitary adenomas (MPAs), is very rare. We report 17-year-old boy with MPAs. He presented with a vertebral compression fracture, weight gain, short stature, headache, and hypertension. On magnetic resonance imaging (MRI), only a left pituitary microadenoma was found. After surgery, transient clinical improvement was observed but headache and hypertension were observed again after 3 months later. Follow-up MRI showed a newly developed right pituitary microadenoma 6 months after the surgery. The need for careful clinical and radiographic follow-up should be emphasized in the search for potential MPAs in patients with persistent Cushing disease.

Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome

The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.