Haddad Syndrome: A case report in a Filipino infant

@#Haddad syndrome is a rare congenital disorder in which congenital central hypoventilation syndrome (CCHS) occurs with Hirschsprung’s disease. It is extremely rare with only more than 60 cases reported in the worldwide literature. We report on a Filipino newborn male infant who presented with signs and symptoms of progressive abdominal enlargement, bowel obstruction, and recurrent hypoventilation. The diagnosis of Haddad syndrome was made clinically and confirmed by sequence analysis of the PHOX2B gene which showed a 27repeat heterozygous expansion of the polyalanine-coding region. All CCHS patients require assisted ventilation especially during sleep to prevent lung atelectasis and other complications. An early diagnosis and confirmation by genetic testing is vital for proper management of affected patients.

Congenital central hypoventilation syndrome associated with Hirschsprung's Disease: case report and literature review / Síndrome de hipoventilação central congênita associada à doença de Hirschsprung: relato de caso e revisão de literatura

Abstract Objective: To report the case of a newborn with recurrent episodes of apnea, diagnosed with Congenital Central hypoventilation syndrome (CCHS) associated with Hirschsprung's disease (HD), configuring Haddad syndrome. Case description: Third child born at full-term to a non-consanguineous couple through normal delivery without complications, with appropriate weight and length for gestational age. Soon after birth he started to show bradypnea, bradycardia and cyanosis, being submitted to tracheal intubation and started empiric antibiotic therapy for suspected early neonatal sepsis. During hospitalization in the NICU, he showed difficulty to undergo extubation due to episodes of desaturation during sleep and wakefulness. He had recurrent episodes of hypoglycemia, hyperglycemia, metabolic acidosis, abdominal distension, leukocytosis, increase in C-reactive protein levels, with negative blood cultures and suspected inborn error of metabolism. At 2 months of age he was diagnosed with long-segment Hirschsprung's disease and was submitted to segment resection and colostomy through Hartmann's procedure. A genetic research was performed by polymerase chain reaction for CCHS screening, which showed the mutated allele of PHOX2B gene, confirming the diagnosis. Comments: This is a rare genetic, autosomal dominant disease, caused by mutation in PHOX2B gene, located in chromosome band 4p12, which results in autonomic nervous system dysfunction. CCHS can also occur with Hirschsprung's disease and tumors derived from the neural crest. There is a correlation between phenotype and genotype, as well as high intrafamilial phenotypic variability. In the neonatal period it can simulate cases of sepsis and inborn errors of metabolism.

Resumo Objetivo: Relatar caso de neonato com episódios de apneias recorrentes, diagnosticado com síndrome de hipoventilação central congênita (SHCC) associada à doença de Hirschsprung (DH), o que configurou síndrome de Haddad. Descrição do caso: Terceiro filho de casal não consanguíneo, nascido a termo, parto normal sem intercorrências, peso e comprimento adequados para idade gestacional. Logo após o nascimento apresentou bradipneia, bradicardia e cianose, foi submetido à intubação orotraqueal e iniciada antibioticoterapia empírica devido à suspeita de sepse neonatal precoce. Durante internação em UTI neonatal evoluiu com dificuldade de extubação devido a episódios de dessaturação durante sono e vigília. Apresentou quadros recorrentes de hipoglicemia, hiperglicemia, acidose metabólica, distensão abdominal, leucocitose, aumento de proteína C reativa, com hemoculturas negativas e suspeita de erro inato do metabolismo. Aos dois meses foi diagnosticada doença de Hirschsprung de segmento longo, foi submetido à ressecção do segmento e colostomia à Hartmann. Feita pesquisa genética por reação em cadeia da polimerase para pesquisa de SHCC, que evidenciou alelo mutado do gene PHOX2B e confirmou o diagnóstico. Comentários: Trata-se de doença genética rara, de herança autossômica dominante, causada por mutação no gene PHOX2B, localizado na banda cromossômica 4p12, que resulta em disfunção do sistema nervoso autônomo. A SHCC também pode cursar com doença de Hirschsprung e tumores derivados da crista neural. Há correlação entre fenótipo e genótipo, além de grande variabilidade fenotípica intrafamiliar. No período neonatal pode simular quadros de sepse e erros inatos do metabolismo.

Haddad Syndrome with a Germ-Line Mutation in the PHOX2B Gene in a Korean Neonate

Congenital central hypoventilation syndrome (CCHS) is a life-threatening disease that primarily manifests as sleep-associated respiratory insufficiency and a markedly impaired ventilatory response to hypercarbia and hypoxemia. Paired-like homeobox 2b (PHOX2B) gene mutations are known to cause CCHS. Almost all patients with CCHS are heterozygous for a poly-alanine expansion in PHOX2B. However, some patients have other germ-line abnormalities, including missense, nonsense and frame shift mutations. CCHS combined with Hirschsprung disease (Haddad syndrome) is extremely rare. Here, we report the case of a 1-day-old male neonate with recurrent apnea and bowel distension. Genetic analysis showed that he was heterozygous for a germ-line mutation in the PHOX2B gene. Only three cases of CCHS including two with Haddad syndrome confirmed by PHOX2B gene mutations have been reported in Korea. All of these cases have been heterozygous for a poly-alanine expansion mutation. This is the first report describing Haddad syndrome with a germ-line mutation in the PHOX2B gene in a Korean neonate.

Molecular genetics of congenital central hypoventilation syndrome and Haddad syndrome

Congenital central hypoventilation syndrome (CCHS) is a disorder of the autonomic nervous system characterized by a decreased response to hypercarbia. CCHS is frequently associated with congenital megacolon; the combination is called Haddad syndrome. CCHS is associated with dysfunction in respiratory features of the autonomic nervous system and with other disorders, including facial deformities, cardiovascular symptoms, and tumors. Patients with CCHS frequently have a mutation in the homeobox protein 2b (PHOX2B) gene. Most mutations involve heterozygous expansion of alanine repeats (GCN). Interestingly, a higher polyalanine repeat number is associated with a more severe clinical phenotype. To clarify the role of PHOX2B in disease pathogenesis, we introduce and review the clinical and molecular features of CCHS and Haddad syndrome.

Haddad Syndrome with PHOX2B Gene Mutation in a Korean Infant

Congenital central hypoventilation syndrome with Hirschsprung's disease, also known as Haddad syndrome, is an extremely rare disorder with variable symptoms. Recent studies described that congenital central hypoventilation syndrome had deep relation to the mutation of the PHOX2B gene in its diagnosis and phenotype. We report a newborn male infant with clinical manifestations of recurrent hypoventilation with hypercapnea and bowel obstruction. These clinical manifestations were compatible with congenital central hypoventilation syndrome and Hirschsprung's disease, and polyalanine 26 repeats in the PHOX2B gene supported the diagnosis of congenital central hypoventilation. We described a first case of Haddad syndrome in Korean and its clinical and genetic characteristics were discussed.

Haddad Syndrome with 27 Polyalanine Repeats in PHOX2B Gene in a Korean Infant / 대한주산의학회잡지

Haddad syndrome is an extremely rare disorder which combines congenital central hypoventilation syndrome (CCHS) and Hirschsprung's disease. Several reports have demonstrated that CCHS was related to mutation of the PHOX2B gene. We report here a newborn male infant with apnea and bowel obstruction. He has been diagnosed with combined congenital central hypoventilation syndrome and Hirschsprung's disease, and had 27 polyalanine repeats in the PHOX2B gene. Two cases of Haddad syndrome with identified PHOX2B gene mutation have been recently reported in Korea. Both of them had extended alleles containing 26 polyalanine repeats. It is known that increased number of polyalanine repeat mutations is associated with a more severe clinical phenotype. The baby reported here had 27 alanine repeats (i.e. one more than the previously reported cases in Korea) and ganglion cells could be found only in the distal 70 cm of his small bowel.

A Case of Haddad Syndrome / 대한소아소화기영양학회지

The combination of Congenital central hypoventilation syndrome with Hirschsprung's disease, also known as Haddad syndrome, belongs to the family of diseases now designated as Neurocristopathies. We have experienced a case of Haddad syndrome in a male infant who presented with repetitive abdominal distension, bilious vomiting, and sleep apnea. Following colon study and rectal biopsy disclosed the absence of the ganglion cell. And the infant could not be weaned from mechanical ventilation since birth because of the absence of effective, spontaneous respiration during sleep. As he was diagnosed as Haddad syndrome, tracheostomy and ileostomy were performed consecutively. At the age of 4 months, he was relatively healthy but remained ventilator-dependent. We report the first Korean case of Haddad syndrome with a brief review of the related literature.