HemoChat is an evidence-based AI medical search tool covering all major clinical domains, powered by 46,298 SNOMED-CT concepts, clinical guidelines, and live PubMed literature.

What medical domains does HemoChat cover?

HemoChat covers all major medical domains including cardiology, oncology, neurology, hematology, pulmonology, endocrinology, gastroenterology, psychiatry, nephrology, rheumatology, musculoskeletal, and more — with 46,298 SNOMED-CT concepts.

Is HemoChat a replacement for clinical judgment?

No. HemoChat is for clinical reference only and is not a substitute for professional medical judgment. Always consult qualified healthcare professionals for medical decisions.

What AI technology does HemoChat use?

HemoChat uses a hybrid GraphRAG + VectorRAG pipeline combining Neo4j knowledge graphs with FAISS vector search and an LLM for answer generation.

Alobar holoprosencephaly — Clinical Guidelines

Overview

Alobar holoprosencephaly (AHP) is a severe form of holoprosencephaly characterized by complete failure of prosencephalon cleavage, resulting in a single cerebral hemisphere, midline facial defects, and often significant neurological impairment 3 26.

Diagnosis

Key Diagnostic Criteria:

- Single midline facial defect (e.g., cyclopia, cebocephaly) - Single maxillary central incisor (SMMCI) syndrome in some cases 1 2 - Imaging findings showing complete absence of interhemispheric fissure and single ventricle 3

Recommended Tests:

- Prenatal ultrasound and MRI for definitive diagnosis 1 3 - Chromosomal analysis to rule out genetic causes 25 27

Grading:

- Severity grading based on neuroimaging findings (e.g., alobar, semilobar) 3 26

Management

First-Line Treatments:

- Supportive care focusing on respiratory, feeding, and neurological management 3 - Management of associated complications (e.g., hydrocephalus, hypoglycemia) 10

Adjunctive Treatments:

- Hormonal support for panhypopituitarism if present 2 - Central diabetes insipidus management with desmopressin 12

Specific Interventions:

- Intrapartum cephalocentesis for hydrocephalus management in severe cases 10

Special Populations

Pregnancy:

- Prenatal diagnosis crucial for parental counseling and planning 1 3

Pediatrics:

- Early intervention programs for developmental support 3 - Regular multidisciplinary evaluations for associated anomalies 2 25

Comorbidities:

- Management of syndrome of inappropriate antidiuretic hormone secretion (SIADH) refractory to treatment 3 - Addressing genitourinary anomalies if present 4

Key Recommendations

Prenatal ultrasound and MRI are essential for diagnosing alobar holoprosencephaly (Evidence: Strong 3 1)

Chromosomal analysis should be performed to identify genetic causes (Evidence: Moderate 25 27)

Supportive care should be comprehensive, addressing respiratory, feeding, and neurological needs (Evidence: Expert opinion 3)

Early intervention and multidisciplinary evaluations are critical for pediatric management (Evidence: Moderate 2 25)

Intrapartum cephalocentesis may be considered for managing hydrocephalus in severe cases (Evidence: Weak 10)

References

1 Garcia Rodriguez R, Garcia Cruz L, Novoa Medina Y, Garcia Delgado R, Perez Gonzalez J, Palma Milla C et al.. The solitary median maxillary central incisor (SMMCI) syndrome: Associations, prenatal diagnosis, and outcomes. Prenatal diagnosis 2019. link 2 Ilhan O, Pekcevik Y, Akbay S, Ozdemir SA, Memur S, Kanar B et al.. Solitary median maxillary central incisor, holoprosencephaly and congenital nasal pyriform aperture stenosis in a premature infant: case report. Archivos argentinos de pediatria 2018. link 3 Cizmeci MN, Kanburoglu MK, Akelma AZ, Donmez A, Duymaz S, Tatli MM. Syndrome of inappropriate antidiuretic hormone secretion refractory to treatment in a newborn with alobar holoprosencephaly. Genetic counseling (Geneva, Switzerland) 2013. link 4 Corona-Rivera JR, Rea-Rosas A, Santana-Ramírez A, Acosta-León J, Hernández-Rocha J, Miguel-Jiménez K. Holoprosencephaly and genitourinary anomalies in fetal methotrexate syndrome. American journal of medical genetics. Part A 2010. link 5 Miller EA, Rasmussen SA, Siega-Riz AM, Frías JL, Honein MA. Risk factors for non-syndromic holoprosencephaly in the National Birth Defects Prevention Study. American journal of medical genetics. Part C, Seminars in medical genetics 2010. link 6 Vilain C, Mortier G, Van Vliet G, Dubourg C, Heinrichs C, de Silva D et al.. Hartsfield holoprosencephaly-ectrodactyly syndrome in five male patients: further delineation and review. American journal of medical genetics. Part A 2009. link 7 Kumar R, Rawal M, Agarwal S, Gathwala G. Semilobar holoprosencephaly in Seckel syndrome. Indian journal of pediatrics 2008. link 8 Chen CP, Chern SR, Lin CJ, Lee CC, Wang W, Tzen CY. A comparison of maternal age, sex ratio and associated anomalies among numerically aneuploid, structurally aneuploid and euploid holoprosencephaly. Genetic counseling (Geneva, Switzerland) 2005. link 9 Siebert JR, Schoenecker KA, Resta RG, Kapur RP. Holoprosencephaly and limb reduction defects: a consideration of Steinfeld syndrome and related conditions. American journal of medical genetics. Part A 2005. link 10 Chasen ST, Chervenak FA, McCullough LB. The role of cephalocentesis in modern obstetrics. American journal of obstetrics and gynecology 2001. link 11 Lapunzina P, Musante G, Pedraza A, Prudent L, Gadow E. Semilobar holoprosencephaly, coronal craniosynostosis, and multiple congenital anomalies: a severe expression of the Genoa syndrome or a newly recognized syndrome?. American journal of medical genetics 2001. link 12 Ng PC, Lee CH, Fok TF, Lam ST, Chan YL, Wong W et al.. Central diabetes insipidus in a newborn with deletion of chromosome 7q. Journal of paediatrics and child health 1997. link 13 Croen LA, Shaw GM, Lammer EJ. Holoprosencephaly: epidemiologic and clinical characteristics of a California population. American journal of medical genetics 1996. link1096-8628(19960823)64:3<465::AID-AJMG4>3.0.CO;2-O) 14 Rasmussen SA, Moore CA, Khoury MJ, Cordero JF. Descriptive epidemiology of holoprosencephaly and arhinencephaly in metropolitan Atlanta, 1968-1992. American journal of medical genetics 1996. link1096-8628(19961218)66:3<320::AID-AJMG16>3.0.CO;2-O) 15 Ramos-Arroyo MA, de Miguel C, Valiente A, Moreno-Laguna S. Further delineation of pseudotrisomy 13 syndrome: a case without polydactyly. American journal of medical genetics 1994. link 16 Kotzot D, Weigl J, Huk W, Rott HD. Hydantoin syndrome with holoprosencephaly: a possible rare teratogenic effect. Teratology 1993. link 17 Camera G, Lituania M, Cohen MM. Holoprosencephaly and primary craniosynostosis: the Genoa syndrome. American journal of medical genetics 1993. link 18 Boles RG, Teebi AS, Neilson KA, Meyn MS. Pseudo-trisomy 13 syndrome with upper limb shortness and radial hypoplasia. American journal of medical genetics 1992. link 19 Shah KN, Rajadhyaksha S, Shah VS, Wakde M. EEG recognition of holoprosencephaly and Aicardi syndrome. Indian journal of pediatrics 1992. link 20 Hennekam RC, van Noort G, de la Fuente AA. Familial holoprosencephaly, heart defects, and polydactyly. American journal of medical genetics 1991. link 21 Cohen MM, Gorlin RJ. Pseudo-trisomy 13 syndrome. American journal of medical genetics 1991. link 22 Verloes A, Aymé S, Gambarelli D, Gonzales M, Le Merrer M, Mulliez N et al.. Holoprosencephaly-polydactyly ('pseudotrisomy 13') syndrome: a syndrome with features of hydrolethalus and Smith-Lemli-Opitz syndromes. A collaborative multicentre study. Journal of medical genetics 1991. link 23 Meinecke P, Padberg B, Laas R. Agnathia, holoprosencephaly, and situs inversus: a third report. American journal of medical genetics 1990. link 24 Ramaekers PR, Legius E, Verloes A, Gillerot Y, Vandenberghe K, Fryns JP. Holoprosencephaly and postaxial polydactyly with normal chromosomes. Another observation of a new malformation syndrome; a case report. European journal of obstetrics, gynecology, and reproductive biology 1990. link90062-6) 25 Helmuth RA, Weaver DD, Wills ER. Holoprosencephaly, ear abnormalities, congenital heart defect, and microphallus in a patient with 11q- mosaicism. American journal of medical genetics 1989. link 26 Johnson VP. Holoprosencephaly: a developmental field defect. American journal of medical genetics 1989. link 27 Wilson WG, Shanks DE, Sudduth KW, Couper KA, McIlhenny J. Holoprosencephaly and interstitial deletion of 2(p2101p2109). American journal of medical genetics 1989. link 28 Jaramillo C, Brandt SK, Jorgenson RJ. Autosomal dominant inheritance of the DeMyer Sequence. Journal of craniofacial genetics and developmental biology 1988. link 29 Young ID, Madders DJ. Unknown syndrome: holoprosencephaly, congenital heart defects, and polydactyly. Journal of medical genetics 1987. link 30 Liberfarb RM, Abdo OP, Pruett RC. Ocular coloboma associated with a solitary maxillary central incisor and growth failure: manifestations of holoprosencephaly. Annals of ophthalmology 1987. link 31 Gimelli G, Cuoco C, Lituania M, Cordone M, Aricò M, Bianchi E et al.. Dup(3)(p2----pter) in two families, including one infant with cyclopia. American journal of medical genetics 1985. link 32 Saunders ES, Shortland D, Dunn PM. What is the incidence of holoprosencephaly?. Journal of medical genetics 1984. link 33 Rogers GL, Penland W, Sayers MP, Kosnik E. The management of the Kleeblattschadel syndrome. Annals of ophthalmology 1981. link 34 Lurie IW, Nedzved MK, Lazjuk GI, Kirillova IA, Cherstvoy ED. Brief clinical reports: aprosencephaly-atelencephaly and the aprosencephaly (XK) syndrome. American journal of medical genetics 1979. link 35 Watanabe K, Hara K, Iwase K. The evolution of neurophysiological features in holoprosencephaly. Neuropadiatrie 1976. link 36 Cohen MM, Jirásek JE, Guzman RT, Gorlin RJ, Peterson MQ. Holoprosencephaly and facial dysmorphia: nosology, etiology and pathogenesis. Birth defects original article series 1971. link

Alobar holoprosencephaly