Q04.3 - Other reduction deformities of brain

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

• Abnormality of neurogenesis
• Abnormality of neurogenesis
• Absence of septum pellucidum
• Agenesis of cerebellum
• Agenesis of cerebellum
• Agenesis of cerebrum
• Agenesis of left hemisphere of cerebellum
• Agenesis of right hemisphere of cerebellum
• Aicardi's syndrome
• Anomalies of hypothalamus
• Anterior pituitary hormone deficiency
• Aplasia of cerebellum
• Aplasia of the vermis
• Aprosencephaly
• Arachnoid cyst
• Atelencephaly
• Autosomal recessive frontotemporal pachygyria
• Bilateral frontal polymicrogyria
• Bilateral frontoparietal polymicrogyria
• Bilateral generalized polymicrogyria
• Bilateral parasagittal parieto-occipital polymicrogyria
• Bilateral polymicrogyria
• Cerebellum agenesis with hydrocephaly
• Cerebral cortical dysgenesis
• Cobblestone lissencephaly without muscular or ocular involvement
• Combined malformation of central nervous system and skeletal muscle
• Combined malformation of central nervous system and skeletal muscle
• Complete agenesis of vermis
• Congenital absence of part of brain
• Congenital agenesis of brainstem nuclei
• Congenital bilateral perisylvian syndrome
• Congenital cerebellar hypoplasia
• Congenital cerebellar hypoplasia co-occurrent with tapetoretinal degeneration
• Congenital chorioretinal degeneration
• Congenital conduction defect
• Congenital diaphragmatic hernia
• Congenital hepatic fibrosis
• Congenital hypoplasia of cerebrum
• Congenital hypoplasia of cerebrum
• Congenital hypoplasia of inner granular layer of cerebellum
• Congenital hypoplasia of part of brain
• Congenital malformation of anterior pituitary
• Congenital muscular dystrophy with cerebellar involvement
• Congenital pontocerebellar hypoplasia
• Congenital pontocerebellar hypoplasia type 1
• Congenital pontocerebellar hypoplasia type 10
• Congenital pontocerebellar hypoplasia type 2
• Congenital pontocerebellar hypoplasia type 3
• Congenital pontocerebellar hypoplasia type 4
• Congenital pontocerebellar hypoplasia type 5
• Congenital pontocerebellar hypoplasia type 6
• Congenital pontocerebellar hypoplasia type 7
• Congenital pontocerebellar hypoplasia type 8
• Congenital pontocerebellar hypoplasia type 9
• Congenital porencephaly
• Cortical dysgenesis with pontocerebellar hypoplasia due to TUBB3 mutation
• Craniotelencephalic dysplasia
• Dyke-Davidoff-Masson syndrome
• Dysgenesis of the brainstem
• Dysgenesis of the cerebellum
• Early-onset progressive encephalopathy, hearing loss, pons hypoplasia, brain atrophy syndrome
• Endosteal hyperostoses
• Endosteal hyperostoses with cerebellar hypoplasia
• Familial aplasia of the vermis
• Familial aplasia of the vermis
• Granular cell hypoplasia
• Hemispheric cerebellar agenesis
• Hemispheric cerebral agenesis
• Hydranencephaly
• Hydranencephaly
• Hydranencephaly with proliferative vasculopathy
• Hypoplasia of brain gyri
• Infantile spasm
• Intellectual disability, coarse face, macrocephaly, cerebellar hypotrophy syndrome
• Isolated bilateral hemispheric cerebellar hypoplasia
• Isolated cerebellar vermis hypoplasia
• Isolated lissencephaly type 1 without known genetic defect
• Isolated unilateral hemispheric cerebellar hypoplasia
• Jeune thoracic dystrophy
• Joubert syndrome
• Joubert syndrome
• Joubert syndrome with congenital hepatic fibrosis
• Joubert syndrome with Jeune asphyxiating thoracic dystrophy
• Joubert syndrome with ocular defect
• Joubert syndrome with oculorenal defect
• Joubert syndrome with orofaciodigital defect
• Joubert syndrome with renal defect
• Lethal hydranencephaly, diaphragmatic hernia syndrome
• Lissencephaly
• Lissencephaly due to LIS1 mutation
• Lissencephaly due to TUBA1A mutation
• Lissencephaly syndrome Norman Roberts type
• Lissencephaly type 1 due to doublecortin gene mutation
• Lissencephaly type 3 familial fetal akinesia sequence syndrome
• Lissencephaly type 3 metacarpal bone dysplasia syndrome
• Lissencephaly with cerebellar hypoplasia
• Lissencephaly with cerebellar hypoplasia type A
• Lissencephaly with cerebellar hypoplasia type B
• Lissencephaly with cerebellar hypoplasia type C
• Lissencephaly with cerebellar hypoplasia type D
• Lissencephaly with cerebellar hypoplasia type E
• Lissencephaly with cerebellar hypoplasia type F
• Macroencephaly
• Macrogyria
• Macrogyria
• Macrogyria
• MARCH syndrome
• Megalencephaly, polymicrogyria, postaxial polydactyly, hydrocephalus syndrome
• Microcephalus, cerebellar hypoplasia, cardiac conduction defect syndrome
• Microcephaly, corpus callosum and cerebellar vermis hypoplasia, facial dysmorphism, intellectual disability syndrome
• Microcephaly, polymicrogyria, corpus callosum agenesis syndrome
• Microgyria
• Microlissencephaly
• Microlissencephaly
• Microlissencephaly micromelia syndrome
• Micromelia
• Neonatal diabetes mellitus
• Nephronophthisis
• Occipital pachygyria and polymicrogyria
• Pachygyria, intellectual disability, epilepsy syndrome
• Partial absence of septum pellucidum
• Partial agenesis of corpus callosum
• Partial corpus callosum agenesis, cerebellar vermis hypoplasia with posterior fossa cysts syndrome
• Permanent neonatal diabetes mellitus
• Permanent neonatal diabetes mellitus with cerebellar agenesis syndrome
• Polymicrogyria with optic nerve hypoplasia
• Pontine tegmental cap dysplasia
• Porencephaly, cerebellar hypoplasia, internal malformations syndrome
• Rhombencephalosynapsis
• Short rib dysplasia
• Short stature, pituitary and cerebellar defect and small sella turcica syndrome
• Type 1 lissencephaly
• Type 2 lissencephaly
• Type 3 lissencephaly
• Unilateral polymicrogyria
• White matter hypoplasia, corpus callosum agenesis, intellectual disability syndrome
• XK aprosencephaly syndrome
• X-linked intellectual disability with cerebellar hypoplasia syndrome
• X-linked lissencephaly with abnormal genitalia syndrome

Clinical Information

• Classical Lissencephalies and Subcortical Band Heterotopias-. disorders comprising a spectrum of brain malformations representing the paradigm of a diffuse neuronal migration disorder. they result in cognitive impairment; seizures; and hypotonia or spasticity. mutations of two genes, lis1, the gene for the non-catalytic subunit of platelet-activating factor acetylhydrolase ib; and dcx or xlis, the gene for doublecortin, have been identified as the most common causes of disorders in this spectrum. additional variants of classical (type i) lissencephaly have been linked to reln, the gene for reelin, and arx, the gene for aristaless related homeobox protein. (from leventer, r.j., et al, mol med today. 2000 jul;6(7):277-84 and barkovich, a.j., et al, neurology. 2005 dec 27;65(12):1873-87.)
• Cobblestone Lissencephaly-. the smooth pebbled appearance of the cerebral cortex with a thickened cortex and reduced and abnormal white matter, which results from migration of heterotopic neurons beyond the marginal zone into the leptomeninges through gaps in the external basement membrane. there is also enlarged ventricles, underdeveloped brainstem and cerebellum, and absence of the corpus callosum. these abnormalities occur as a syndrome without other birth defects (cobblestone complex) or in other syndromes associated with congenital muscular dystrophy, often involving the eye, such as the walker-warburg syndrome, fukuyama congenital muscular dystrophy, and muscle-eye-brain disease.
• Doublecortin Protein-. a microtubule-associated protein that is primarily found in neuronal precursor cells and immature neurons in embryonic and adult cortical structures.
• Lissencephaly-. a smooth brain malformation of the cerebral cortex resulting from the abnormal location of developing neurons during corticogenesis. it is characterized by an absence of normal convoluted indentations on the surface of the brain (agyria), or fewer and shallower indentations (pachygryia). there is a reduced number of cortical layers, typically 4 instead of 6, resulting in a thickened cortex, and reduced cerebral white matter that is a reversal of the normal ratio of cerebral white matter to cortex.
• Hydranencephaly-. a congenital condition where the greater portions of the cerebral hemispheres and corpus striatum are replaced by csf and glial tissue. the meninges and the skull are well formed, which is consistent with earlier normal embryogenesis of the telencephalon. bilateral occlusions of the internal carotid arteries in utero is a potential mechanism. clinical features include intact brainstem reflexes without evidence of higher cortical activity. (menkes, textbook of child neurology, 5th ed, p307)
• Neurons-. the basic cellular units of nervous tissue. each neuron consists of a body, an axon, and dendrites. their purpose is to receive, conduct, and transmit impulses in the nervous system.
• Cerebral Cortex-. the thin layer of gray matter on the surface of the cerebral hemispheres that develops from the telencephalon and folds into gyri and sulci. it reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.
• Congenital Cerebellar Hypoplasia-. hypoplasia of the cerebellum that is associated with inherited metabolic disorders and neurodegenerative disorders. signs and symptoms include mental and developmental delays, walking and balance difficulties, floppy muscle tone, and seizures.
• Congenital Diaphragmatic Hernia-. diaphragmatic hernia that is present at birth.
• Classical Lissencephaly|Lissencephaly Type I-. a genetic disorder caused by mutations in the lis1, xlis, or tuba1a genes. it results in brain malformation characterized by the underdevelopment or absence of gyri or ridges in the cerebral cortex. signs and symptoms include epilepsy and mental retardation.
• DCX Gene|DCX|DCX|Doublecortex; Lissencephaly, X-Linked (Doublecortin) Gene-. this gene is involved in neuronal migration.
• DCX wt Allele|DBCN|DC|Doublecortex; Lissencephaly, X-Linked (Doublecortin) wt Allele|LISX|SCLH|XLIS-. human dcx wild-type allele is located within xq22.3-q23 and is approximately 119 kb in length. this allele, which encodes neuronal migration protein doublecortin, plays a role in the mediation of neural migration. mutations in the gene are associated with lissencephaly x-linked type 1 and subcortical band heterotopia x-linked.
• Lissencephaly-. a rare genetic brain malformation characterized by smooth folds and grooves in the brain. there are approximately 20 different types of lissencephaly that are identified by various symptoms.
• Lissencephaly 3|LIS3-. an autosomal dominant sub-type of lissencephaly caused by mutation(s) in the tuba1a gene, encoding adhesion tubulin alpha-1a chain.
• Mental Retardation, Autosomal Recessive 34|MRT34|Mental Retardation, Autosomal Recessive 34, with Variant Lissencephaly-. an autosomal recessive condition caused by mutation(s) in the cradd gene, encoding death domain-containing protein cradd. it is characterized by mild to moderate intellectual disability and lissencephaly with anterior-predominant pachygyria.
• Miller-Dieker Syndrome|Miller-Dieker Lissencephaly Syndrome-. a rare syndrome caused by deletion of genetic material in the short arm of chromosome 17. it is characterized by an abnormally smooth brain with fewer folds and grooves. it results in intellectual disability, developmental delay, seizures, spasticity, hypotonia, and feeding difficulties. affected individuals have distinctive facial features that include a prominent forehead, midface hypoplasia, small, upturned nose, low-set ears, small jaw, and thick upper lip.
• Platelet-Activating Factor Acetylhydrolase IB Subunit Alpha|LIS-1|Lissencephaly-1 Protein|PAF Acetylhydrolase 45 kDa Subunit|PAF-AH 45 kDa Subunit|PAF-AH Alpha|PAFAH Alpha-. platelet-activating factor acetylhydrolase ib subunit alpha (410 aa, ~47 kda) is encoded by the human pafah1b1 gene. this protein is involved in neuronal migration.
• Nephrocystin-1|Juvenile Nephronophthisis 1 Protein-. nephrocystin-1 (732 aa, ~83 kda) is encoded by the human nphp1 gene. this protein is involved in the modulation of signaling.
• Nephronophthisis-. progressive tubulointerstitial injury, inherited in an autosomal recessive pattern, caused by mutations in genes involved in ciliary function, which may result in an end stage renal failure.
• Nephronophthisis 1|Familial Juvenile Nephronophthisis|Juvenile Nephronophthisis|NPH1-. progressive tubulointerstitial nephritis inherited in an autosomal recessive manner. it is caused by mutations in the nphp1 gene. patients present with anemia, polyuria, and polydipsia during childhood. the progressive bilateral kidney damage results in renal failure.
• NPHP1 Gene|NPHP1|NPHP1|Nephronophthisis 1 (Juvenile) Gene-. this gene is involved in the mediation of signal transduction.
• NPHP1 wt Allele|FLJ97602|JBTS4|NPH1|Nephronophthisis 1 (Juvenile) wt Allele|SLSN1-. human nphp1 wild-type allele is located in the vicinity of 2q13 and is approximately 83 kb in length. this allele, which encodes nephrocystin-1 protein, plays a role in the progression of adhesion-dependent signaling pathways. mutations in the gene are associated with familial juvenile nephronophthisis type 1, senior-loken syndrome type 1, and joubert syndrome type 4.
• Aprosencephaly-. a very rare congenital brain defect in which the cerebral cortex, striatum, globus pallidus, thalamus, hypothalamus, and eyes are absent or rudimentary.
• Hydranencephaly-. a rare congenital brain disorder in which the cerebral hemispheres are absent and replaced by sacs that contain cerebrospinal fluid. signs and symptoms include irritability, increased muscle tone, seizures, and hydrocephalus. the prognosis is poor.
• Bilateral Frontoparietal Polymicrogyria| BFPP-. an autosomal recessive condition caused by mutation(s) in the adgrg1 gene, encoding adhesion g-protein coupled receptor g1. it is characterized by motor and cognitive developmental delay, pyramidal signs, and seizures.
• Microgyria-. a congenital abnormality characterized by the presence of abnormally small convolutions in the brain. it results in mental retardation.
• Polymicrogyria-. a developmental brain abnormality characterized by an excessive amount of small convolutions on the surface of the brain and cognitive dysfunction.
• Permanent Neonatal Diabetes Mellitus-. hyperglycemia in the first month of life due to a genetically determined defect in the structure, secretion and/or function of insulin that does not resolve spontaneously.
• Joubert Syndrome-. a rare genetic syndrome characterized by the hypoplasia or absence of the cerebellar vermis. signs and symptoms include rapid breathing (hyperpnea), sleep apnea, abnormal eye movements, mental retardation, and ataxia.
• Joubert Syndrome 17|JBTS17-. an autosomal recessive subtype of joubert syndrome caused by mutation(s) in the cplane1 gene, encoding ciliogenesis and planar polarity effector 1.
• Joubert Syndrome 3|JBTS3-. an autosomal recessive subtype of joubert syndrome caused by mutation(s) in the ahi1 gene, encoding jouberin.
• Joubert Syndrome 4-. a rare genetic syndrome caused by mutations in the nphp1 gene. it is characterized by the hypoplasia or absence of the cerebellar vermis. signs and symptoms include rapid breathing (hyperpnea), sleep apnea, abnormal eye movements, mental retardation, and ataxia.
• Joubert Syndrome 7|JBTS7-. an autosomal recessive sub-type of joubert syndrome caused by mutation(s) in the rpgrip1l gene, encoding a protein thought to function in programmed cell death. it is characterized by cerebellar and oculomotor apraxia, hypotonia and psychomotor delay, neonatal respiratory abnormalities, renal abnormalities, and retinal dystrophy.
• Joubert Syndrome 9|JBTS9-. an autosomal recessive subtype of joubert syndrome caused by mutation(s) in the cc2d2a gene, encoding coiled-coil and c2 domain-containing protein 2a.
• Congenital Hepatic Fibrosis-. a congenital disorder usually inherited in an autosomal recessive pattern. it affects the hepatobiliary system and the kidneys. it is characterized by liver fibrosis, portal hypertension, and renal cysts.

Present on Admission (POA)

Q04.3 is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here.

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Patient Education

Brain Malformations

Most brain malformations begin long before a baby is born. Something damages the developing nervous system or causes it to develop abnormally. Sometimes it's a genetic problem. In other cases, exposure to certain medicines, infections, or radiation during pregnancy interferes with brain development. Parts of the brain may be missing, abnormally small or large, or not fully developed.

Treatment depends upon the problem. In many cases, treatment only helps with symptoms. It may include antiseizure medicines, shunts to drain fluid from the brain, and physical therapy.

There are head malformations that do not involve the brain. Craniofacial disorders are the result of abnormal growth of soft tissue and bones in the face and head. It's common for new babies to have slightly uneven heads, but parents should watch the shape of their baby's head for possible problems.

NIH: National Institute of Neurological Disorders and Stroke

Isolated lissencephaly sequence

Isolated lissencephaly sequence (ILS) is a condition that affects brain development before birth. Normally, the cells that make up the exterior of the brain (cerebral cortex) are well-organized, multi-layered, and arranged into many folds and grooves (gyri). In people with ILS, the cells of the cerebral cortex are disorganized, and the brain surface is abnormally smooth with an absence (agyria) or reduction (pachygyria) of folds and grooves. In most cases, these abnormalities impair brain growth, causing the brain to be smaller than normal (microcephaly). This underdevelopment of the brain causes severe intellectual disability, delayed development, and recurrent seizures (epilepsy) in individuals with ILS.

More than 90 percent of individuals with ILS develop epilepsy, often within the first year of life. Up to 80 percent of infants with ILS have a type of seizure called infantile spasms, these seizures can be severe enough to cause brain dysfunction (epileptic encephalopathy). After the first months of life, most children with ILS develop a variety of seizure types, including persisting infantile spasms, short periods of loss of consciousness (absence seizures); sudden episodes of weak muscle tone (drop attacks); rapid, uncontrolled muscle jerks (myoclonic seizures); and episodes of muscle rigidity, convulsions, and loss of consciousness (tonic-clonic seizures).

Infants with ILS may have poor muscle tone (hypotonia) and difficulty feeding, which leads to poor growth overall. Hypotonia also affects the muscles used for breathing, which often causes breathing problems that can lead to a life-threatening bacterial lung infection known as aspiration pneumonia. Children with ILS often develop muscle stiffness (spasticity) in their arms and legs and an abnormal side-to-side curvature of the spine (scoliosis). Rarely, the muscle stiffness will progress to paralysis (spastic paraplegia). Individuals with ILS cannot walk and rarely crawl. Most children with ILS do not develop communication skills.

Lissencephaly with cerebellar hypoplasia

Lissencephaly with cerebellar hypoplasia (LCH) affects brain development, resulting in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. In addition, the part of the brain that coordinates movement is unusually small and underdeveloped (cerebellar hypoplasia). Other parts of the brain are also often underdeveloped in LCH, including the hippocampus, which plays a role in learning and memory, and the part of the brain that is connected to the spinal cord (the brainstem).

Individuals with LCH have moderate to severe intellectual disability and delayed development. They have few or no communication skills, extremely poor muscle tone (hypotonia), problems with coordination and balance (ataxia), and difficulty sitting or standing without support. Most affected children experience recurrent seizures (epilepsy) that begin within the first months of life. Some affected individuals have nearsightedness (myopia), involuntary eye movements (nystagmus), or puffiness or swelling caused by a buildup of fluids in the body's tissues (lymphedema).

X-linked lissencephaly with abnormal genitalia

X-linked lissencephaly with abnormal genitalia (XLAG) is a condition that affects the development of the brain and genitalia. It occurs most often in males.

XLAG is characterized by abnormal brain development that results in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. Individuals without any folds in the brain (agyria) typically have more severe symptoms than people with reduced folds and grooves (pachygyria). Individuals with XLAG may also have a lack of development (agenesis) of the tissue connecting the left and right halves of the brain (corpus callosum). The brain abnormalities can cause severe intellectual disability and developmental delay, abnormal muscle stiffness (spasticity), weak muscle tone (hypotonia), and feeding difficulties. Starting soon after birth, babies with XLAG have frequent and recurrent seizures (epilepsy). Most children with XLAG do not survive past early childhood.

Another key feature of XLAG in males is abnormal genitalia that can include an unusually small penis (micropenis), undescended testes (cryptorchidism), or external genitalia that do not look clearly male or clearly female (ambiguous genitalia).

Additional signs and symptoms of XLAG include chronic diarrhea, periods of increased blood sugar (transient hyperglycemia), and problems with body temperature regulation.

Code History

• FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
• FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
• FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
• FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
• FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
• FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
• FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
• FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)